Merge tag 'mm-nonmm-stable-2023-06-24-19-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-mm updates from Andrew Morton:

 - Arnd Bergmann has fixed a bunch of -Wmissing-prototypes in top-level
   directories

 - Douglas Anderson has added a new "buddy" mode to the hardlockup
   detector. It permits the detector to work on architectures which
   cannot provide the required interrupts, by having CPUs periodically
   perform checks on other CPUs

 - Zhen Lei has enhanced kexec's ability to support two crash regions

 - Petr Mladek has done a lot of cleanup on the hard lockup detector's
   Kconfig entries

 - And the usual bunch of singleton patches in various places

* tag 'mm-nonmm-stable-2023-06-24-19-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (72 commits)
  kernel/time/posix-stubs.c: remove duplicated include
  ocfs2: remove redundant assignment to variable bit_off
  watchdog/hardlockup: fix typo in config HARDLOCKUP_DETECTOR_PREFER_BUDDY
  powerpc: move arch_trigger_cpumask_backtrace from nmi.h to irq.h
  devres: show which resource was invalid in __devm_ioremap_resource()
  watchdog/hardlockup: define HARDLOCKUP_DETECTOR_ARCH
  watchdog/sparc64: define HARDLOCKUP_DETECTOR_SPARC64
  watchdog/hardlockup: make HAVE_NMI_WATCHDOG sparc64-specific
  watchdog/hardlockup: declare arch_touch_nmi_watchdog() only in linux/nmi.h
  watchdog/hardlockup: make the config checks more straightforward
  watchdog/hardlockup: sort hardlockup detector related config values a logical way
  watchdog/hardlockup: move SMP barriers from common code to buddy code
  watchdog/buddy: simplify the dependency for HARDLOCKUP_DETECTOR_PREFER_BUDDY
  watchdog/buddy: don't copy the cpumask in watchdog_next_cpu()
  watchdog/buddy: cleanup how watchdog_buddy_check_hardlockup() is called
  watchdog/hardlockup: remove softlockup comment in touch_nmi_watchdog()
  watchdog/hardlockup: in watchdog_hardlockup_check() use cpumask_copy()
  watchdog/hardlockup: don't use raw_cpu_ptr() in watchdog_hardlockup_kick()
  watchdog/hardlockup: HAVE_NMI_WATCHDOG must implement watchdog_hardlockup_probe()
  watchdog/hardlockup: keep kernel.nmi_watchdog sysctl as 0444 if probe fails
  ...

arch/Kconfig

@@ -426,20 +426,14 @@ config HAVE_HARDLOCKUP_DETECTOR_PERF
 	  The arch chooses to use the generic perf-NMI-based hardlockup
 	  detector. Must define HAVE_PERF_EVENTS_NMI.
 
-config HAVE_NMI_WATCHDOG
-	depends on HAVE_NMI
-	bool
-	help
-	  The arch provides a low level NMI watchdog. It provides
-	  asm/nmi.h, and defines its own arch_touch_nmi_watchdog().
-
 config HAVE_HARDLOCKUP_DETECTOR_ARCH
 	bool
-	select HAVE_NMI_WATCHDOG
 	help
-	  The arch chooses to provide its own hardlockup detector, which is
+	  The arch provides its own hardlockup detector implementation instead
-	  a superset of the HAVE_NMI_WATCHDOG. It also conforms to config
+	  of the generic ones.
-	  interfaces and parameters provided by hardlockup detector subsystem.
+
+	  It uses the same command line parameters, and sysctl interface,
+	  as the generic hardlockup detectors.
 
 config HAVE_PERF_REGS
 	bool

arch/arm/include/asm/irq.h

@@ -27,7 +27,6 @@ struct irqaction;
 struct pt_regs;
 
 void handle_IRQ(unsigned int, struct pt_regs *);
-void init_IRQ(void);
 
 #ifdef CONFIG_SMP
 #include <linux/cpumask.h>

arch/arm64/Kconfig

@@ -204,6 +204,8 @@ config ARM64
 	select HAVE_FUNCTION_ERROR_INJECTION
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_GCC_PLUGINS
+	select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && \
+		HW_PERF_EVENTS && HAVE_PERF_EVENTS_NMI
 	select HAVE_HW_BREAKPOINT if PERF_EVENTS
 	select HAVE_IOREMAP_PROT
 	select HAVE_IRQ_TIME_ACCOUNTING
@@ -211,6 +213,7 @@ config ARM64
 	select HAVE_MOD_ARCH_SPECIFIC
 	select HAVE_NMI
 	select HAVE_PERF_EVENTS
+	select HAVE_PERF_EVENTS_NMI if ARM64_PSEUDO_NMI
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
 	select HAVE_PREEMPT_DYNAMIC_KEY

arch/arm64/include/asm/thread_info.h

@@ -55,10 +55,6 @@ struct thread_info {
 void arch_setup_new_exec(void);
 #define arch_setup_new_exec     arch_setup_new_exec
 
-void arch_release_task_struct(struct task_struct *tsk);
-int arch_dup_task_struct(struct task_struct *dst,
-				struct task_struct *src);
-
 #endif
 
 #define TIF_SIGPENDING		0	/* signal pending */

arch/arm64/kernel/Makefile

@@ -44,6 +44,7 @@ obj-$(CONFIG_KUSER_HELPERS)		+= kuser32.o
 obj-$(CONFIG_FUNCTION_TRACER)		+= ftrace.o entry-ftrace.o
 obj-$(CONFIG_MODULES)			+= module.o module-plts.o
 obj-$(CONFIG_PERF_EVENTS)		+= perf_regs.o perf_callchain.o
+obj-$(CONFIG_HARDLOCKUP_DETECTOR_PERF)	+= watchdog_hld.o
 obj-$(CONFIG_HAVE_HW_BREAKPOINT)	+= hw_breakpoint.o
 obj-$(CONFIG_CPU_PM)			+= sleep.o suspend.o
 obj-$(CONFIG_CPU_IDLE)			+= cpuidle.o

arch/arm64/kernel/watchdog_hld.c

@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/nmi.h>
+#include <linux/cpufreq.h>
+#include <linux/perf/arm_pmu.h>
+
+/*
+ * Safe maximum CPU frequency in case a particular platform doesn't implement
+ * cpufreq driver. Although, architecture doesn't put any restrictions on
+ * maximum frequency but 5 GHz seems to be safe maximum given the available
+ * Arm CPUs in the market which are clocked much less than 5 GHz. On the other
+ * hand, we can't make it much higher as it would lead to a large hard-lockup
+ * detection timeout on parts which are running slower (eg. 1GHz on
+ * Developerbox) and doesn't possess a cpufreq driver.
+ */
+#define SAFE_MAX_CPU_FREQ	5000000000UL // 5 GHz
+u64 hw_nmi_get_sample_period(int watchdog_thresh)
+{
+	unsigned int cpu = smp_processor_id();
+	unsigned long max_cpu_freq;
+
+	max_cpu_freq = cpufreq_get_hw_max_freq(cpu) * 1000UL;
+	if (!max_cpu_freq)
+		max_cpu_freq = SAFE_MAX_CPU_FREQ;
+
+	return (u64)max_cpu_freq * watchdog_thresh;
+}
+
+bool __init arch_perf_nmi_is_available(void)
+{
+	/*
+	 * hardlockup_detector_perf_init() will success even if Pseudo-NMI turns off,
+	 * however, the pmu interrupts will act like a normal interrupt instead of
+	 * NMI and the hardlockup detector would be broken.
+	 */
+	return arm_pmu_irq_is_nmi();
+}

arch/microblaze/include/asm/setup.h

@@ -16,8 +16,6 @@ extern char *klimit;
 
 extern void mmu_reset(void);
 
-void time_init(void);
-void init_IRQ(void);
 void machine_early_init(const char *cmdline, unsigned int ram,
 		unsigned int fdt, unsigned int msr, unsigned int tlb0,
 		unsigned int tlb1);

arch/mips/include/asm/fw/cfe/cfe_api.h

@@ -17,9 +17,6 @@
 #include <linux/types.h>
 #include <linux/string.h>
 
-typedef long intptr_t;
-
-
 /*
  * Constants
  */

arch/mips/include/asm/irq.h

@@ -19,7 +19,6 @@
 #define IRQ_STACK_SIZE			THREAD_SIZE
 #define IRQ_STACK_START			(IRQ_STACK_SIZE - 16)
 
-extern void __init init_IRQ(void);
 extern void *irq_stack[NR_CPUS];
 
 /*

arch/parisc/kernel/smp.c

@@ -271,7 +271,6 @@ void arch_send_call_function_single_ipi(int cpu)
 static void
 smp_cpu_init(int cpunum)
 {
-	extern void init_IRQ(void);    /* arch/parisc/kernel/irq.c */
 	extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
 
 	/* Set modes and Enable floating point coprocessor */

arch/powerpc/Kconfig

@@ -90,8 +90,7 @@ config NMI_IPI
 
 config PPC_WATCHDOG
 	bool
-	depends on HARDLOCKUP_DETECTOR
+	depends on HARDLOCKUP_DETECTOR_ARCH
-	depends on HAVE_HARDLOCKUP_DETECTOR_ARCH
 	default y
 	help
 	  This is a placeholder when the powerpc hardlockup detector
@@ -240,7 +239,7 @@ config PPC
 	select HAVE_GCC_PLUGINS			if GCC_VERSION >= 50200   # plugin support on gcc <= 5.1 is buggy on PPC
 	select HAVE_GENERIC_VDSO
 	select HAVE_HARDLOCKUP_DETECTOR_ARCH	if PPC_BOOK3S_64 && SMP
-	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !HAVE_HARDLOCKUP_DETECTOR_ARCH
+	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
 	select HAVE_HW_BREAKPOINT		if PERF_EVENTS && (PPC_BOOK3S || PPC_8xx)
 	select HAVE_IOREMAP_PROT
 	select HAVE_IRQ_TIME_ACCOUNTING

arch/powerpc/include/asm/irq.h

@@ -50,9 +50,14 @@ extern void *hardirq_ctx[NR_CPUS];
 extern void *softirq_ctx[NR_CPUS];
 
 void __do_IRQ(struct pt_regs *regs);
-extern void __init init_IRQ(void);
 
 int irq_choose_cpu(const struct cpumask *mask);
 
+#if defined(CONFIG_PPC_BOOK3S_64) && defined(CONFIG_NMI_IPI)
+extern void arch_trigger_cpumask_backtrace(const cpumask_t *mask,
+					   bool exclude_self);
+#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace
+#endif
+
 #endif /* _ASM_IRQ_H */
 #endif /* __KERNEL__ */

arch/powerpc/include/asm/nmi.h

@@ -3,18 +3,10 @@
 #define _ASM_NMI_H
 
 #ifdef CONFIG_PPC_WATCHDOG
-extern void arch_touch_nmi_watchdog(void);
 long soft_nmi_interrupt(struct pt_regs *regs);
-void watchdog_nmi_set_timeout_pct(u64 pct);
+void watchdog_hardlockup_set_timeout_pct(u64 pct);
 #else
-static inline void arch_touch_nmi_watchdog(void) {}
+static inline void watchdog_hardlockup_set_timeout_pct(u64 pct) {}
-static inline void watchdog_nmi_set_timeout_pct(u64 pct) {}
-#endif
-
-#ifdef CONFIG_NMI_IPI
-extern void arch_trigger_cpumask_backtrace(const cpumask_t *mask,
-					   bool exclude_self);
-#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace
 #endif
 
 extern void hv_nmi_check_nonrecoverable(struct pt_regs *regs);

arch/powerpc/kernel/watchdog.c

@@ -438,7 +438,7 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
 {
 	int cpu = smp_processor_id();
 
-	if (!(watchdog_enabled & NMI_WATCHDOG_ENABLED))
+	if (!(watchdog_enabled & WATCHDOG_HARDLOCKUP_ENABLED))
 		return HRTIMER_NORESTART;
 
 	if (!cpumask_test_cpu(cpu, &watchdog_cpumask))
@@ -479,7 +479,7 @@ static void start_watchdog(void *arg)
 		return;
 	}
 
-	if (!(watchdog_enabled & NMI_WATCHDOG_ENABLED))
+	if (!(watchdog_enabled & WATCHDOG_HARDLOCKUP_ENABLED))
 		return;
 
 	if (!cpumask_test_cpu(cpu, &watchdog_cpumask))
@@ -546,7 +546,7 @@ static void watchdog_calc_timeouts(void)
 	wd_timer_period_ms = watchdog_thresh * 1000 * 2 / 5;
 }
 
-void watchdog_nmi_stop(void)
+void watchdog_hardlockup_stop(void)
 {
 	int cpu;
 
@@ -554,7 +554,7 @@ void watchdog_nmi_stop(void)
 		stop_watchdog_on_cpu(cpu);
 }
 
-void watchdog_nmi_start(void)
+void watchdog_hardlockup_start(void)
 {
 	int cpu;
 
@@ -566,7 +566,7 @@ void watchdog_nmi_start(void)
 /*
  * Invoked from core watchdog init.
  */
-int __init watchdog_nmi_probe(void)
+int __init watchdog_hardlockup_probe(void)
 {
 	int err;
 
@@ -582,7 +582,7 @@ int __init watchdog_nmi_probe(void)
 }
 
 #ifdef CONFIG_PPC_PSERIES
-void watchdog_nmi_set_timeout_pct(u64 pct)
+void watchdog_hardlockup_set_timeout_pct(u64 pct)
 {
 	pr_info("Set the NMI watchdog timeout factor to %llu%%\n", pct);
 	WRITE_ONCE(wd_timeout_pct, pct);

arch/powerpc/platforms/pseries/mobility.c

@@ -750,7 +750,7 @@ static int pseries_migrate_partition(u64 handle)
 		goto out;
 
 	if (factor)
-		watchdog_nmi_set_timeout_pct(factor);
+		watchdog_hardlockup_set_timeout_pct(factor);
 
 	ret = pseries_suspend(handle);
 	if (ret == 0) {
@@ -766,7 +766,7 @@ static int pseries_migrate_partition(u64 handle)
 		pseries_cancel_migration(handle, ret);
 
 	if (factor)
-		watchdog_nmi_set_timeout_pct(0);
+		watchdog_hardlockup_set_timeout_pct(0);
 
 out:
 	vas_migration_handler(VAS_RESUME);

arch/riscv/include/asm/irq.h

@@ -16,6 +16,4 @@ void riscv_set_intc_hwnode_fn(struct fwnode_handle *(*fn)(void));
 
 struct fwnode_handle *riscv_get_intc_hwnode(void);
 
-extern void __init init_IRQ(void);
-
 #endif /* _ASM_RISCV_IRQ_H */

arch/riscv/include/asm/timex.h

@@ -88,6 +88,4 @@ static inline int read_current_timer(unsigned long *timer_val)
 	return 0;
 }
 
-extern void time_init(void);
-
 #endif /* _ASM_RISCV_TIMEX_H */

arch/s390/include/asm/thread_info.h

@@ -52,9 +52,6 @@ struct thread_info {
 
 struct task_struct;
 
-void arch_release_task_struct(struct task_struct *tsk);
-int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
-
 void arch_setup_new_exec(void);
 #define arch_setup_new_exec arch_setup_new_exec
 

arch/s390/kernel/entry.h

@@ -34,14 +34,12 @@ void kernel_stack_overflow(struct pt_regs * regs);
 void handle_signal32(struct ksignal *ksig, sigset_t *oldset,
 		     struct pt_regs *regs);
 
-void __init init_IRQ(void);
 void do_io_irq(struct pt_regs *regs);
 void do_ext_irq(struct pt_regs *regs);
 void do_restart(void *arg);
 void __init startup_init(void);
 void die(struct pt_regs *regs, const char *str);
 int setup_profiling_timer(unsigned int multiplier);
-void __init time_init(void);
 unsigned long prepare_ftrace_return(unsigned long parent, unsigned long sp, unsigned long ip);
 
 struct s390_mmap_arg_struct;

arch/sh/include/asm/irq.h

@@ -22,7 +22,6 @@ extern unsigned short *irq_mask_register;
 /*
  * PINT IRQs
  */
-void init_IRQ_pint(void);
 void make_imask_irq(unsigned int irq);
 
 static inline int generic_irq_demux(int irq)

arch/sh/include/asm/rtc.h

@@ -2,8 +2,6 @@
 #ifndef _ASM_RTC_H
 #define _ASM_RTC_H
 
-void time_init(void);
-
 #define RTC_CAP_4_DIGIT_YEAR	(1 << 0)
 
 struct sh_rtc_platform_info {

arch/sh/include/asm/thread_info.h

@@ -84,9 +84,6 @@ static inline struct thread_info *current_thread_info(void)
 
 #define THREAD_SIZE_ORDER	(THREAD_SHIFT - PAGE_SHIFT)
 
-extern void arch_task_cache_init(void);
-extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
-extern void arch_release_task_struct(struct task_struct *tsk);
 extern void init_thread_xstate(void);
 
 #endif /* __ASSEMBLY__ */

arch/sparc/Kconfig

@@ -33,7 +33,7 @@ config SPARC
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select GENERIC_PCI_IOMAP
 	select HAS_IOPORT
-	select HAVE_NMI_WATCHDOG if SPARC64
+	select HAVE_HARDLOCKUP_DETECTOR_SPARC64 if SPARC64
 	select HAVE_CBPF_JIT if SPARC32
 	select HAVE_EBPF_JIT if SPARC64
 	select HAVE_DEBUG_BUGVERBOSE

arch/sparc/Kconfig.debug

@@ -14,3 +14,17 @@ config FRAME_POINTER
 	bool
 	depends on MCOUNT
 	default y
+
+config HAVE_HARDLOCKUP_DETECTOR_SPARC64
+	bool
+	depends on HAVE_NMI
+	select HARDLOCKUP_DETECTOR_SPARC64
+	help
+	  Sparc64 hardlockup detector is the last one developed before adding
+	  the common infrastructure for handling hardlockup detectors. It is
+	  always built. It does _not_ use the common command line parameters
+	  and sysctl interface, except for /proc/sys/kernel/nmi_watchdog.
+
+config HARDLOCKUP_DETECTOR_SPARC64
+	bool
+	depends on HAVE_HARDLOCKUP_DETECTOR_SPARC64

arch/sparc/include/asm/irq_32.h

@@ -17,7 +17,6 @@
 
 #define irq_canonicalize(irq)	(irq)
 
-void __init init_IRQ(void);
 void __init sun4d_init_sbi_irq(void);
 
 #define NO_IRQ		0xffffffff

arch/sparc/include/asm/irq_64.h

@@ -61,7 +61,6 @@ void sun4u_destroy_msi(unsigned int irq);
 unsigned int irq_alloc(unsigned int dev_handle, unsigned int dev_ino);
 void irq_free(unsigned int irq);
 
-void __init init_IRQ(void);
 void fixup_irqs(void);
 
 static inline void set_softint(unsigned long bits)

arch/sparc/include/asm/nmi.h

@@ -8,7 +8,6 @@ void nmi_adjust_hz(unsigned int new_hz);
 
 extern atomic_t nmi_active;
 
-void arch_touch_nmi_watchdog(void);
 void start_nmi_watchdog(void *unused);
 void stop_nmi_watchdog(void *unused);
 

arch/sparc/include/asm/timer_64.h

@@ -34,7 +34,6 @@ extern struct sparc64_tick_ops *tick_ops;
 
 unsigned long sparc64_get_clock_tick(unsigned int cpu);
 void setup_sparc64_timer(void);
-void __init time_init(void);
 
 #define TICK_PRIV_BIT		BIT(63)
 #define TICKCMP_IRQ_BIT		BIT(63)

arch/sparc/kernel/kernel.h

@@ -91,7 +91,6 @@ extern int static_irq_count;
 extern spinlock_t irq_action_lock;
 
 void unexpected_irq(int irq, void *dev_id, struct pt_regs * regs);
-void init_IRQ(void);
 
 /* sun4m_irq.c */
 void sun4m_init_IRQ(void);

arch/sparc/kernel/nmi.c

@@ -65,6 +65,11 @@ void arch_touch_nmi_watchdog(void)
 }
 EXPORT_SYMBOL(arch_touch_nmi_watchdog);
 
+int __init watchdog_hardlockup_probe(void)
+{
+	return 0;
+}
+
 static void die_nmi(const char *str, struct pt_regs *regs, int do_panic)
 {
 	int this_cpu = smp_processor_id();
@@ -282,11 +287,11 @@ __setup("nmi_watchdog=", setup_nmi_watchdog);
  * sparc specific NMI watchdog enable function.
  * Enables watchdog if it is not enabled already.
  */
-int watchdog_nmi_enable(unsigned int cpu)
+void watchdog_hardlockup_enable(unsigned int cpu)
 {
 	if (atomic_read(&nmi_active) == -1) {
 		pr_warn("NMI watchdog cannot be enabled or disabled\n");
-		return -1;
+		return;
 	}
 
 	/*
@@ -295,17 +300,15 @@ int watchdog_nmi_enable(unsigned int cpu)
 	 * process first.
 	 */
 	if (!nmi_init_done)
-		return 0;
+		return;
 
 	smp_call_function_single(cpu, start_nmi_watchdog, NULL, 1);
-
-	return 0;
 }
 /*
  * sparc specific NMI watchdog disable function.
  * Disables watchdog if it is not disabled already.
  */
-void watchdog_nmi_disable(unsigned int cpu)
+void watchdog_hardlockup_disable(unsigned int cpu)
 {
 	if (atomic_read(&nmi_active) == -1)
 		pr_warn_once("NMI watchdog cannot be enabled or disabled\n");

arch/x86/include/asm/irq.h

@@ -40,8 +40,6 @@ extern void __handle_irq(struct irq_desc *desc, struct pt_regs *regs);
 
 extern void init_ISA_irqs(void);
 
-extern void __init init_IRQ(void);
-
 #ifdef CONFIG_X86_LOCAL_APIC
 void arch_trigger_cpumask_backtrace(const struct cpumask *mask,
 				    bool exclude_self);

arch/x86/include/asm/thread_info.h

@@ -232,9 +232,6 @@ static inline int arch_within_stack_frames(const void * const stack,
 			   current_thread_info()->status & TS_COMPAT)
 #endif
 
-extern void arch_task_cache_init(void);
-extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
-extern void arch_release_task_struct(struct task_struct *tsk);
 extern void arch_setup_new_exec(void);
 #define arch_setup_new_exec arch_setup_new_exec
 #endif	/* !__ASSEMBLY__ */

arch/x86/include/asm/time.h

@@ -6,7 +6,6 @@
 #include <asm/mc146818rtc.h>
 
 extern void hpet_time_init(void);
-extern void time_init(void);
 extern bool pit_timer_init(void);
 extern bool tsc_clocksource_watchdog_disabled(void);
 

arch/x86/include/asm/tsc.h

@@ -32,7 +32,6 @@ extern struct system_counterval_t convert_art_ns_to_tsc(u64 art_ns);
 
 extern void tsc_early_init(void);
 extern void tsc_init(void);
-extern unsigned long calibrate_delay_is_known(void);
 extern void mark_tsc_unstable(char *reason);
 extern int unsynchronized_tsc(void);
 extern int check_tsc_unstable(void);

drivers/perf/arm_pmu.c

@@ -689,6 +689,11 @@ static int armpmu_get_cpu_irq(struct arm_pmu *pmu, int cpu)
 	return per_cpu(hw_events->irq, cpu);
 }
 
+bool arm_pmu_irq_is_nmi(void)
+{
+	return has_nmi;
+}
+
 /*
  * PMU hardware loses all context when a CPU goes offline.
  * When a CPU is hotplugged back in, since some hardware registers are

drivers/perf/arm_pmuv3.c

@@ -22,6 +22,7 @@
 #include <linux/platform_device.h>
 #include <linux/sched_clock.h>
 #include <linux/smp.h>
+#include <linux/nmi.h>
 
 #include <asm/arm_pmuv3.h>
 
@@ -1363,10 +1364,17 @@ static struct platform_driver armv8_pmu_driver = {
 
 static int __init armv8_pmu_driver_init(void)
 {
+	int ret;
+
 	if (acpi_disabled)
-		return platform_driver_register(&armv8_pmu_driver);
+		ret = platform_driver_register(&armv8_pmu_driver);
 	else
-		return arm_pmu_acpi_probe(armv8_pmuv3_pmu_init);
+		ret = arm_pmu_acpi_probe(armv8_pmuv3_pmu_init);
+
+	if (!ret)
+		lockup_detector_retry_init();
+
+	return ret;
 }
 device_initcall(armv8_pmu_driver_init)
 

fs/ocfs2/localalloc.c

@@ -973,7 +973,7 @@ static int ocfs2_sync_local_to_main(struct ocfs2_super *osb,
 	la_start_blk = ocfs2_clusters_to_blocks(osb->sb,
 						le32_to_cpu(la->la_bm_off));
 	bitmap = la->la_bitmap;
-	start = count = bit_off = 0;
+	start = count = 0;
 	left = le32_to_cpu(alloc->id1.bitmap1.i_total);
 
 	while ((bit_off = ocfs2_find_next_zero_bit(bitmap, left, start))

fs/ocfs2/ocfs2_trace.h

@@ -1315,8 +1315,6 @@ DEFINE_OCFS2_FILE_OPS(ocfs2_sync_file);
 
 DEFINE_OCFS2_FILE_OPS(ocfs2_file_write_iter);
 
-DEFINE_OCFS2_FILE_OPS(ocfs2_file_splice_write);
-
 DEFINE_OCFS2_FILE_OPS(ocfs2_file_read_iter);
 
 DEFINE_OCFS2_FILE_OPS(ocfs2_file_splice_read);

fs/ocfs2/quota_local.c

@@ -811,7 +811,7 @@ static int ocfs2_local_free_info(struct super_block *sb, int type)
 	struct ocfs2_quota_chunk *chunk;
 	struct ocfs2_local_disk_chunk *dchunk;
 	int mark_clean = 1, len;
-	int status;
+	int status = 0;
 
 	iput(oinfo->dqi_gqinode);
 	ocfs2_simple_drop_lockres(OCFS2_SB(sb), &oinfo->dqi_gqlock);
@@ -853,17 +853,14 @@ static int ocfs2_local_free_info(struct super_block *sb, int type)
 				 oinfo->dqi_libh,
 				 olq_update_info,
 				 info);
-	if (status < 0) {
+	if (status < 0)
 		mlog_errno(status);
-		goto out;
-	}
-
 out:
 	ocfs2_inode_unlock(sb_dqopt(sb)->files[type], 1);
 	brelse(oinfo->dqi_libh);
 	brelse(oinfo->dqi_lqi_bh);
 	kfree(oinfo);
-	return 0;
+	return status;
 }
 
 static void olq_set_dquot(struct buffer_head *bh, void *private)

fs/proc/kcore.c

@@ -419,7 +419,7 @@ static ssize_t read_kcore_iter(struct kiocb *iocb, struct iov_iter *iter)
 		char *notes;
 		size_t i = 0;
 
-		strlcpy(prpsinfo.pr_psargs, saved_command_line,
+		strscpy(prpsinfo.pr_psargs, saved_command_line,
 			sizeof(prpsinfo.pr_psargs));
 
 		notes = kzalloc(notes_len, GFP_KERNEL);

fs/squashfs/block.c

@@ -17,8 +17,8 @@
 #include <linux/fs.h>
 #include <linux/vfs.h>
 #include <linux/slab.h>
+#include <linux/pagemap.h>
 #include <linux/string.h>
-#include <linux/buffer_head.h>
 #include <linux/bio.h>
 
 #include "squashfs_fs.h"
@@ -76,10 +76,101 @@ static int copy_bio_to_actor(struct bio *bio,
 	return copied_bytes;
 }
 
+static int squashfs_bio_read_cached(struct bio *fullbio,
+		struct address_space *cache_mapping, u64 index, int length,
+		u64 read_start, u64 read_end, int page_count)
+{
+	struct page *head_to_cache = NULL, *tail_to_cache = NULL;
+	struct block_device *bdev = fullbio->bi_bdev;
+	int start_idx = 0, end_idx = 0;
+	struct bvec_iter_all iter_all;
+	struct bio *bio = NULL;
+	struct bio_vec *bv;
+	int idx = 0;
+	int err = 0;
+
+	bio_for_each_segment_all(bv, fullbio, iter_all) {
+		struct page *page = bv->bv_page;
+
+		if (page->mapping == cache_mapping) {
+			idx++;
+			continue;
+		}
+
+		/*
+		 * We only use this when the device block size is the same as
+		 * the page size, so read_start and read_end cover full pages.
+		 *
+		 * Compare these to the original required index and length to
+		 * only cache pages which were requested partially, since these
+		 * are the ones which are likely to be needed when reading
+		 * adjacent blocks.
+		 */
+		if (idx == 0 && index != read_start)
+			head_to_cache = page;
+		else if (idx == page_count - 1 && index + length != read_end)
+			tail_to_cache = page;
+
+		if (!bio || idx != end_idx) {
+			struct bio *new = bio_alloc_clone(bdev, fullbio,
+							  GFP_NOIO, &fs_bio_set);
+
+			if (bio) {
+				bio_trim(bio, start_idx * PAGE_SECTORS,
+					 (end_idx - start_idx) * PAGE_SECTORS);
+				bio_chain(bio, new);
+				submit_bio(bio);
+			}
+
+			bio = new;
+			start_idx = idx;
+		}
+
+		idx++;
+		end_idx = idx;
+	}
+
+	if (bio) {
+		bio_trim(bio, start_idx * PAGE_SECTORS,
+			 (end_idx - start_idx) * PAGE_SECTORS);
+		err = submit_bio_wait(bio);
+		bio_put(bio);
+	}
+
+	if (err)
+		return err;
+
+	if (head_to_cache) {
+		int ret = add_to_page_cache_lru(head_to_cache, cache_mapping,
+						read_start >> PAGE_SHIFT,
+						GFP_NOIO);
+
+		if (!ret) {
+			SetPageUptodate(head_to_cache);
+			unlock_page(head_to_cache);
+		}
+
+	}
+
+	if (tail_to_cache) {
+		int ret = add_to_page_cache_lru(tail_to_cache, cache_mapping,
+						(read_end >> PAGE_SHIFT) - 1,
+						GFP_NOIO);
+
+		if (!ret) {
+			SetPageUptodate(tail_to_cache);
+			unlock_page(tail_to_cache);
+		}
+	}
+
+	return 0;
+}
+
 static int squashfs_bio_read(struct super_block *sb, u64 index, int length,
 			     struct bio **biop, int *block_offset)
 {
 	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	struct address_space *cache_mapping = msblk->cache_mapping;
 	const u64 read_start = round_down(index, msblk->devblksize);
 	const sector_t block = read_start >> msblk->devblksize_log2;
 	const u64 read_end = round_up(index + length, msblk->devblksize);
@@ -99,21 +190,34 @@ static int squashfs_bio_read(struct super_block *sb, u64 index, int length,
 	for (i = 0; i < page_count; ++i) {
 		unsigned int len =
 			min_t(unsigned int, PAGE_SIZE - offset, total_len);
-		struct page *page = alloc_page(GFP_NOIO);
+		struct page *page = NULL;
+
+		if (cache_mapping)
+			page = find_get_page(cache_mapping,
+					     (read_start >> PAGE_SHIFT) + i);
+		if (!page)
+			page = alloc_page(GFP_NOIO);
 
 		if (!page) {
 			error = -ENOMEM;
 			goto out_free_bio;
 		}
-		if (!bio_add_page(bio, page, len, offset)) {
+
-			error = -EIO;
+		/*
-			goto out_free_bio;
+		 * Use the __ version to avoid merging since we need each page
-		}
+		 * to be separate when we check for and avoid cached pages.
+		 */
+		__bio_add_page(bio, page, len, offset);
 		offset = 0;
 		total_len -= len;
 	}
 
-	error = submit_bio_wait(bio);
+	if (cache_mapping)
+		error = squashfs_bio_read_cached(bio, cache_mapping, index,
+						 length, read_start, read_end,
+						 page_count);
+	else
+		error = submit_bio_wait(bio);
 	if (error)
 		goto out_free_bio;
 

fs/squashfs/decompressor.c

@@ -11,7 +11,6 @@
 #include <linux/types.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
-#include <linux/buffer_head.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"

fs/squashfs/decompressor_multi_percpu.c

@@ -7,7 +7,6 @@
 #include <linux/types.h>
 #include <linux/slab.h>
 #include <linux/percpu.h>
-#include <linux/buffer_head.h>
 #include <linux/local_lock.h>
 
 #include "squashfs_fs.h"

fs/squashfs/squashfs_fs_sb.h

@@ -47,6 +47,7 @@ struct squashfs_sb_info {
 	struct squashfs_cache			*block_cache;
 	struct squashfs_cache			*fragment_cache;
 	struct squashfs_cache			*read_page;
+	struct address_space			*cache_mapping;
 	int					next_meta_index;
 	__le64					*id_table;
 	__le64					*fragment_index;

fs/squashfs/super.c

@@ -329,6 +329,19 @@ static int squashfs_fill_super(struct super_block *sb, struct fs_context *fc)
 		goto failed_mount;
 	}
 
+	if (msblk->devblksize == PAGE_SIZE) {
+		struct inode *cache = new_inode(sb);
+
+		if (cache == NULL)
+			goto failed_mount;
+
+		set_nlink(cache, 1);
+		cache->i_size = OFFSET_MAX;
+		mapping_set_gfp_mask(cache->i_mapping, GFP_NOFS);
+
+		msblk->cache_mapping = cache->i_mapping;
+	}
+
 	msblk->stream = squashfs_decompressor_setup(sb, flags);
 	if (IS_ERR(msblk->stream)) {
 		err = PTR_ERR(msblk->stream);
@@ -454,6 +467,8 @@ failed_mount:
 	squashfs_cache_delete(msblk->block_cache);
 	squashfs_cache_delete(msblk->fragment_cache);
 	squashfs_cache_delete(msblk->read_page);
+	if (msblk->cache_mapping)
+		iput(msblk->cache_mapping->host);
 	msblk->thread_ops->destroy(msblk);
 	kfree(msblk->inode_lookup_table);
 	kfree(msblk->fragment_index);
@@ -572,6 +587,8 @@ static void squashfs_put_super(struct super_block *sb)
 		squashfs_cache_delete(sbi->block_cache);
 		squashfs_cache_delete(sbi->fragment_cache);
 		squashfs_cache_delete(sbi->read_page);
+		if (sbi->cache_mapping)
+			iput(sbi->cache_mapping->host);
 		sbi->thread_ops->destroy(sbi);
 		kfree(sbi->id_table);
 		kfree(sbi->fragment_index);

include/asm-generic/bug.h

@@ -87,10 +87,12 @@ struct bug_entry {
  *
  * Use the versions with printk format strings to provide better diagnostics.
  */
-#ifndef __WARN_FLAGS
 extern __printf(4, 5)
 void warn_slowpath_fmt(const char *file, const int line, unsigned taint,
 		       const char *fmt, ...);
+extern __printf(1, 2) void __warn_printk(const char *fmt, ...);
+
+#ifndef __WARN_FLAGS
 #define __WARN()		__WARN_printf(TAINT_WARN, NULL)
 #define __WARN_printf(taint, arg...) do {				\
 		instrumentation_begin();				\
@@ -98,7 +100,6 @@ void warn_slowpath_fmt(const char *file, const int line, unsigned taint,
 		instrumentation_end();					\
 	} while (0)
 #else
-extern __printf(1, 2) void __warn_printk(const char *fmt, ...);
 #define __WARN()		__WARN_FLAGS(BUGFLAG_TAINT(TAINT_WARN))
 #define __WARN_printf(taint, arg...) do {				\
 		instrumentation_begin();				\

include/linux/acpi.h

@@ -712,7 +712,6 @@ int acpi_match_platform_list(const struct acpi_platform_list *plat);
 
 extern void acpi_early_init(void);
 extern void acpi_subsystem_init(void);
-extern void arch_post_acpi_subsys_init(void);
 
 extern int acpi_nvs_register(__u64 start, __u64 size);
 
@@ -1084,6 +1083,8 @@ static inline bool acpi_sleep_state_supported(u8 sleep_state)
 
 #endif	/* !CONFIG_ACPI */
 
+extern void arch_post_acpi_subsys_init(void);
+
 #ifdef CONFIG_ACPI_HOTPLUG_IOAPIC
 int acpi_ioapic_add(acpi_handle root);
 #else

include/linux/delay.h

@@ -56,6 +56,7 @@ static inline void ndelay(unsigned long x)
 
 extern unsigned long lpj_fine;
 void calibrate_delay(void);
+unsigned long calibrate_delay_is_known(void);
 void __attribute__((weak)) calibration_delay_done(void);
 void msleep(unsigned int msecs);
 unsigned long msleep_interruptible(unsigned int msecs);

include/linux/init.h

@@ -152,6 +152,24 @@ extern unsigned int reset_devices;
 void setup_arch(char **);
 void prepare_namespace(void);
 void __init init_rootfs(void);
+
+void init_IRQ(void);
+void time_init(void);
+void mem_encrypt_init(void);
+void poking_init(void);
+void pgtable_cache_init(void);
+
+extern initcall_entry_t __initcall_start[];
+extern initcall_entry_t __initcall0_start[];
+extern initcall_entry_t __initcall1_start[];
+extern initcall_entry_t __initcall2_start[];
+extern initcall_entry_t __initcall3_start[];
+extern initcall_entry_t __initcall4_start[];
+extern initcall_entry_t __initcall5_start[];
+extern initcall_entry_t __initcall6_start[];
+extern initcall_entry_t __initcall7_start[];
+extern initcall_entry_t __initcall_end[];
+
 extern struct file_system_type rootfs_fs_type;
 
 #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
@@ -309,6 +327,8 @@ struct obs_kernel_param {
 	int early;
 };
 
+extern const struct obs_kernel_param __setup_start[], __setup_end[];
+
 /*
  * Only for really core code.  See moduleparam.h for the normal way.
  *

include/linux/kcov.h

@@ -72,6 +72,23 @@ static inline void kcov_remote_stop_softirq(void)
 		kcov_remote_stop();
 }
 
+#ifdef CONFIG_64BIT
+typedef unsigned long kcov_u64;
+#else
+typedef unsigned long long kcov_u64;
+#endif
+
+void __sanitizer_cov_trace_pc(void);
+void __sanitizer_cov_trace_cmp1(u8 arg1, u8 arg2);
+void __sanitizer_cov_trace_cmp2(u16 arg1, u16 arg2);
+void __sanitizer_cov_trace_cmp4(u32 arg1, u32 arg2);
+void __sanitizer_cov_trace_cmp8(kcov_u64 arg1, kcov_u64 arg2);
+void __sanitizer_cov_trace_const_cmp1(u8 arg1, u8 arg2);
+void __sanitizer_cov_trace_const_cmp2(u16 arg1, u16 arg2);
+void __sanitizer_cov_trace_const_cmp4(u32 arg1, u32 arg2);
+void __sanitizer_cov_trace_const_cmp8(kcov_u64 arg1, kcov_u64 arg2);
+void __sanitizer_cov_trace_switch(kcov_u64 val, void *cases);
+
 #else
 
 static inline void kcov_task_init(struct task_struct *t) {}

include/linux/math.h

@@ -118,17 +118,17 @@ __STRUCT_FRACT(s32)
 __STRUCT_FRACT(u32)
 #undef __STRUCT_FRACT
 
-/*
+/* Calculate "x * n / d" without unnecessary overflow or loss of precision. */
- * Multiplies an integer by a fraction, while avoiding unnecessary
+#define mult_frac(x, n, d)	\
- * overflow or loss of precision.
+({				\
- */
+	typeof(x) x_ = (x);	\
-#define mult_frac(x, numer, denom)(			\
+	typeof(n) n_ = (n);	\
-{							\
+	typeof(d) d_ = (d);	\
-	typeof(x) quot = (x) / (denom);			\
+				\
-	typeof(x) rem  = (x) % (denom);			\
+	typeof(x_) q = x_ / d_;	\
-	(quot * (numer)) + ((rem * (numer)) / (denom));	\
+	typeof(x_) r = x_ % d_;	\
-}							\
+	q * n_ + r * n_ / d_;	\
-)
+})
 
 #define sector_div(a, b) do_div(a, b)
 

include/linux/mm.h

@@ -3491,13 +3491,12 @@ static inline bool debug_pagealloc_enabled_static(void)
 	return static_branch_unlikely(&_debug_pagealloc_enabled);
 }
 
-#ifdef CONFIG_DEBUG_PAGEALLOC
 /*
  * To support DEBUG_PAGEALLOC architecture must ensure that
  * __kernel_map_pages() never fails
  */
 extern void __kernel_map_pages(struct page *page, int numpages, int enable);
-
+#ifdef CONFIG_DEBUG_PAGEALLOC
 static inline void debug_pagealloc_map_pages(struct page *page, int numpages)
 {
 	if (debug_pagealloc_enabled_static())

include/linux/mount.h

@@ -123,4 +123,6 @@ extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,
 			  struct vfsmount *);
 extern void kern_unmount_array(struct vfsmount *mnt[], unsigned int num);
 
+extern int cifs_root_data(char **dev, char **opts);
+
 #endif /* _LINUX_MOUNT_H */

include/linux/nmi.h

@@ -7,19 +7,19 @@
 
 #include <linux/sched.h>
 #include <asm/irq.h>
-#if defined(CONFIG_HAVE_NMI_WATCHDOG)
+
+/* Arch specific watchdogs might need to share extra watchdog-related APIs. */
+#if defined(CONFIG_HARDLOCKUP_DETECTOR_ARCH) || defined(CONFIG_HARDLOCKUP_DETECTOR_SPARC64)
 #include <asm/nmi.h>
 #endif
 
 #ifdef CONFIG_LOCKUP_DETECTOR
 void lockup_detector_init(void);
+void lockup_detector_retry_init(void);
 void lockup_detector_soft_poweroff(void);
 void lockup_detector_cleanup(void);
-bool is_hardlockup(void);
 
 extern int watchdog_user_enabled;
-extern int nmi_watchdog_user_enabled;
-extern int soft_watchdog_user_enabled;
 extern int watchdog_thresh;
 extern unsigned long watchdog_enabled;
 
@@ -35,6 +35,7 @@ extern int sysctl_hardlockup_all_cpu_backtrace;
 
 #else /* CONFIG_LOCKUP_DETECTOR */
 static inline void lockup_detector_init(void) { }
+static inline void lockup_detector_retry_init(void) { }
 static inline void lockup_detector_soft_poweroff(void) { }
 static inline void lockup_detector_cleanup(void) { }
 #endif /* !CONFIG_LOCKUP_DETECTOR */
@@ -69,17 +70,17 @@ static inline void reset_hung_task_detector(void) { }
  * 'watchdog_enabled' variable. Each lockup detector has its dedicated bit -
  * bit 0 for the hard lockup detector and bit 1 for the soft lockup detector.
  *
- * 'watchdog_user_enabled', 'nmi_watchdog_user_enabled' and
+ * 'watchdog_user_enabled', 'watchdog_hardlockup_user_enabled' and
- * 'soft_watchdog_user_enabled' are variables that are only used as an
+ * 'watchdog_softlockup_user_enabled' are variables that are only used as an
  * 'interface' between the parameters in /proc/sys/kernel and the internal
  * state bits in 'watchdog_enabled'. The 'watchdog_thresh' variable is
  * handled differently because its value is not boolean, and the lockup
  * detectors are 'suspended' while 'watchdog_thresh' is equal zero.
  */
-#define NMI_WATCHDOG_ENABLED_BIT   0
+#define WATCHDOG_HARDLOCKUP_ENABLED_BIT  0
-#define SOFT_WATCHDOG_ENABLED_BIT  1
+#define WATCHDOG_SOFTOCKUP_ENABLED_BIT   1
-#define NMI_WATCHDOG_ENABLED      (1 << NMI_WATCHDOG_ENABLED_BIT)
+#define WATCHDOG_HARDLOCKUP_ENABLED     (1 << WATCHDOG_HARDLOCKUP_ENABLED_BIT)
-#define SOFT_WATCHDOG_ENABLED     (1 << SOFT_WATCHDOG_ENABLED_BIT)
+#define WATCHDOG_SOFTOCKUP_ENABLED      (1 << WATCHDOG_SOFTOCKUP_ENABLED_BIT)
 
 #if defined(CONFIG_HARDLOCKUP_DETECTOR)
 extern void hardlockup_detector_disable(void);
@@ -88,52 +89,63 @@ extern unsigned int hardlockup_panic;
 static inline void hardlockup_detector_disable(void) {}
 #endif
 
-#if defined(CONFIG_HAVE_NMI_WATCHDOG) || defined(CONFIG_HARDLOCKUP_DETECTOR)
+/* Sparc64 has special implemetantion that is always enabled. */
-# define NMI_WATCHDOG_SYSCTL_PERM	0644
+#if defined(CONFIG_HARDLOCKUP_DETECTOR) || defined(CONFIG_HARDLOCKUP_DETECTOR_SPARC64)
+void arch_touch_nmi_watchdog(void);
 #else
-# define NMI_WATCHDOG_SYSCTL_PERM	0444
+static inline void arch_touch_nmi_watchdog(void) { }
+#endif
+
+#if defined(CONFIG_HARDLOCKUP_DETECTOR_COUNTS_HRTIMER)
+void watchdog_hardlockup_touch_cpu(unsigned int cpu);
+void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs);
 #endif
 
 #if defined(CONFIG_HARDLOCKUP_DETECTOR_PERF)
-extern void arch_touch_nmi_watchdog(void);
 extern void hardlockup_detector_perf_stop(void);
 extern void hardlockup_detector_perf_restart(void);
-extern void hardlockup_detector_perf_disable(void);
-extern void hardlockup_detector_perf_enable(void);
 extern void hardlockup_detector_perf_cleanup(void);
-extern int hardlockup_detector_perf_init(void);
 #else
 static inline void hardlockup_detector_perf_stop(void) { }
 static inline void hardlockup_detector_perf_restart(void) { }
-static inline void hardlockup_detector_perf_disable(void) { }
-static inline void hardlockup_detector_perf_enable(void) { }
 static inline void hardlockup_detector_perf_cleanup(void) { }
-# if !defined(CONFIG_HAVE_NMI_WATCHDOG)
-static inline int hardlockup_detector_perf_init(void) { return -ENODEV; }
-static inline void arch_touch_nmi_watchdog(void) {}
-# else
-static inline int hardlockup_detector_perf_init(void) { return 0; }
-# endif
 #endif
 
-void watchdog_nmi_stop(void);
+void watchdog_hardlockup_stop(void);
-void watchdog_nmi_start(void);
+void watchdog_hardlockup_start(void);
-int watchdog_nmi_probe(void);
+int watchdog_hardlockup_probe(void);
-int watchdog_nmi_enable(unsigned int cpu);
+void watchdog_hardlockup_enable(unsigned int cpu);
-void watchdog_nmi_disable(unsigned int cpu);
+void watchdog_hardlockup_disable(unsigned int cpu);
 
 void lockup_detector_reconfigure(void);
 
+#ifdef CONFIG_HARDLOCKUP_DETECTOR_BUDDY
+void watchdog_buddy_check_hardlockup(int hrtimer_interrupts);
+#else
+static inline void watchdog_buddy_check_hardlockup(int hrtimer_interrupts) {}
+#endif
+
 /**
- * touch_nmi_watchdog - restart NMI watchdog timeout.
+ * touch_nmi_watchdog - manually reset the hardlockup watchdog timeout.
  *
- * If the architecture supports the NMI watchdog, touch_nmi_watchdog()
+ * If we support detecting hardlockups, touch_nmi_watchdog() may be
- * may be used to reset the timeout - for code which intentionally
+ * used to pet the watchdog (reset the timeout) - for code which
- * disables interrupts for a long time. This call is stateless.
+ * intentionally disables interrupts for a long time. This call is stateless.
+ *
+ * Though this function has "nmi" in the name, the hardlockup watchdog might
+ * not be backed by NMIs. This function will likely be renamed to
+ * touch_hardlockup_watchdog() in the future.
  */
 static inline void touch_nmi_watchdog(void)
 {
+	/*
+	 * Pass on to the hardlockup detector selected via CONFIG_. Note that
+	 * the hardlockup detector may not be arch-specific nor using NMIs
+	 * and the arch_touch_nmi_watchdog() function will likely be renamed
+	 * in the future.
+	 */
 	arch_touch_nmi_watchdog();
+
 	touch_softlockup_watchdog();
 }
 
@@ -194,10 +206,11 @@ static inline bool trigger_single_cpu_backtrace(int cpu)
 
 #ifdef CONFIG_HARDLOCKUP_DETECTOR_PERF
 u64 hw_nmi_get_sample_period(int watchdog_thresh);
+bool arch_perf_nmi_is_available(void);
 #endif
 
 #if defined(CONFIG_HARDLOCKUP_CHECK_TIMESTAMP) && \
-    defined(CONFIG_HARDLOCKUP_DETECTOR)
+    defined(CONFIG_HARDLOCKUP_DETECTOR_PERF)
 void watchdog_update_hrtimer_threshold(u64 period);
 #else
 static inline void watchdog_update_hrtimer_threshold(u64 period) { }

include/linux/panic.h

@@ -32,6 +32,9 @@ extern int sysctl_panic_on_stackoverflow;
 
 extern bool crash_kexec_post_notifiers;
 
+extern void __stack_chk_fail(void);
+void abort(void);
+
 /*
  * panic_cpu is used for synchronizing panic() and crash_kexec() execution. It
  * holds a CPU number which is executing panic() currently. A value of

include/linux/percpu.h

@@ -103,12 +103,10 @@ extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);
 extern void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
 					 void *base_addr);
 
-#ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
 extern int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
 				size_t atom_size,
 				pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
 				pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);
-#endif
 
 #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
 void __init pcpu_populate_pte(unsigned long addr);

include/linux/perf/arm_pmu.h

@@ -173,6 +173,8 @@ void kvm_host_pmu_init(struct arm_pmu *pmu);
 #define kvm_host_pmu_init(x)	do { } while(0)
 #endif
 
+bool arm_pmu_irq_is_nmi(void);
+
 /* Internal functions only for core arm_pmu code */
 struct arm_pmu *armpmu_alloc(void);
 void armpmu_free(struct arm_pmu *pmu);

include/linux/thread_info.h

@@ -256,6 +256,11 @@ check_copy_size(const void *addr, size_t bytes, bool is_source)
 static inline void arch_setup_new_exec(void) { }
 #endif
 
+void arch_task_cache_init(void); /* for CONFIG_SH */
+void arch_release_task_struct(struct task_struct *tsk);
+int arch_dup_task_struct(struct task_struct *dst,
+				struct task_struct *src);
+
 #endif	/* __KERNEL__ */
 
 #endif /* _LINUX_THREAD_INFO_H */

include/linux/types.h

@@ -40,6 +40,7 @@ typedef __kernel_uid16_t        uid16_t;
 typedef __kernel_gid16_t        gid16_t;
 
 typedef unsigned long		uintptr_t;
+typedef long			intptr_t;
 
 #ifdef CONFIG_HAVE_UID16
 /* This is defined by include/asm-{arch}/posix_types.h */

init/do_mounts.c

@@ -192,8 +192,19 @@ retry:
 		printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
 				pretty_name, b, err);
 		printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
-
 		printk_all_partitions();
+
+		if (root_fs_names)
+			num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);
+		if (!num_fs)
+			pr_err("Can't find any bdev filesystem to be used for mount!\n");
+		else {
+			pr_err("List of all bdev filesystems:\n");
+			for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)
+				pr_err(" %s", p);
+			pr_err("\n");
+		}
+
 		panic("VFS: Unable to mount root fs on %s", b);
 	}
 	if (!(flags & SB_RDONLY)) {
@@ -256,8 +267,6 @@ static inline void mount_nfs_root(void)
 
 #ifdef CONFIG_CIFS_ROOT
 
-extern int cifs_root_data(char **dev, char **opts);
-
 #define CIFSROOT_TIMEOUT_MIN	5
 #define CIFSROOT_TIMEOUT_MAX	30
 #define CIFSROOT_RETRY_MAX	5

init/main.c

@@ -113,10 +113,6 @@
 
 static int kernel_init(void *);
 
-extern void init_IRQ(void);
-extern void radix_tree_init(void);
-extern void maple_tree_init(void);
-
 /*
  * Debug helper: via this flag we know that we are in 'early bootup code'
  * where only the boot processor is running with IRQ disabled.  This means
@@ -135,7 +131,6 @@ EXPORT_SYMBOL(system_state);
 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 
-extern void time_init(void);
 /* Default late time init is NULL. archs can override this later. */
 void (*__initdata late_time_init)(void);
 
@@ -194,8 +189,6 @@ static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 static const char *panic_later, *panic_param;
 
-extern const struct obs_kernel_param __setup_start[], __setup_end[];
-
 static bool __init obsolete_checksetup(char *line)
 {
 	const struct obs_kernel_param *p;
@@ -1256,17 +1249,6 @@ int __init_or_module do_one_initcall(initcall_t fn)
 }
 
 
-extern initcall_entry_t __initcall_start[];
-extern initcall_entry_t __initcall0_start[];
-extern initcall_entry_t __initcall1_start[];
-extern initcall_entry_t __initcall2_start[];
-extern initcall_entry_t __initcall3_start[];
-extern initcall_entry_t __initcall4_start[];
-extern initcall_entry_t __initcall5_start[];
-extern initcall_entry_t __initcall6_start[];
-extern initcall_entry_t __initcall7_start[];
-extern initcall_entry_t __initcall_end[];
-
 static initcall_entry_t *initcall_levels[] __initdata = {
 	__initcall0_start,
 	__initcall1_start,

kernel/Makefile

@@ -91,7 +91,8 @@ obj-$(CONFIG_FAIL_FUNCTION) += fail_function.o
 obj-$(CONFIG_KGDB) += debug/
 obj-$(CONFIG_DETECT_HUNG_TASK) += hung_task.o
 obj-$(CONFIG_LOCKUP_DETECTOR) += watchdog.o
-obj-$(CONFIG_HARDLOCKUP_DETECTOR_PERF) += watchdog_hld.o
+obj-$(CONFIG_HARDLOCKUP_DETECTOR_BUDDY) += watchdog_buddy.o
+obj-$(CONFIG_HARDLOCKUP_DETECTOR_PERF) += watchdog_perf.o
 obj-$(CONFIG_SECCOMP) += seccomp.o
 obj-$(CONFIG_RELAY) += relay.o
 obj-$(CONFIG_SYSCTL) += utsname_sysctl.o

kernel/fork.c

@@ -252,23 +252,19 @@ static int memcg_charge_kernel_stack(struct vm_struct *vm)
 {
 	int i;
 	int ret;
+	int nr_charged = 0;
 
-	BUILD_BUG_ON(IS_ENABLED(CONFIG_VMAP_STACK) && PAGE_SIZE % 1024 != 0);
 	BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE);
 
 	for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) {
 		ret = memcg_kmem_charge_page(vm->pages[i], GFP_KERNEL, 0);
 		if (ret)
 			goto err;
+		nr_charged++;
 	}
 	return 0;
 err:
-	/*
+	for (i = 0; i < nr_charged; i++)
-	 * If memcg_kmem_charge_page() fails, page's memory cgroup pointer is
-	 * NULL, and memcg_kmem_uncharge_page() in free_thread_stack() will
-	 * ignore this page.
-	 */
-	for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++)
 		memcg_kmem_uncharge_page(vm->pages[i], 0);
 	return ret;
 }

kernel/kcov.c

@@ -279,7 +279,7 @@ void notrace __sanitizer_cov_trace_cmp4(u32 arg1, u32 arg2)
 }
 EXPORT_SYMBOL(__sanitizer_cov_trace_cmp4);
 
-void notrace __sanitizer_cov_trace_cmp8(u64 arg1, u64 arg2)
+void notrace __sanitizer_cov_trace_cmp8(kcov_u64 arg1, kcov_u64 arg2)
 {
 	write_comp_data(KCOV_CMP_SIZE(3), arg1, arg2, _RET_IP_);
 }
@@ -306,16 +306,17 @@ void notrace __sanitizer_cov_trace_const_cmp4(u32 arg1, u32 arg2)
 }
 EXPORT_SYMBOL(__sanitizer_cov_trace_const_cmp4);
 
-void notrace __sanitizer_cov_trace_const_cmp8(u64 arg1, u64 arg2)
+void notrace __sanitizer_cov_trace_const_cmp8(kcov_u64 arg1, kcov_u64 arg2)
 {
 	write_comp_data(KCOV_CMP_SIZE(3) | KCOV_CMP_CONST, arg1, arg2,
 			_RET_IP_);
 }
 EXPORT_SYMBOL(__sanitizer_cov_trace_const_cmp8);
 
-void notrace __sanitizer_cov_trace_switch(u64 val, u64 *cases)
+void notrace __sanitizer_cov_trace_switch(kcov_u64 val, void *arg)
 {
 	u64 i;
+	u64 *cases = arg;
 	u64 count = cases[0];
 	u64 size = cases[1];
 	u64 type = KCOV_CMP_CONST;

kernel/kexec_core.c

@@ -1091,6 +1091,11 @@ __bpf_kfunc void crash_kexec(struct pt_regs *regs)
 	}
 }
 
+static inline resource_size_t crash_resource_size(const struct resource *res)
+{
+	return !res->end ? 0 : resource_size(res);
+}
+
 ssize_t crash_get_memory_size(void)
 {
 	ssize_t size = 0;
@@ -1098,19 +1103,45 @@ ssize_t crash_get_memory_size(void)
 	if (!kexec_trylock())
 		return -EBUSY;
 
-	if (crashk_res.end != crashk_res.start)
+	size += crash_resource_size(&crashk_res);
-		size = resource_size(&crashk_res);
+	size += crash_resource_size(&crashk_low_res);
 
 	kexec_unlock();
 	return size;
 }
 
+static int __crash_shrink_memory(struct resource *old_res,
+				 unsigned long new_size)
+{
+	struct resource *ram_res;
+
+	ram_res = kzalloc(sizeof(*ram_res), GFP_KERNEL);
+	if (!ram_res)
+		return -ENOMEM;
+
+	ram_res->start = old_res->start + new_size;
+	ram_res->end   = old_res->end;
+	ram_res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM;
+	ram_res->name  = "System RAM";
+
+	if (!new_size) {
+		release_resource(old_res);
+		old_res->start = 0;
+		old_res->end   = 0;
+	} else {
+		crashk_res.end = ram_res->start - 1;
+	}
+
+	crash_free_reserved_phys_range(ram_res->start, ram_res->end);
+	insert_resource(&iomem_resource, ram_res);
+
+	return 0;
+}
+
 int crash_shrink_memory(unsigned long new_size)
 {
 	int ret = 0;
-	unsigned long start, end;
+	unsigned long old_size, low_size;
-	unsigned long old_size;
-	struct resource *ram_res;
 
 	if (!kexec_trylock())
 		return -EBUSY;
@@ -1119,36 +1150,42 @@ int crash_shrink_memory(unsigned long new_size)
 		ret = -ENOENT;
 		goto unlock;
 	}
-	start = crashk_res.start;
+
-	end = crashk_res.end;
+	low_size = crash_resource_size(&crashk_low_res);
-	old_size = (end == 0) ? 0 : end - start + 1;
+	old_size = crash_resource_size(&crashk_res) + low_size;
+	new_size = roundup(new_size, KEXEC_CRASH_MEM_ALIGN);
 	if (new_size >= old_size) {
 		ret = (new_size == old_size) ? 0 : -EINVAL;
 		goto unlock;
 	}
 
-	ram_res = kzalloc(sizeof(*ram_res), GFP_KERNEL);
+	/*
-	if (!ram_res) {
+	 * (low_size > new_size) implies that low_size is greater than zero.
-		ret = -ENOMEM;
+	 * This also means that if low_size is zero, the else branch is taken.
-		goto unlock;
+	 *
+	 * If low_size is greater than 0, (low_size > new_size) indicates that
+	 * crashk_low_res also needs to be shrunken. Otherwise, only crashk_res
+	 * needs to be shrunken.
+	 */
+	if (low_size > new_size) {
+		ret = __crash_shrink_memory(&crashk_res, 0);
+		if (ret)
+			goto unlock;
+
+		ret = __crash_shrink_memory(&crashk_low_res, new_size);
+	} else {
+		ret = __crash_shrink_memory(&crashk_res, new_size - low_size);
 	}
 
-	start = roundup(start, KEXEC_CRASH_MEM_ALIGN);
+	/* Swap crashk_res and crashk_low_res if needed */
-	end = roundup(start + new_size, KEXEC_CRASH_MEM_ALIGN);
+	if (!crashk_res.end && crashk_low_res.end) {
-
+		crashk_res.start = crashk_low_res.start;
-	crash_free_reserved_phys_range(end, crashk_res.end);
+		crashk_res.end   = crashk_low_res.end;
-
+		release_resource(&crashk_low_res);
-	if ((start == end) && (crashk_res.parent != NULL))
+		crashk_low_res.start = 0;
-		release_resource(&crashk_res);
+		crashk_low_res.end   = 0;
-
+		insert_resource(&iomem_resource, &crashk_res);
-	ram_res->start = end;
+	}
-	ram_res->end = crashk_res.end;
-	ram_res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM;
-	ram_res->name = "System RAM";
-
-	crashk_res.end = end - 1;
-
-	insert_resource(&iomem_resource, ram_res);
 
 unlock:
 	kexec_unlock();

kernel/kexec_file.c

@@ -867,6 +867,7 @@ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
 {
 	unsigned long bss_addr;
 	unsigned long offset;
+	size_t sechdrs_size;
 	Elf_Shdr *sechdrs;
 	int i;
 
@@ -874,11 +875,11 @@ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
 	 * The section headers in kexec_purgatory are read-only. In order to
 	 * have them modifiable make a temporary copy.
 	 */
-	sechdrs = vzalloc(array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum));
+	sechdrs_size = array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum);
+	sechdrs = vzalloc(sechdrs_size);
 	if (!sechdrs)
 		return -ENOMEM;
-	memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff,
+	memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff, sechdrs_size);
-	       pi->ehdr->e_shnum * sizeof(Elf_Shdr));
 	pi->sechdrs = sechdrs;
 
 	offset = 0;

kernel/kthread.c

@@ -322,10 +322,10 @@ void __noreturn kthread_exit(long result)
  * @comp: Completion to complete
  * @code: The integer value to return to kthread_stop().
  *
- * If present complete @comp and the reuturn code to kthread_stop().
+ * If present, complete @comp and then return code to kthread_stop().
  *
  * A kernel thread whose module may be removed after the completion of
- * @comp can use this function exit safely.
+ * @comp can use this function to exit safely.
  *
  * Does not return.
  */

kernel/locking/lock_events.h

@@ -57,4 +57,8 @@ static inline void __lockevent_add(enum lock_events event, int inc)
 #define lockevent_cond_inc(ev, c)
 
 #endif /* CONFIG_LOCK_EVENT_COUNTS */
+
+ssize_t lockevent_read(struct file *file, char __user *user_buf,
+		       size_t count, loff_t *ppos);
+
 #endif /* __LOCKING_LOCK_EVENTS_H */

kernel/panic.c

@@ -684,6 +684,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint,
 	add_taint(taint, LOCKDEP_STILL_OK);
 }
 
+#ifdef CONFIG_BUG
 #ifndef __WARN_FLAGS
 void warn_slowpath_fmt(const char *file, int line, unsigned taint,
 		       const char *fmt, ...)
@@ -722,8 +723,6 @@ void __warn_printk(const char *fmt, ...)
 EXPORT_SYMBOL(__warn_printk);
 #endif
 
-#ifdef CONFIG_BUG
-
 /* Support resetting WARN*_ONCE state */
 
 static int clear_warn_once_set(void *data, u64 val)

kernel/watchdog.c

@@ -29,20 +29,18 @@
 
 static DEFINE_MUTEX(watchdog_mutex);
 
-#if defined(CONFIG_HARDLOCKUP_DETECTOR) || defined(CONFIG_HAVE_NMI_WATCHDOG)
+#if defined(CONFIG_HARDLOCKUP_DETECTOR) || defined(CONFIG_HARDLOCKUP_DETECTOR_SPARC64)
-# define WATCHDOG_DEFAULT	(SOFT_WATCHDOG_ENABLED | NMI_WATCHDOG_ENABLED)
+# define WATCHDOG_HARDLOCKUP_DEFAULT	1
-# define NMI_WATCHDOG_DEFAULT	1
 #else
-# define WATCHDOG_DEFAULT	(SOFT_WATCHDOG_ENABLED)
+# define WATCHDOG_HARDLOCKUP_DEFAULT	0
-# define NMI_WATCHDOG_DEFAULT	0
 #endif
 
 unsigned long __read_mostly watchdog_enabled;
 int __read_mostly watchdog_user_enabled = 1;
-int __read_mostly nmi_watchdog_user_enabled = NMI_WATCHDOG_DEFAULT;
+static int __read_mostly watchdog_hardlockup_user_enabled = WATCHDOG_HARDLOCKUP_DEFAULT;
-int __read_mostly soft_watchdog_user_enabled = 1;
+static int __read_mostly watchdog_softlockup_user_enabled = 1;
 int __read_mostly watchdog_thresh = 10;
-static int __read_mostly nmi_watchdog_available;
+static int __read_mostly watchdog_hardlockup_available;
 
 struct cpumask watchdog_cpumask __read_mostly;
 unsigned long *watchdog_cpumask_bits = cpumask_bits(&watchdog_cpumask);
@@ -68,7 +66,7 @@ unsigned int __read_mostly hardlockup_panic =
  */
 void __init hardlockup_detector_disable(void)
 {
-	nmi_watchdog_user_enabled = 0;
+	watchdog_hardlockup_user_enabled = 0;
 }
 
 static int __init hardlockup_panic_setup(char *str)
@@ -78,54 +76,163 @@ static int __init hardlockup_panic_setup(char *str)
 	else if (!strncmp(str, "nopanic", 7))
 		hardlockup_panic = 0;
 	else if (!strncmp(str, "0", 1))
-		nmi_watchdog_user_enabled = 0;
+		watchdog_hardlockup_user_enabled = 0;
 	else if (!strncmp(str, "1", 1))
-		nmi_watchdog_user_enabled = 1;
+		watchdog_hardlockup_user_enabled = 1;
 	return 1;
 }
 __setup("nmi_watchdog=", hardlockup_panic_setup);
 
 #endif /* CONFIG_HARDLOCKUP_DETECTOR */
 
+#if defined(CONFIG_HARDLOCKUP_DETECTOR_COUNTS_HRTIMER)
+
+static DEFINE_PER_CPU(atomic_t, hrtimer_interrupts);
+static DEFINE_PER_CPU(int, hrtimer_interrupts_saved);
+static DEFINE_PER_CPU(bool, watchdog_hardlockup_warned);
+static DEFINE_PER_CPU(bool, watchdog_hardlockup_touched);
+static unsigned long watchdog_hardlockup_all_cpu_dumped;
+
+notrace void arch_touch_nmi_watchdog(void)
+{
+	/*
+	 * Using __raw here because some code paths have
+	 * preemption enabled.  If preemption is enabled
+	 * then interrupts should be enabled too, in which
+	 * case we shouldn't have to worry about the watchdog
+	 * going off.
+	 */
+	raw_cpu_write(watchdog_hardlockup_touched, true);
+}
+EXPORT_SYMBOL(arch_touch_nmi_watchdog);
+
+void watchdog_hardlockup_touch_cpu(unsigned int cpu)
+{
+	per_cpu(watchdog_hardlockup_touched, cpu) = true;
+}
+
+static bool is_hardlockup(unsigned int cpu)
+{
+	int hrint = atomic_read(&per_cpu(hrtimer_interrupts, cpu));
+
+	if (per_cpu(hrtimer_interrupts_saved, cpu) == hrint)
+		return true;
+
+	/*
+	 * NOTE: we don't need any fancy atomic_t or READ_ONCE/WRITE_ONCE
+	 * for hrtimer_interrupts_saved. hrtimer_interrupts_saved is
+	 * written/read by a single CPU.
+	 */
+	per_cpu(hrtimer_interrupts_saved, cpu) = hrint;
+
+	return false;
+}
+
+static void watchdog_hardlockup_kick(void)
+{
+	int new_interrupts;
+
+	new_interrupts = atomic_inc_return(this_cpu_ptr(&hrtimer_interrupts));
+	watchdog_buddy_check_hardlockup(new_interrupts);
+}
+
+void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs)
+{
+	if (per_cpu(watchdog_hardlockup_touched, cpu)) {
+		per_cpu(watchdog_hardlockup_touched, cpu) = false;
+		return;
+	}
+
+	/*
+	 * Check for a hardlockup by making sure the CPU's timer
+	 * interrupt is incrementing. The timer interrupt should have
+	 * fired multiple times before we overflow'd. If it hasn't
+	 * then this is a good indication the cpu is stuck
+	 */
+	if (is_hardlockup(cpu)) {
+		unsigned int this_cpu = smp_processor_id();
+		struct cpumask backtrace_mask;
+
+		cpumask_copy(&backtrace_mask, cpu_online_mask);
+
+		/* Only print hardlockups once. */
+		if (per_cpu(watchdog_hardlockup_warned, cpu))
+			return;
+
+		pr_emerg("Watchdog detected hard LOCKUP on cpu %d\n", cpu);
+		print_modules();
+		print_irqtrace_events(current);
+		if (cpu == this_cpu) {
+			if (regs)
+				show_regs(regs);
+			else
+				dump_stack();
+			cpumask_clear_cpu(cpu, &backtrace_mask);
+		} else {
+			if (trigger_single_cpu_backtrace(cpu))
+				cpumask_clear_cpu(cpu, &backtrace_mask);
+		}
+
+		/*
+		 * Perform multi-CPU dump only once to avoid multiple
+		 * hardlockups generating interleaving traces
+		 */
+		if (sysctl_hardlockup_all_cpu_backtrace &&
+		    !test_and_set_bit(0, &watchdog_hardlockup_all_cpu_dumped))
+			trigger_cpumask_backtrace(&backtrace_mask);
+
+		if (hardlockup_panic)
+			nmi_panic(regs, "Hard LOCKUP");
+
+		per_cpu(watchdog_hardlockup_warned, cpu) = true;
+	} else {
+		per_cpu(watchdog_hardlockup_warned, cpu) = false;
+	}
+}
+
+#else /* CONFIG_HARDLOCKUP_DETECTOR_COUNTS_HRTIMER */
+
+static inline void watchdog_hardlockup_kick(void) { }
+
+#endif /* !CONFIG_HARDLOCKUP_DETECTOR_COUNTS_HRTIMER */
+
 /*
- * These functions can be overridden if an architecture implements its
+ * These functions can be overridden based on the configured hardlockdup detector.
- * own hardlockup detector.
  *
- * watchdog_nmi_enable/disable can be implemented to start and stop when
+ * watchdog_hardlockup_enable/disable can be implemented to start and stop when
- * softlockup watchdog start and stop. The arch must select the
+ * softlockup watchdog start and stop. The detector must select the
  * SOFTLOCKUP_DETECTOR Kconfig.
  */
-int __weak watchdog_nmi_enable(unsigned int cpu)
+void __weak watchdog_hardlockup_enable(unsigned int cpu) { }
-{
-	hardlockup_detector_perf_enable();
-	return 0;
-}
 
-void __weak watchdog_nmi_disable(unsigned int cpu)
+void __weak watchdog_hardlockup_disable(unsigned int cpu) { }
-{
-	hardlockup_detector_perf_disable();
-}
 
-/* Return 0, if a NMI watchdog is available. Error code otherwise */
+/*
-int __weak __init watchdog_nmi_probe(void)
+ * Watchdog-detector specific API.
+ *
+ * Return 0 when hardlockup watchdog is available, negative value otherwise.
+ * Note that the negative value means that a delayed probe might
+ * succeed later.
+ */
+int __weak __init watchdog_hardlockup_probe(void)
 {
-	return hardlockup_detector_perf_init();
+	return -ENODEV;
 }
 
 /**
- * watchdog_nmi_stop - Stop the watchdog for reconfiguration
+ * watchdog_hardlockup_stop - Stop the watchdog for reconfiguration
  *
  * The reconfiguration steps are:
- * watchdog_nmi_stop();
+ * watchdog_hardlockup_stop();
  * update_variables();
- * watchdog_nmi_start();
+ * watchdog_hardlockup_start();
  */
-void __weak watchdog_nmi_stop(void) { }
+void __weak watchdog_hardlockup_stop(void) { }
 
 /**
- * watchdog_nmi_start - Start the watchdog after reconfiguration
+ * watchdog_hardlockup_start - Start the watchdog after reconfiguration
  *
- * Counterpart to watchdog_nmi_stop().
+ * Counterpart to watchdog_hardlockup_stop().
  *
  * The following variables have been updated in update_variables() and
  * contain the currently valid configuration:
@@ -133,23 +240,23 @@ void __weak watchdog_nmi_stop(void) { }
  * - watchdog_thresh
  * - watchdog_cpumask
  */
-void __weak watchdog_nmi_start(void) { }
+void __weak watchdog_hardlockup_start(void) { }
 
 /**
  * lockup_detector_update_enable - Update the sysctl enable bit
  *
- * Caller needs to make sure that the NMI/perf watchdogs are off, so this
+ * Caller needs to make sure that the hard watchdogs are off, so this
- * can't race with watchdog_nmi_disable().
+ * can't race with watchdog_hardlockup_disable().
  */
 static void lockup_detector_update_enable(void)
 {
 	watchdog_enabled = 0;
 	if (!watchdog_user_enabled)
 		return;
-	if (nmi_watchdog_available && nmi_watchdog_user_enabled)
+	if (watchdog_hardlockup_available && watchdog_hardlockup_user_enabled)
-		watchdog_enabled |= NMI_WATCHDOG_ENABLED;
+		watchdog_enabled |= WATCHDOG_HARDLOCKUP_ENABLED;
-	if (soft_watchdog_user_enabled)
+	if (watchdog_softlockup_user_enabled)
-		watchdog_enabled |= SOFT_WATCHDOG_ENABLED;
+		watchdog_enabled |= WATCHDOG_SOFTOCKUP_ENABLED;
 }
 
 #ifdef CONFIG_SOFTLOCKUP_DETECTOR
@@ -179,8 +286,6 @@ static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
 static DEFINE_PER_CPU(unsigned long, watchdog_report_ts);
 static DEFINE_PER_CPU(struct hrtimer, watchdog_hrtimer);
 static DEFINE_PER_CPU(bool, softlockup_touch_sync);
-static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts);
-static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved);
 static unsigned long soft_lockup_nmi_warn;
 
 static int __init nowatchdog_setup(char *str)
@@ -192,7 +297,7 @@ __setup("nowatchdog", nowatchdog_setup);
 
 static int __init nosoftlockup_setup(char *str)
 {
-	soft_watchdog_user_enabled = 0;
+	watchdog_softlockup_user_enabled = 0;
 	return 1;
 }
 __setup("nosoftlockup", nosoftlockup_setup);
@@ -306,7 +411,7 @@ static int is_softlockup(unsigned long touch_ts,
 			 unsigned long period_ts,
 			 unsigned long now)
 {
-	if ((watchdog_enabled & SOFT_WATCHDOG_ENABLED) && watchdog_thresh){
+	if ((watchdog_enabled & WATCHDOG_SOFTOCKUP_ENABLED) && watchdog_thresh) {
 		/* Warn about unreasonable delays. */
 		if (time_after(now, period_ts + get_softlockup_thresh()))
 			return now - touch_ts;
@@ -315,22 +420,6 @@ static int is_softlockup(unsigned long touch_ts,
 }
 
 /* watchdog detector functions */
-bool is_hardlockup(void)
-{
-	unsigned long hrint = __this_cpu_read(hrtimer_interrupts);
-
-	if (__this_cpu_read(hrtimer_interrupts_saved) == hrint)
-		return true;
-
-	__this_cpu_write(hrtimer_interrupts_saved, hrint);
-	return false;
-}
-
-static void watchdog_interrupt_count(void)
-{
-	__this_cpu_inc(hrtimer_interrupts);
-}
-
 static DEFINE_PER_CPU(struct completion, softlockup_completion);
 static DEFINE_PER_CPU(struct cpu_stop_work, softlockup_stop_work);
 
@@ -361,8 +450,7 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
 	if (!watchdog_enabled)
 		return HRTIMER_NORESTART;
 
-	/* kick the hardlockup detector */
+	watchdog_hardlockup_kick();
-	watchdog_interrupt_count();
 
 	/* kick the softlockup detector */
 	if (completion_done(this_cpu_ptr(&softlockup_completion))) {
@@ -458,7 +546,7 @@ static void watchdog_enable(unsigned int cpu)
 	complete(done);
 
 	/*
-	 * Start the timer first to prevent the NMI watchdog triggering
+	 * Start the timer first to prevent the hardlockup watchdog triggering
 	 * before the timer has a chance to fire.
 	 */
 	hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
@@ -468,9 +556,9 @@ static void watchdog_enable(unsigned int cpu)
 
 	/* Initialize timestamp */
 	update_touch_ts();
-	/* Enable the perf event */
+	/* Enable the hardlockup detector */
-	if (watchdog_enabled & NMI_WATCHDOG_ENABLED)
+	if (watchdog_enabled & WATCHDOG_HARDLOCKUP_ENABLED)
-		watchdog_nmi_enable(cpu);
+		watchdog_hardlockup_enable(cpu);
 }
 
 static void watchdog_disable(unsigned int cpu)
@@ -480,11 +568,11 @@ static void watchdog_disable(unsigned int cpu)
 	WARN_ON_ONCE(cpu != smp_processor_id());
 
 	/*
-	 * Disable the perf event first. That prevents that a large delay
+	 * Disable the hardlockup detector first. That prevents that a large
-	 * between disabling the timer and disabling the perf event causes
+	 * delay between disabling the timer and disabling the hardlockup
-	 * the perf NMI to detect a false positive.
+	 * detector causes a false positive.
 	 */
-	watchdog_nmi_disable(cpu);
+	watchdog_hardlockup_disable(cpu);
 	hrtimer_cancel(hrtimer);
 	wait_for_completion(this_cpu_ptr(&softlockup_completion));
 }
@@ -540,7 +628,7 @@ int lockup_detector_offline_cpu(unsigned int cpu)
 static void __lockup_detector_reconfigure(void)
 {
 	cpus_read_lock();
-	watchdog_nmi_stop();
+	watchdog_hardlockup_stop();
 
 	softlockup_stop_all();
 	set_sample_period();
@@ -548,7 +636,7 @@ static void __lockup_detector_reconfigure(void)
 	if (watchdog_enabled && watchdog_thresh)
 		softlockup_start_all();
 
-	watchdog_nmi_start();
+	watchdog_hardlockup_start();
 	cpus_read_unlock();
 	/*
 	 * Must be called outside the cpus locked section to prevent
@@ -589,9 +677,9 @@ static __init void lockup_detector_setup(void)
 static void __lockup_detector_reconfigure(void)
 {
 	cpus_read_lock();
-	watchdog_nmi_stop();
+	watchdog_hardlockup_stop();
 	lockup_detector_update_enable();
-	watchdog_nmi_start();
+	watchdog_hardlockup_start();
 	cpus_read_unlock();
 }
 void lockup_detector_reconfigure(void)
@@ -646,14 +734,14 @@ static void proc_watchdog_update(void)
 /*
  * common function for watchdog, nmi_watchdog and soft_watchdog parameter
  *
- * caller             | table->data points to      | 'which'
+ * caller             | table->data points to            | 'which'
- * -------------------|----------------------------|--------------------------
+ * -------------------|----------------------------------|-------------------------------
- * proc_watchdog      | watchdog_user_enabled      | NMI_WATCHDOG_ENABLED |
+ * proc_watchdog      | watchdog_user_enabled            | WATCHDOG_HARDLOCKUP_ENABLED |
- *                    |                            | SOFT_WATCHDOG_ENABLED
+ *                    |                                  | WATCHDOG_SOFTOCKUP_ENABLED
- * -------------------|----------------------------|--------------------------
+ * -------------------|----------------------------------|-------------------------------
- * proc_nmi_watchdog  | nmi_watchdog_user_enabled  | NMI_WATCHDOG_ENABLED
+ * proc_nmi_watchdog  | watchdog_hardlockup_user_enabled | WATCHDOG_HARDLOCKUP_ENABLED
- * -------------------|----------------------------|--------------------------
+ * -------------------|----------------------------------|-------------------------------
- * proc_soft_watchdog | soft_watchdog_user_enabled | SOFT_WATCHDOG_ENABLED
+ * proc_soft_watchdog | watchdog_softlockup_user_enabled | WATCHDOG_SOFTOCKUP_ENABLED
  */
 static int proc_watchdog_common(int which, struct ctl_table *table, int write,
 				void *buffer, size_t *lenp, loff_t *ppos)
@@ -685,7 +773,8 @@ static int proc_watchdog_common(int which, struct ctl_table *table, int write,
 int proc_watchdog(struct ctl_table *table, int write,
 		  void *buffer, size_t *lenp, loff_t *ppos)
 {
-	return proc_watchdog_common(NMI_WATCHDOG_ENABLED|SOFT_WATCHDOG_ENABLED,
+	return proc_watchdog_common(WATCHDOG_HARDLOCKUP_ENABLED |
+				    WATCHDOG_SOFTOCKUP_ENABLED,
 				    table, write, buffer, lenp, ppos);
 }
 
@@ -695,9 +784,9 @@ int proc_watchdog(struct ctl_table *table, int write,
 int proc_nmi_watchdog(struct ctl_table *table, int write,
 		      void *buffer, size_t *lenp, loff_t *ppos)
 {
-	if (!nmi_watchdog_available && write)
+	if (!watchdog_hardlockup_available && write)
 		return -ENOTSUPP;
-	return proc_watchdog_common(NMI_WATCHDOG_ENABLED,
+	return proc_watchdog_common(WATCHDOG_HARDLOCKUP_ENABLED,
 				    table, write, buffer, lenp, ppos);
 }
 
@@ -707,7 +796,7 @@ int proc_nmi_watchdog(struct ctl_table *table, int write,
 int proc_soft_watchdog(struct ctl_table *table, int write,
 			void *buffer, size_t *lenp, loff_t *ppos)
 {
-	return proc_watchdog_common(SOFT_WATCHDOG_ENABLED,
+	return proc_watchdog_common(WATCHDOG_SOFTOCKUP_ENABLED,
 				    table, write, buffer, lenp, ppos);
 }
 
@@ -773,15 +862,6 @@ static struct ctl_table watchdog_sysctls[] = {
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= (void *)&sixty,
 	},
-	{
-		.procname       = "nmi_watchdog",
-		.data		= &nmi_watchdog_user_enabled,
-		.maxlen		= sizeof(int),
-		.mode		= NMI_WATCHDOG_SYSCTL_PERM,
-		.proc_handler   = proc_nmi_watchdog,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
 	{
 		.procname	= "watchdog_cpumask",
 		.data		= &watchdog_cpumask_bits,
@@ -792,7 +872,7 @@ static struct ctl_table watchdog_sysctls[] = {
 #ifdef CONFIG_SOFTLOCKUP_DETECTOR
 	{
 		.procname       = "soft_watchdog",
-		.data		= &soft_watchdog_user_enabled,
+		.data		= &watchdog_softlockup_user_enabled,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler   = proc_soft_watchdog,
@@ -845,14 +925,90 @@ static struct ctl_table watchdog_sysctls[] = {
 	{}
 };
 
+static struct ctl_table watchdog_hardlockup_sysctl[] = {
+	{
+		.procname       = "nmi_watchdog",
+		.data		= &watchdog_hardlockup_user_enabled,
+		.maxlen		= sizeof(int),
+		.mode		= 0444,
+		.proc_handler   = proc_nmi_watchdog,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{}
+};
+
 static void __init watchdog_sysctl_init(void)
 {
 	register_sysctl_init("kernel", watchdog_sysctls);
+
+	if (watchdog_hardlockup_available)
+		watchdog_hardlockup_sysctl[0].mode = 0644;
+	register_sysctl_init("kernel", watchdog_hardlockup_sysctl);
 }
+
 #else
 #define watchdog_sysctl_init() do { } while (0)
 #endif /* CONFIG_SYSCTL */
 
+static void __init lockup_detector_delay_init(struct work_struct *work);
+static bool allow_lockup_detector_init_retry __initdata;
+
+static struct work_struct detector_work __initdata =
+		__WORK_INITIALIZER(detector_work, lockup_detector_delay_init);
+
+static void __init lockup_detector_delay_init(struct work_struct *work)
+{
+	int ret;
+
+	ret = watchdog_hardlockup_probe();
+	if (ret) {
+		pr_info("Delayed init of the lockup detector failed: %d\n", ret);
+		pr_info("Hard watchdog permanently disabled\n");
+		return;
+	}
+
+	allow_lockup_detector_init_retry = false;
+
+	watchdog_hardlockup_available = true;
+	lockup_detector_setup();
+}
+
+/*
+ * lockup_detector_retry_init - retry init lockup detector if possible.
+ *
+ * Retry hardlockup detector init. It is useful when it requires some
+ * functionality that has to be initialized later on a particular
+ * platform.
+ */
+void __init lockup_detector_retry_init(void)
+{
+	/* Must be called before late init calls */
+	if (!allow_lockup_detector_init_retry)
+		return;
+
+	schedule_work(&detector_work);
+}
+
+/*
+ * Ensure that optional delayed hardlockup init is proceed before
+ * the init code and memory is freed.
+ */
+static int __init lockup_detector_check(void)
+{
+	/* Prevent any later retry. */
+	allow_lockup_detector_init_retry = false;
+
+	/* Make sure no work is pending. */
+	flush_work(&detector_work);
+
+	watchdog_sysctl_init();
+
+	return 0;
+
+}
+late_initcall_sync(lockup_detector_check);
+
 void __init lockup_detector_init(void)
 {
 	if (tick_nohz_full_enabled())
@@ -861,8 +1017,10 @@ void __init lockup_detector_init(void)
 	cpumask_copy(&watchdog_cpumask,
 		     housekeeping_cpumask(HK_TYPE_TIMER));
 
-	if (!watchdog_nmi_probe())
+	if (!watchdog_hardlockup_probe())
-		nmi_watchdog_available = true;
+		watchdog_hardlockup_available = true;
+	else
+		allow_lockup_detector_init_retry = true;
+
 	lockup_detector_setup();
-	watchdog_sysctl_init();
 }

kernel/watchdog_buddy.c

@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/cpu.h>
+#include <linux/cpumask.h>
+#include <linux/kernel.h>
+#include <linux/nmi.h>
+#include <linux/percpu-defs.h>
+
+static cpumask_t __read_mostly watchdog_cpus;
+
+static unsigned int watchdog_next_cpu(unsigned int cpu)
+{
+	unsigned int next_cpu;
+
+	next_cpu = cpumask_next(cpu, &watchdog_cpus);
+	if (next_cpu >= nr_cpu_ids)
+		next_cpu = cpumask_first(&watchdog_cpus);
+
+	if (next_cpu == cpu)
+		return nr_cpu_ids;
+
+	return next_cpu;
+}
+
+int __init watchdog_hardlockup_probe(void)
+{
+	return 0;
+}
+
+void watchdog_hardlockup_enable(unsigned int cpu)
+{
+	unsigned int next_cpu;
+
+	/*
+	 * The new CPU will be marked online before the hrtimer interrupt
+	 * gets a chance to run on it. If another CPU tests for a
+	 * hardlockup on the new CPU before it has run its the hrtimer
+	 * interrupt, it will get a false positive. Touch the watchdog on
+	 * the new CPU to delay the check for at least 3 sampling periods
+	 * to guarantee one hrtimer has run on the new CPU.
+	 */
+	watchdog_hardlockup_touch_cpu(cpu);
+
+	/*
+	 * We are going to check the next CPU. Our watchdog_hrtimer
+	 * need not be zero if the CPU has already been online earlier.
+	 * Touch the watchdog on the next CPU to avoid false positive
+	 * if we try to check it in less then 3 interrupts.
+	 */
+	next_cpu = watchdog_next_cpu(cpu);
+	if (next_cpu < nr_cpu_ids)
+		watchdog_hardlockup_touch_cpu(next_cpu);
+
+	/*
+	 * Makes sure that watchdog is touched on this CPU before
+	 * other CPUs could see it in watchdog_cpus. The counter
+	 * part is in watchdog_buddy_check_hardlockup().
+	 */
+	smp_wmb();
+
+	cpumask_set_cpu(cpu, &watchdog_cpus);
+}
+
+void watchdog_hardlockup_disable(unsigned int cpu)
+{
+	unsigned int next_cpu = watchdog_next_cpu(cpu);
+
+	/*
+	 * Offlining this CPU will cause the CPU before this one to start
+	 * checking the one after this one. If this CPU just finished checking
+	 * the next CPU and updating hrtimer_interrupts_saved, and then the
+	 * previous CPU checks it within one sample period, it will trigger a
+	 * false positive. Touch the watchdog on the next CPU to prevent it.
+	 */
+	if (next_cpu < nr_cpu_ids)
+		watchdog_hardlockup_touch_cpu(next_cpu);
+
+	/*
+	 * Makes sure that watchdog is touched on the next CPU before
+	 * this CPU disappear in watchdog_cpus. The counter part is in
+	 * watchdog_buddy_check_hardlockup().
+	 */
+	smp_wmb();
+
+	cpumask_clear_cpu(cpu, &watchdog_cpus);
+}
+
+void watchdog_buddy_check_hardlockup(int hrtimer_interrupts)
+{
+	unsigned int next_cpu;
+
+	/*
+	 * Test for hardlockups every 3 samples. The sample period is
+	 *  watchdog_thresh * 2 / 5, so 3 samples gets us back to slightly over
+	 *  watchdog_thresh (over by 20%).
+	 */
+	if (hrtimer_interrupts % 3 != 0)
+		return;
+
+	/* check for a hardlockup on the next CPU */
+	next_cpu = watchdog_next_cpu(smp_processor_id());
+	if (next_cpu >= nr_cpu_ids)
+		return;
+
+	/*
+	 * Make sure that the watchdog was touched on next CPU when
+	 * watchdog_next_cpu() returned another one because of
+	 * a change in watchdog_hardlockup_enable()/disable().
+	 */
+	smp_rmb();
+
+	watchdog_hardlockup_check(next_cpu, NULL);
+}

kernel/watchdog_perf.c

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * Detect hard lockups on a system
+ * Detect hard lockups on a system using perf
  *
  * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
  *
@@ -20,28 +20,12 @@
 #include <asm/irq_regs.h>
 #include <linux/perf_event.h>
 
-static DEFINE_PER_CPU(bool, hard_watchdog_warn);
-static DEFINE_PER_CPU(bool, watchdog_nmi_touch);
 static DEFINE_PER_CPU(struct perf_event *, watchdog_ev);
 static DEFINE_PER_CPU(struct perf_event *, dead_event);
 static struct cpumask dead_events_mask;
 
-static unsigned long hardlockup_allcpu_dumped;
 static atomic_t watchdog_cpus = ATOMIC_INIT(0);
 
-notrace void arch_touch_nmi_watchdog(void)
-{
-	/*
-	 * Using __raw here because some code paths have
-	 * preemption enabled.  If preemption is enabled
-	 * then interrupts should be enabled too, in which
-	 * case we shouldn't have to worry about the watchdog
-	 * going off.
-	 */
-	raw_cpu_write(watchdog_nmi_touch, true);
-}
-EXPORT_SYMBOL(arch_touch_nmi_watchdog);
-
 #ifdef CONFIG_HARDLOCKUP_CHECK_TIMESTAMP
 static DEFINE_PER_CPU(ktime_t, last_timestamp);
 static DEFINE_PER_CPU(unsigned int, nmi_rearmed);
@@ -114,61 +98,24 @@ static void watchdog_overflow_callback(struct perf_event *event,
 	/* Ensure the watchdog never gets throttled */
 	event->hw.interrupts = 0;
 
-	if (__this_cpu_read(watchdog_nmi_touch) == true) {
-		__this_cpu_write(watchdog_nmi_touch, false);
-		return;
-	}
-
 	if (!watchdog_check_timestamp())
 		return;
 
-	/* check for a hardlockup
+	watchdog_hardlockup_check(smp_processor_id(), regs);
-	 * This is done by making sure our timer interrupt
-	 * is incrementing.  The timer interrupt should have
-	 * fired multiple times before we overflow'd.  If it hasn't
-	 * then this is a good indication the cpu is stuck
-	 */
-	if (is_hardlockup()) {
-		int this_cpu = smp_processor_id();
-
-		/* only print hardlockups once */
-		if (__this_cpu_read(hard_watchdog_warn) == true)
-			return;
-
-		pr_emerg("Watchdog detected hard LOCKUP on cpu %d\n",
-			 this_cpu);
-		print_modules();
-		print_irqtrace_events(current);
-		if (regs)
-			show_regs(regs);
-		else
-			dump_stack();
-
-		/*
-		 * Perform all-CPU dump only once to avoid multiple hardlockups
-		 * generating interleaving traces
-		 */
-		if (sysctl_hardlockup_all_cpu_backtrace &&
-				!test_and_set_bit(0, &hardlockup_allcpu_dumped))
-			trigger_allbutself_cpu_backtrace();
-
-		if (hardlockup_panic)
-			nmi_panic(regs, "Hard LOCKUP");
-
-		__this_cpu_write(hard_watchdog_warn, true);
-		return;
-	}
-
-	__this_cpu_write(hard_watchdog_warn, false);
-	return;
 }
 
 static int hardlockup_detector_event_create(void)
 {
-	unsigned int cpu = smp_processor_id();
+	unsigned int cpu;
 	struct perf_event_attr *wd_attr;
 	struct perf_event *evt;
 
+	/*
+	 * Preemption is not disabled because memory will be allocated.
+	 * Ensure CPU-locality by calling this in per-CPU kthread.
+	 */
+	WARN_ON(!is_percpu_thread());
+	cpu = raw_smp_processor_id();
 	wd_attr = &wd_hw_attr;
 	wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh);
 
@@ -185,10 +132,14 @@ static int hardlockup_detector_event_create(void)
 }
 
 /**
- * hardlockup_detector_perf_enable - Enable the local event
+ * watchdog_hardlockup_enable - Enable the local event
+ *
+ * @cpu: The CPU to enable hard lockup on.
  */
-void hardlockup_detector_perf_enable(void)
+void watchdog_hardlockup_enable(unsigned int cpu)
 {
+	WARN_ON_ONCE(cpu != smp_processor_id());
+
 	if (hardlockup_detector_event_create())
 		return;
 
@@ -200,12 +151,16 @@ void hardlockup_detector_perf_enable(void)
 }
 
 /**
- * hardlockup_detector_perf_disable - Disable the local event
+ * watchdog_hardlockup_disable - Disable the local event
+ *
+ * @cpu: The CPU to enable hard lockup on.
  */
-void hardlockup_detector_perf_disable(void)
+void watchdog_hardlockup_disable(unsigned int cpu)
 {
 	struct perf_event *event = this_cpu_read(watchdog_ev);
 
+	WARN_ON_ONCE(cpu != smp_processor_id());
+
 	if (event) {
 		perf_event_disable(event);
 		this_cpu_write(watchdog_ev, NULL);
@@ -268,7 +223,7 @@ void __init hardlockup_detector_perf_restart(void)
 
 	lockdep_assert_cpus_held();
 
-	if (!(watchdog_enabled & NMI_WATCHDOG_ENABLED))
+	if (!(watchdog_enabled & WATCHDOG_HARDLOCKUP_ENABLED))
 		return;
 
 	for_each_online_cpu(cpu) {
@@ -279,12 +234,22 @@ void __init hardlockup_detector_perf_restart(void)
 	}
 }
 
-/**
+bool __weak __init arch_perf_nmi_is_available(void)
- * hardlockup_detector_perf_init - Probe whether NMI event is available at all
- */
-int __init hardlockup_detector_perf_init(void)
 {
-	int ret = hardlockup_detector_event_create();
+	return true;
+}
+
+/**
+ * watchdog_hardlockup_probe - Probe whether NMI event is available at all
+ */
+int __init watchdog_hardlockup_probe(void)
+{
+	int ret;
+
+	if (!arch_perf_nmi_is_available())
+		return -ENODEV;
+
+	ret = hardlockup_detector_event_create();
 
 	if (ret) {
 		pr_info("Perf NMI watchdog permanently disabled\n");

lib/Kconfig.debug

@@ -1035,7 +1035,86 @@ config BOOTPARAM_SOFTLOCKUP_PANIC
 
 	  Say N if unsure.
 
+config HAVE_HARDLOCKUP_DETECTOR_BUDDY
+	bool
+	depends on SMP
+	default y
+
+#
+# Global switch whether to build a hardlockup detector at all. It is available
+# only when the architecture supports at least one implementation. There are
+# two exceptions. The hardlockup detector is never enabled on:
+#
+#	s390: it reported many false positives there
+#
+#	sparc64: has a custom implementation which is not using the common
+#		hardlockup command line options and sysctl interface.
+#
+config HARDLOCKUP_DETECTOR
+	bool "Detect Hard Lockups"
+	depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64
+	depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH
+	imply HARDLOCKUP_DETECTOR_PERF
+	imply HARDLOCKUP_DETECTOR_BUDDY
+	imply HARDLOCKUP_DETECTOR_ARCH
+	select LOCKUP_DETECTOR
+
+	help
+	  Say Y here to enable the kernel to act as a watchdog to detect
+	  hard lockups.
+
+	  Hardlockups are bugs that cause the CPU to loop in kernel mode
+	  for more than 10 seconds, without letting other interrupts have a
+	  chance to run.  The current stack trace is displayed upon detection
+	  and the system will stay locked up.
+
+#
+# Note that arch-specific variants are always preferred.
+#
+config HARDLOCKUP_DETECTOR_PREFER_BUDDY
+	bool "Prefer the buddy CPU hardlockup detector"
+	depends on HARDLOCKUP_DETECTOR
+	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY
+	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
+	help
+	  Say Y here to prefer the buddy hardlockup detector over the perf one.
+
+	  With the buddy detector, each CPU uses its softlockup hrtimer
+	  to check that the next CPU is processing hrtimer interrupts by
+	  verifying that a counter is increasing.
+
+	  This hardlockup detector is useful on systems that don't have
+	  an arch-specific hardlockup detector or if resources needed
+	  for the hardlockup detector are better used for other things.
+
 config HARDLOCKUP_DETECTOR_PERF
+	bool
+	depends on HARDLOCKUP_DETECTOR
+	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY
+	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
+	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
+
+config HARDLOCKUP_DETECTOR_BUDDY
+	bool
+	depends on HARDLOCKUP_DETECTOR
+	depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY
+	depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY
+	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
+	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
+
+config HARDLOCKUP_DETECTOR_ARCH
+	bool
+	depends on HARDLOCKUP_DETECTOR
+	depends on HAVE_HARDLOCKUP_DETECTOR_ARCH
+	help
+	  The arch-specific implementation of the hardlockup detector will
+	  be used.
+
+#
+# Both the "perf" and "buddy" hardlockup detectors count hrtimer
+# interrupts. This config enables functions managing this common code.
+#
+config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
 	bool
 	select SOFTLOCKUP_DETECTOR
 
@@ -1046,25 +1125,6 @@ config HARDLOCKUP_DETECTOR_PERF
 config HARDLOCKUP_CHECK_TIMESTAMP
 	bool
 
-#
-# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
-# lockup detector rather than the perf based detector.
-#
-config HARDLOCKUP_DETECTOR
-	bool "Detect Hard Lockups"
-	depends on DEBUG_KERNEL && !S390
-	depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
-	select LOCKUP_DETECTOR
-	select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
-	help
-	  Say Y here to enable the kernel to act as a watchdog to detect
-	  hard lockups.
-
-	  Hardlockups are bugs that cause the CPU to loop in kernel mode
-	  for more than 10 seconds, without letting other interrupts have a
-	  chance to run.  The current stack trace is displayed upon detection
-	  and the system will stay locked up.
-
 config BOOTPARAM_HARDLOCKUP_PANIC
 	bool "Panic (Reboot) On Hard Lockups"
 	depends on HARDLOCKUP_DETECTOR

lib/decompress_inflate.c

@@ -39,7 +39,7 @@ static long INIT nofill(void *buffer, unsigned long len)
 }
 
 /* Included from initramfs et al code */
-STATIC int INIT __gunzip(unsigned char *buf, long len,
+static int INIT __gunzip(unsigned char *buf, long len,
 		       long (*fill)(void*, unsigned long),
 		       long (*flush)(void*, unsigned long),
 		       unsigned char *out_buf, long out_len,

lib/decompress_unxz.c

@@ -102,6 +102,8 @@
  */
 #ifdef STATIC
 #	define XZ_PREBOOT
+#else
+#include <linux/decompress/unxz.h>
 #endif
 #ifdef __KERNEL__
 #	include <linux/decompress/mm.h>

lib/decompress_unzstd.c

@@ -69,6 +69,8 @@
 # define UNZSTD_PREBOOT
 # include "xxhash.c"
 # include "zstd/decompress_sources.h"
+#else
+#include <linux/decompress/unzstd.h>
 #endif
 
 #include <linux/decompress/mm.h>

lib/devmem_is_allowed.c

@@ -10,6 +10,7 @@
 
 #include <linux/mm.h>
 #include <linux/ioport.h>
+#include <linux/io.h>
 
 /*
  * devmem_is_allowed() checks to see if /dev/mem access to a certain address

lib/devres.c

@@ -129,7 +129,7 @@ __devm_ioremap_resource(struct device *dev, const struct resource *res,
 	BUG_ON(!dev);
 
 	if (!res || resource_type(res) != IORESOURCE_MEM) {
-		dev_err(dev, "invalid resource\n");
+		dev_err(dev, "invalid resource %pR\n", res);
 		return IOMEM_ERR_PTR(-EINVAL);
 	}
 

lib/kunit/debugfs.c

@@ -10,6 +10,7 @@
 #include <kunit/test.h>
 
 #include "string-stream.h"
+#include "debugfs.h"
 
 #define KUNIT_DEBUGFS_ROOT             "kunit"
 #define KUNIT_DEBUGFS_RESULTS          "results"

lib/zstd/common/zstd_deps.h

@@ -105,21 +105,3 @@ static uint64_t ZSTD_div64(uint64_t dividend, uint32_t divisor) {
 
 #endif /* ZSTD_DEPS_IO */
 #endif /* ZSTD_DEPS_NEED_IO */
-
-/*
- * Only requested when MSAN is enabled.
- * Need:
- * intptr_t
- */
-#ifdef ZSTD_DEPS_NEED_STDINT
-#ifndef ZSTD_DEPS_STDINT
-#define ZSTD_DEPS_STDINT
-
-/*
- * The Linux Kernel doesn't provide intptr_t, only uintptr_t, which
- * is an unsigned long.
- */
-typedef long intptr_t;
-
-#endif /* ZSTD_DEPS_STDINT */
-#endif /* ZSTD_DEPS_NEED_STDINT */

mm/sparse.c

@@ -701,7 +701,7 @@ static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages)
 	return rc;
 }
 #else
-struct page * __meminit populate_section_memmap(unsigned long pfn,
+static struct page * __meminit populate_section_memmap(unsigned long pfn,
 		unsigned long nr_pages, int nid, struct vmem_altmap *altmap,
 		struct dev_pagemap *pgmap)
 {

scripts/spelling.txt

@@ -155,6 +155,7 @@ aquired||acquired
 aquisition||acquisition
 arbitary||arbitrary
 architechture||architecture
+archtecture||architecture
 arguement||argument
 arguements||arguments
 arithmatic||arithmetic
@@ -279,6 +280,7 @@ cant'||can't
 canot||cannot
 cann't||can't
 cannnot||cannot
+capabiity||capability
 capabilites||capabilities
 capabilties||capabilities
 capabilty||capability
@@ -426,6 +428,7 @@ cotrol||control
 cound||could
 couter||counter
 coutner||counter
+creationg||creating
 cryptocraphic||cryptographic
 cummulative||cumulative
 cunter||counter
@@ -492,6 +495,7 @@ destorys||destroys
 destroied||destroyed
 detabase||database
 deteced||detected
+detecion||detection
 detectt||detect
 detroyed||destroyed
 develope||develop
@@ -513,6 +517,7 @@ diferent||different
 differrence||difference
 diffrent||different
 differenciate||differentiate
+diffreential||differential
 diffrentiate||differentiate
 difinition||definition
 digial||digital
@@ -617,6 +622,7 @@ evalute||evaluate
 evalutes||evaluates
 evalution||evaluation
 excecutable||executable
+excceed||exceed
 exceded||exceeded
 exceds||exceeds
 exceeed||exceed
@@ -632,6 +638,7 @@ existant||existent
 exixt||exist
 exsits||exists
 exlcude||exclude
+exlcuding||excluding
 exlcusive||exclusive
 exlusive||exclusive
 exmaple||example
@@ -726,6 +733,8 @@ generiously||generously
 genereate||generate
 genereted||generated
 genric||generic
+gerenal||general
+geting||getting
 globel||global
 grabing||grabbing
 grahical||graphical
@@ -899,6 +908,7 @@ iteraions||iterations
 iternations||iterations
 itertation||iteration
 itslef||itself
+ivalid||invalid
 jave||java
 jeffies||jiffies
 jumpimng||jumping
@@ -977,6 +987,7 @@ microprocesspr||microprocessor
 migrateable||migratable
 millenium||millennium
 milliseonds||milliseconds
+minimim||minimum
 minium||minimum
 minimam||minimum
 minimun||minimum
@@ -1042,6 +1053,7 @@ notifed||notified
 notity||notify
 nubmer||number
 numebr||number
+numer||number
 numner||number
 nunber||number
 obtaion||obtain
@@ -1061,6 +1073,7 @@ offet||offset
 offlaod||offload
 offloded||offloaded
 offseting||offsetting
+oflload||offload
 omited||omitted
 omiting||omitting
 omitt||omit
@@ -1105,6 +1118,7 @@ pakage||package
 paket||packet
 pallette||palette
 paln||plan
+palne||plane
 paramameters||parameters
 paramaters||parameters
 paramater||parameter
@@ -1181,12 +1195,14 @@ previsously||previously
 primative||primitive
 princliple||principle
 priorty||priority
+priting||printing
 privilaged||privileged
 privilage||privilege
 priviledge||privilege
 priviledges||privileges
 privleges||privileges
 probaly||probably
+probabalistic||probabilistic
 procceed||proceed
 proccesors||processors
 procesed||processed
@@ -1460,6 +1476,7 @@ submited||submitted
 submition||submission
 succeded||succeeded
 suceed||succeed
+succesfuly||successfully
 succesfully||successfully
 succesful||successful
 successed||succeeded
@@ -1503,6 +1520,7 @@ symetric||symmetric
 synax||syntax
 synchonized||synchronized
 sychronization||synchronization
+sychronously||synchronously
 synchronuously||synchronously
 syncronize||synchronize
 syncronized||synchronized
@@ -1532,6 +1550,7 @@ threee||three
 threshhold||threshold
 thresold||threshold
 throught||through
+tansition||transition
 trackling||tracking
 troughput||throughput
 trys||tries
@@ -1611,6 +1630,7 @@ unneccessary||unnecessary
 unnecesary||unnecessary
 unneedingly||unnecessarily
 unnsupported||unsupported
+unuspported||unsupported
 unmached||unmatched
 unprecise||imprecise
 unpriviledged||unprivileged
@@ -1657,6 +1677,7 @@ verfication||verification
 veriosn||version
 verisons||versions
 verison||version
+veritical||vertical
 verson||version
 vicefersa||vice-versa
 virtal||virtual
@@ -1677,6 +1698,7 @@ whenver||whenever
 wheter||whether
 whe||when
 wierd||weird
+wihout||without
 wiil||will
 wirte||write
 withing||within