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lockdep: Fix per-cpu static objects

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Since commit 383776fa75 ("locking/lockdep: Handle statically initialized
PER_CPU locks properly") we try to collapse per-cpu locks into a single
class by giving them all the same key. For this key we choose the canonical
address of the per-cpu object, which would be the offset into the per-cpu
area.

This has two problems:

 - there is a case where we run !0 lock->key through static_obj() and
   expect this to pass; it doesn't for canonical pointers.

 - 0 is a valid canonical address.

Cure both issues by redefining the canonical address as the address of the
per-cpu variable on the boot CPU.

Since I didn't want to rely on CPU0 being the boot-cpu, or even existing at
all, track the boot CPU in a variable.

Fixes: 383776fa75 ("locking/lockdep: Handle statically initialized PER_CPU locks properly")
Reported-by: kernel test robot <fengguang.wu@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Borislav Petkov <bp@suse.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-mm@kvack.org
Cc: wfg@linux.intel.com
Cc: kernel test robot <fengguang.wu@intel.com>
Cc: LKP <lkp@01.org>
Link: http://lkml.kernel.org/r/20170320114108.kbvcsuepem45j5cr@hirez.programming.kicks-ass.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Peter Zijlstra
2017-03-20 12:26:55 +01:00
committed by Thomas Gleixner
parent 56222b212e
commit 8ce371f984
4 changed files with 27 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
include/linux/smp.h
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@@ -120,6 +120,13 @@ extern unsigned int setup_max_cpus;
extern void __init setup_nr_cpu_ids(void);
extern void __init smp_init(void);
extern int __boot_cpu_id;
static inline int get_boot_cpu_id(void)
{
return __boot_cpu_id;
}
#else /* !SMP */
static inline void smp_send_stop(void) { }
@@ -158,6 +165,11 @@ static inline void smp_init(void) { up_late_init(); }
static inline void smp_init(void) { }
#endif
static inline int get_boot_cpu_id(void)
{
return 0;
}
#endif /* !SMP */
/*