Pull arm64 updates from Will Deacon:
"There's quite a lot of code here, but much of it is due to the
addition of a new PMU driver as well as some arm64-specific selftests
which is an area where we've traditionally been lagging a bit.
In terms of exciting features, this includes support for the Memory
Tagging Extension which narrowly missed 5.9, hopefully allowing
userspace to run with use-after-free detection in production on CPUs
that support it. Work is ongoing to integrate the feature with KASAN
for 5.11.
Another change that I'm excited about (assuming they get the hardware
right) is preparing the ASID allocator for sharing the CPU page-table
with the SMMU. Those changes will also come in via Joerg with the
IOMMU pull.
We do stray outside of our usual directories in a few places, mostly
due to core changes required by MTE. Although much of this has been
Acked, there were a couple of places where we unfortunately didn't get
any review feedback.
Other than that, we ran into a handful of minor conflicts in -next,
but nothing that should post any issues.
Summary:
- Userspace support for the Memory Tagging Extension introduced by
Armv8.5. Kernel support (via KASAN) is likely to follow in 5.11.
- Selftests for MTE, Pointer Authentication and FPSIMD/SVE context
switching.
- Fix and subsequent rewrite of our Spectre mitigations, including
the addition of support for PR_SPEC_DISABLE_NOEXEC.
- Support for the Armv8.3 Pointer Authentication enhancements.
- Support for ASID pinning, which is required when sharing
page-tables with the SMMU.
- MM updates, including treating flush_tlb_fix_spurious_fault() as a
no-op.
- Perf/PMU driver updates, including addition of the ARM CMN PMU
driver and also support to handle CPU PMU IRQs as NMIs.
- Allow prefetchable PCI BARs to be exposed to userspace using normal
non-cacheable mappings.
- Implementation of ARCH_STACKWALK for unwinding.
- Improve reporting of unexpected kernel traps due to BPF JIT
failure.
- Improve robustness of user-visible HWCAP strings and their
corresponding numerical constants.
- Removal of TEXT_OFFSET.
- Removal of some unused functions, parameters and prototypes.
- Removal of MPIDR-based topology detection in favour of firmware
description.
- Cleanups to handling of SVE and FPSIMD register state in
preparation for potential future optimisation of handling across
syscalls.
- Cleanups to the SDEI driver in preparation for support in KVM.
- Miscellaneous cleanups and refactoring work"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (148 commits)
Revert "arm64: initialize per-cpu offsets earlier"
arm64: random: Remove no longer needed prototypes
arm64: initialize per-cpu offsets earlier
kselftest/arm64: Check mte tagged user address in kernel
kselftest/arm64: Verify KSM page merge for MTE pages
kselftest/arm64: Verify all different mmap MTE options
kselftest/arm64: Check forked child mte memory accessibility
kselftest/arm64: Verify mte tag inclusion via prctl
kselftest/arm64: Add utilities and a test to validate mte memory
perf: arm-cmn: Fix conversion specifiers for node type
perf: arm-cmn: Fix unsigned comparison to less than zero
arm64: dbm: Invalidate local TLB when setting TCR_EL1.HD
arm64: mm: Make flush_tlb_fix_spurious_fault() a no-op
arm64: Add support for PR_SPEC_DISABLE_NOEXEC prctl() option
arm64: Pull in task_stack_page() to Spectre-v4 mitigation code
KVM: arm64: Allow patching EL2 vectors even with KASLR is not enabled
arm64: Get rid of arm64_ssbd_state
KVM: arm64: Convert ARCH_WORKAROUND_2 to arm64_get_spectre_v4_state()
KVM: arm64: Get rid of kvm_arm_have_ssbd()
KVM: arm64: Simplify handling of ARCH_WORKAROUND_2
...
This prepares for the future work to trigger early cow on pinned pages
during fork().
No functional change intended.
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm: fix memory to node bad links in sysfs", v3.
Sometimes, firmware may expose interleaved memory layout like this:
Early memory node ranges
node 1: [mem 0x0000000000000000-0x000000011fffffff]
node 2: [mem 0x0000000120000000-0x000000014fffffff]
node 1: [mem 0x0000000150000000-0x00000001ffffffff]
node 0: [mem 0x0000000200000000-0x000000048fffffff]
node 2: [mem 0x0000000490000000-0x00000007ffffffff]
In that case, we can see memory blocks assigned to multiple nodes in
sysfs:
$ ls -l /sys/devices/system/memory/memory21
total 0
lrwxrwxrwx 1 root root 0 Aug 24 05:27 node1 -> ../../node/node1
lrwxrwxrwx 1 root root 0 Aug 24 05:27 node2 -> ../../node/node2
-rw-r--r-- 1 root root 65536 Aug 24 05:27 online
-r--r--r-- 1 root root 65536 Aug 24 05:27 phys_device
-r--r--r-- 1 root root 65536 Aug 24 05:27 phys_index
drwxr-xr-x 2 root root 0 Aug 24 05:27 power
-r--r--r-- 1 root root 65536 Aug 24 05:27 removable
-rw-r--r-- 1 root root 65536 Aug 24 05:27 state
lrwxrwxrwx 1 root root 0 Aug 24 05:25 subsystem -> ../../../../bus/memory
-rw-r--r-- 1 root root 65536 Aug 24 05:25 uevent
-r--r--r-- 1 root root 65536 Aug 24 05:27 valid_zones
The same applies in the node's directory with a memory21 link in both
the node1 and node2's directory.
This is wrong but doesn't prevent the system to run. However when
later, one of these memory blocks is hot-unplugged and then hot-plugged,
the system is detecting an inconsistency in the sysfs layout and a
BUG_ON() is raised:
kernel BUG at /Users/laurent/src/linux-ppc/mm/memory_hotplug.c:1084!
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
Modules linked in: rpadlpar_io rpaphp pseries_rng rng_core vmx_crypto gf128mul binfmt_misc ip_tables x_tables xfs libcrc32c crc32c_vpmsum autofs4
CPU: 8 PID: 10256 Comm: drmgr Not tainted 5.9.0-rc1+ #25
Call Trace:
add_memory_resource+0x23c/0x340 (unreliable)
__add_memory+0x5c/0xf0
dlpar_add_lmb+0x1b4/0x500
dlpar_memory+0x1f8/0xb80
handle_dlpar_errorlog+0xc0/0x190
dlpar_store+0x198/0x4a0
kobj_attr_store+0x30/0x50
sysfs_kf_write+0x64/0x90
kernfs_fop_write+0x1b0/0x290
vfs_write+0xe8/0x290
ksys_write+0xdc/0x130
system_call_exception+0x160/0x270
system_call_common+0xf0/0x27c
This has been seen on PowerPC LPAR.
The root cause of this issue is that when node's memory is registered,
the range used can overlap another node's range, thus the memory block
is registered to multiple nodes in sysfs.
There are two issues here:
(a) The sysfs memory and node's layouts are broken due to these
multiple links
(b) The link errors in link_mem_sections() should not lead to a system
panic.
To address (a) register_mem_sect_under_node should not rely on the
system state to detect whether the link operation is triggered by a hot
plug operation or not. This is addressed by the patches 1 and 2 of this
series.
Issue (b) will be addressed separately.
This patch (of 2):
The memmap_context enum is used to detect whether a memory operation is
due to a hot-add operation or happening at boot time.
Make it general to the hotplug operation and rename it as
meminit_context.
There is no functional change introduced by this patch
Suggested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Scott Cheloha <cheloha@linux.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200915094143.79181-1-ldufour@linux.ibm.com
Link: https://lkml.kernel.org/r/20200915132624.9723-1-ldufour@linux.ibm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 2a9127fcf2 ("mm: rewrite wait_on_page_bit_common() logic") made
the page locking entirely fair, in that if a waiter came in while the
lock was held, the lock would be transferred to the lockers strictly in
order.
That was intended to finally get rid of the long-reported watchdog
failures that involved the page lock under extreme load, where a process
could end up waiting essentially forever, as other page lockers stole
the lock from under it.
It also improved some benchmarks, but it ended up causing huge
performance regressions on others, simply because fair lock behavior
doesn't end up giving out the lock as aggressively, causing better
worst-case latency, but potentially much worse average latencies and
throughput.
Instead of reverting that change entirely, this introduces a controlled
amount of unfairness, with a sysctl knob to tune it if somebody needs
to. But the default value should hopefully be good for any normal load,
allowing a few rounds of lock stealing, but enforcing the strict
ordering before the lock has been stolen too many times.
There is also a hint from Matthieu Baerts that the fair page coloring
may end up exposing an ABBA deadlock that is hidden by the usual
optimistic lock stealing, and while the unfairness doesn't fix the
fundamental issue (and I'm still looking at that), it avoids it in
practice.
The amount of unfairness can be modified by writing a new value to the
'sysctl_page_lock_unfairness' variable (default value of 5, exposed
through /proc/sys/vm/page_lock_unfairness), but that is hopefully
something we'd use mainly for debugging rather than being necessary for
any deep system tuning.
This whole issue has exposed just how critical the page lock can be, and
how contended it gets under certain locks. And the main contention
doesn't really seem to be anything related to IO (which was the origin
of this lock), but for things like just verifying that the page file
mapping is stable while faulting in the page into a page table.
Link: https://lore.kernel.org/linux-fsdevel/ed8442fd-6f54-dd84-cd4a-941e8b7ee603@MichaelLarabel.com/
Link: https://www.phoronix.com/scan.php?page=article&item=linux-50-59&num=1
Link: https://lore.kernel.org/linux-fsdevel/c560a38d-8313-51fb-b1ec-e904bd8836bc@tessares.net/
Reported-and-tested-by: Michael Larabel <Michael@michaellarabel.com>
Tested-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Chris Mason <clm@fb.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To enable tagging on a memory range, the user must explicitly opt in via
a new PROT_MTE flag passed to mmap() or mprotect(). Since this is a new
memory type in the AttrIndx field of a pte, simplify the or'ing of these
bits over the protection_map[] attributes by making MT_NORMAL index 0.
There are two conditions for arch_vm_get_page_prot() to return the
MT_NORMAL_TAGGED memory type: (1) the user requested it via PROT_MTE,
registered as VM_MTE in the vm_flags, and (2) the vma supports MTE,
decided during the mmap() call (only) and registered as VM_MTE_ALLOWED.
arch_calc_vm_prot_bits() is responsible for registering the user request
as VM_MTE. The newly introduced arch_calc_vm_flag_bits() sets
VM_MTE_ALLOWED if the mapping is MAP_ANONYMOUS. An MTE-capable
filesystem (RAM-based) may be able to set VM_MTE_ALLOWED during its
mmap() file ops call.
In addition, update VM_DATA_DEFAULT_FLAGS to allow mprotect(PROT_MTE) on
stack or brk area.
The Linux mmap() syscall currently ignores unknown PROT_* flags. In the
presence of MTE, an mmap(PROT_MTE) on a file which does not support MTE
will not report an error and the memory will not be mapped as Normal
Tagged. For consistency, mprotect(PROT_MTE) will not report an error
either if the memory range does not support MTE. Two subsequent patches
in the series will propose tightening of this behaviour.
Co-developed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Pull powerpc fixes from Michael Ellerman:
- Revert our removal of PROT_SAO, at least one user expressed an
interest in using it on Power9. Instead don't allow it to be used in
guests unless enabled explicitly at compile time.
- A fix for a crash introduced by a recent change to FP handling.
- Revert a change to our idle code that left Power10 with no idle
support.
- One minor fix for the new scv system call path to set PPR.
- Fix a crash in our "generic" PMU if branch stack events were enabled.
- A fix for the IMC PMU, to correctly identify host kernel samples.
- The ADB_PMU powermac code was found to be incompatible with
VMAP_STACK, so make them incompatible in Kconfig until the code can
be fixed.
- A build fix in drivers/video/fbdev/controlfb.c, and a documentation
fix.
Thanks to Alexey Kardashevskiy, Athira Rajeev, Christophe Leroy,
Giuseppe Sacco, Madhavan Srinivasan, Milton Miller, Nicholas Piggin,
Pratik Rajesh Sampat, Randy Dunlap, Shawn Anastasio, Vaidyanathan
Srinivasan.
* tag 'powerpc-5.9-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/32s: Disable VMAP stack which CONFIG_ADB_PMU
Revert "powerpc/powernv/idle: Replace CPU feature check with PVR check"
powerpc/perf: Fix reading of MSR[HV/PR] bits in trace-imc
powerpc/perf: Fix crashes with generic_compat_pmu & BHRB
powerpc/64s: Fix crash in load_fp_state() due to fpexc_mode
powerpc/64s: scv entry should set PPR
Documentation/powerpc: fix malformed table in syscall64-abi
video: fbdev: controlfb: Fix build for COMPILE_TEST=y && PPC_PMAC=n
selftests/powerpc: Update PROT_SAO test to skip ISA 3.1
powerpc/64s: Disallow PROT_SAO in LPARs by default
Revert "powerpc/64s: Remove PROT_SAO support"
BUG: KCSAN: data-race in page_cpupid_xchg_last / put_page
write (marked) to 0xfffffc0d48ec1a00 of 8 bytes by task 91442 on cpu 3:
page_cpupid_xchg_last+0x51/0x80
page_cpupid_xchg_last at mm/mmzone.c:109 (discriminator 11)
wp_page_reuse+0x3e/0xc0
wp_page_reuse at mm/memory.c:2453
do_wp_page+0x472/0x7b0
do_wp_page at mm/memory.c:2798
__handle_mm_fault+0xcb0/0xd00
handle_pte_fault at mm/memory.c:4049
(inlined by) __handle_mm_fault at mm/memory.c:4163
handle_mm_fault+0xfc/0x2f0
handle_mm_fault at mm/memory.c:4200
do_page_fault+0x263/0x6f9
do_user_addr_fault at arch/x86/mm/fault.c:1465
(inlined by) do_page_fault at arch/x86/mm/fault.c:1539
page_fault+0x34/0x40
read to 0xfffffc0d48ec1a00 of 8 bytes by task 94817 on cpu 69:
put_page+0x15a/0x1f0
page_zonenum at include/linux/mm.h:923
(inlined by) is_zone_device_page at include/linux/mm.h:929
(inlined by) page_is_devmap_managed at include/linux/mm.h:948
(inlined by) put_page at include/linux/mm.h:1023
wp_page_copy+0x571/0x930
wp_page_copy at mm/memory.c:2615
do_wp_page+0x107/0x7b0
__handle_mm_fault+0xcb0/0xd00
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40
Reported by Kernel Concurrency Sanitizer on:
CPU: 69 PID: 94817 Comm: systemd-udevd Tainted: G W O L 5.5.0-next-20200204+ #6
Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019
A page never changes its zone number. The zone number happens to be
stored in the same word as other bits which are modified, but the zone
number bits will never be modified by any other write, so it can accept
a reload of the zone bits after an intervening write and it don't need
to use READ_ONCE(). Thus, annotate this data race using
ASSERT_EXCLUSIVE_BITS() to also assert that there are no concurrent
writes to it.
Suggested-by: Marco Elver <elver@google.com>
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Link: http://lkml.kernel.org/r/1581619089-14472-1-git-send-email-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge misc updates from Andrew Morton:
- a few MM hotfixes
- kthread, tools, scripts, ntfs and ocfs2
- some of MM
Subsystems affected by this patch series: kthread, tools, scripts, ntfs,
ocfs2 and mm (hofixes, pagealloc, slab-generic, slab, slub, kcsan,
debug, pagecache, gup, swap, shmem, memcg, pagemap, mremap, mincore,
sparsemem, vmalloc, kasan, pagealloc, hugetlb and vmscan).
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (162 commits)
mm: vmscan: consistent update to pgrefill
mm/vmscan.c: fix typo
khugepaged: khugepaged_test_exit() check mmget_still_valid()
khugepaged: retract_page_tables() remember to test exit
khugepaged: collapse_pte_mapped_thp() protect the pmd lock
khugepaged: collapse_pte_mapped_thp() flush the right range
mm/hugetlb: fix calculation of adjust_range_if_pmd_sharing_possible
mm: thp: replace HTTP links with HTTPS ones
mm/page_alloc: fix memalloc_nocma_{save/restore} APIs
mm/page_alloc.c: skip setting nodemask when we are in interrupt
mm/page_alloc: fallbacks at most has 3 elements
mm/page_alloc: silence a KASAN false positive
mm/page_alloc.c: remove unnecessary end_bitidx for [set|get]_pfnblock_flags_mask()
mm/page_alloc.c: simplify pageblock bitmap access
mm/page_alloc.c: extract the common part in pfn_to_bitidx()
mm/page_alloc.c: replace the definition of NR_MIGRATETYPE_BITS with PB_migratetype_bits
mm/shuffle: remove dynamic reconfiguration
mm/memory_hotplug: document why shuffle_zone() is relevant
mm/page_alloc: remove nr_free_pagecache_pages()
mm: remove vm_total_pages
...
After removal of CONFIG_HAVE_MEMBLOCK_NODE_MAP we have two equivalent
functions that call memory_present() for each region in memblock.memory:
sparse_memory_present_with_active_regions() and membocks_present().
Moreover, all architectures have a call to either of these functions
preceding the call to sparse_init() and in the most cases they are called
one after the other.
Mark the regions from memblock.memory as present during sparce_init() by
making sparse_init() call memblocks_present(), make memblocks_present()
and memory_present() functions static and remove redundant
sparse_memory_present_with_active_regions() function.
Also remove no longer required HAVE_MEMORY_PRESENT configuration option.
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200712083130.22919-1-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The current split between do_mmap() and do_mmap_pgoff() was introduced in
commit 1fcfd8db7f ("mm, mpx: add "vm_flags_t vm_flags" arg to
do_mmap_pgoff()") to support MPX.
The wrapper function do_mmap_pgoff() always passed 0 as the value of the
vm_flags argument to do_mmap(). However, MPX support has subsequently
been removed from the kernel and there were no more direct callers of
do_mmap(); all calls were going via do_mmap_pgoff().
Simplify the code by removing do_mmap_pgoff() and changing all callers to
directly call do_mmap(), which now no longer takes a vm_flags argument.
Signed-off-by: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: http://lkml.kernel.org/r/20200727194109.1371462-1-pcc@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When checking a performance change for will-it-scale scalability mmap test
[1], we found very high lock contention for spinlock of percpu counter
'vm_committed_as':
94.14% 0.35% [kernel.kallsyms] [k] _raw_spin_lock_irqsave
48.21% _raw_spin_lock_irqsave;percpu_counter_add_batch;__vm_enough_memory;mmap_region;do_mmap;
45.91% _raw_spin_lock_irqsave;percpu_counter_add_batch;__do_munmap;
Actually this heavy lock contention is not always necessary. The
'vm_committed_as' needs to be very precise when the strict
OVERCOMMIT_NEVER policy is set, which requires a rather small batch number
for the percpu counter.
So keep 'batch' number unchanged for strict OVERCOMMIT_NEVER policy, and
lift it to 64X for OVERCOMMIT_ALWAYS and OVERCOMMIT_GUESS policies. Also
add a sysctl handler to adjust it when the policy is reconfigured.
Benchmark with the same testcase in [1] shows 53% improvement on a 8C/16T
desktop, and 2097%(20X) on a 4S/72C/144T server. We tested with test
platforms in 0day (server, desktop and laptop), and 80%+ platforms shows
improvements with that test. And whether it shows improvements depends on
if the test mmap size is bigger than the batch number computed.
And if the lift is 16X, 1/3 of the platforms will show improvements,
though it should help the mmap/unmap usage generally, as Michal Hocko
mentioned:
: I believe that there are non-synthetic worklaods which would benefit from
: a larger batch. E.g. large in memory databases which do large mmaps
: during startups from multiple threads.
[1] https://lore.kernel.org/lkml/20200305062138.GI5972@shao2-debian/
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Qian Cai <cai@lca.pw>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: kernel test robot <rong.a.chen@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/1589611660-89854-4-git-send-email-feng.tang@intel.com
Link: http://lkml.kernel.org/r/1592725000-73486-4-git-send-email-feng.tang@intel.com
Link: http://lkml.kernel.org/r/1594389708-60781-5-git-send-email-feng.tang@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If a compound page is being split while dump_page() is being run on that
page, we can end up calling compound_mapcount() on a page that is no
longer compound. This leads to a crash (already seen at least once in the
field), due to the VM_BUG_ON_PAGE() assertion inside compound_mapcount().
(The above is from Matthew Wilcox's analysis of Qian Cai's bug report.)
A similar problem is possible, via compound_pincount() instead of
compound_mapcount().
In order to avoid this kind of crash, make dump_page() slightly more
robust, by providing a pair of simpler routines that don't contain
assertions: head_mapcount() and head_pincount().
For debug tools, we don't want to go *too* far in this direction, but this
is a simple small fix, and the crash has already been seen, so it's a good
trade-off.
Reported-by: Qian Cai <cai@lca.pw>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Link: http://lkml.kernel.org/r/20200804214807.169256-1-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ISA v3.1 does not support the SAO storage control attribute required to
implement PROT_SAO. PROT_SAO was used by specialised system software
(Lx86) that has been discontinued for about 7 years, and is not thought
to be used elsewhere, so removal should not cause problems.
We rather remove it than keep support for older processors, because
live migrating guest partitions to newer processors may not be possible
if SAO is in use (or worse allowed with silent races).
- PROT_SAO stays in the uapi header so code using it would still build.
- arch_validate_prot() is removed, the generic version rejects PROT_SAO
so applications would get a failure at mmap() time.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Drop KVM change for the time being]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200703011958.1166620-3-npiggin@gmail.com
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by this
change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
[akpm@linux-foundation.org: fix build]
Signed-off-by: chenqiwu <chenqiwu@xiaomi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Baoquan He <bhe@redhat.com>
Link: http://lkml.kernel.org/r/1586599916-15456-1-git-send-email-qiwuchen55@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge more updates from Andrew Morton:
"More mm/ work, plenty more to come
Subsystems affected by this patch series: slub, memcg, gup, kasan,
pagealloc, hugetlb, vmscan, tools, mempolicy, memblock, hugetlbfs,
thp, mmap, kconfig"
* akpm: (131 commits)
arm64: mm: use ARCH_HAS_DEBUG_WX instead of arch defined
x86: mm: use ARCH_HAS_DEBUG_WX instead of arch defined
riscv: support DEBUG_WX
mm: add DEBUG_WX support
drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup
mm/thp: rename pmd_mknotpresent() as pmd_mkinvalid()
powerpc/mm: drop platform defined pmd_mknotpresent()
mm: thp: don't need to drain lru cache when splitting and mlocking THP
hugetlbfs: get unmapped area below TASK_UNMAPPED_BASE for hugetlbfs
sparc32: register memory occupied by kernel as memblock.memory
include/linux/memblock.h: fix minor typo and unclear comment
mm, mempolicy: fix up gup usage in lookup_node
tools/vm/page_owner_sort.c: filter out unneeded line
mm: swap: memcg: fix memcg stats for huge pages
mm: swap: fix vmstats for huge pages
mm: vmscan: limit the range of LRU type balancing
mm: vmscan: reclaim writepage is IO cost
mm: vmscan: determine anon/file pressure balance at the reclaim root
mm: balance LRU lists based on relative thrashing
mm: only count actual rotations as LRU reclaim cost
...
Some architectures (e.g. ARC) have the ZONE_HIGHMEM zone below the
ZONE_NORMAL. Allowing free_area_init() parse max_zone_pfn array even it
is sorted in descending order allows using free_area_init() on such
architectures.
Add top -> down traversal of max_zone_pfn array in free_area_init() and
use the latter in ARC node/zone initialization.
[rppt@kernel.org: ARC fix]
Link: http://lkml.kernel.org/r/20200504153901.GM14260@kernel.org
[rppt@linux.ibm.com: arc: free_area_init(): take into account PAE40 mode]
Link: http://lkml.kernel.org/r/20200507205900.GH683243@linux.ibm.com
[akpm@linux-foundation.org: declare arch_has_descending_max_zone_pfns()]
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Hoan Tran <hoan@os.amperecomputing.com> [arm64]
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Guenter Roeck <linux@roeck-us.net>
Link: http://lkml.kernel.org/r/20200412194859.12663-18-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
