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Merge tag 'for-linus-5.9-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from Juergen Gross:
"A small series for fixing a problem with Xen PVH guests when running
as backends (e.g. as dom0).
Mapping other guests' memory is now working via ZONE_DEVICE, thus not
requiring to abuse the memory hotplug functionality for that purpose"
* tag 'for-linus-5.9-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen: add helpers to allocate unpopulated memory
memremap: rename MEMORY_DEVICE_DEVDAX to MEMORY_DEVICE_GENERIC
xen/balloon: add header guard
Merge misc fixes from Andrew Morton:
"19 patches.
Subsystems affected by this patch series: MAINTAINERS, ipc, fork,
checkpatch, lib, and mm (memcg, slub, pagemap, madvise, migration,
hugetlb)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
include/linux/log2.h: add missing () around n in roundup_pow_of_two()
mm/khugepaged.c: fix khugepaged's request size in collapse_file
mm/hugetlb: fix a race between hugetlb sysctl handlers
mm/hugetlb: try preferred node first when alloc gigantic page from cma
mm/migrate: preserve soft dirty in remove_migration_pte()
mm/migrate: remove unnecessary is_zone_device_page() check
mm/rmap: fixup copying of soft dirty and uffd ptes
mm/migrate: fixup setting UFFD_WP flag
mm: madvise: fix vma user-after-free
checkpatch: fix the usage of capture group ( ... )
fork: adjust sysctl_max_threads definition to match prototype
ipc: adjust proc_ipc_sem_dointvec definition to match prototype
mm: track page table modifications in __apply_to_page_range()
MAINTAINERS: IA64: mark Status as Odd Fixes only
MAINTAINERS: add LLVM maintainers
MAINTAINERS: update Cavium/Marvell entries
mm: slub: fix conversion of freelist_corrupted()
mm: memcg: fix memcg reclaim soft lockup
memcg: fix use-after-free in uncharge_batch
collapse_file() in khugepaged passes PAGE_SIZE as the number of pages to
be read to page_cache_sync_readahead(). The intent was probably to read
a single page. Fix it to use the number of pages to the end of the
window instead.
Fixes: 99cb0dbd47 ("mm,thp: add read-only THP support for (non-shmem) FS")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Yang Shi <shy828301@gmail.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Eric Biggers <ebiggers@google.com>
Link: https://lkml.kernel.org/r/20200903140844.14194-2-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is a race between the assignment of `table->data` and write value
to the pointer of `table->data` in the __do_proc_doulongvec_minmax() on
the other thread.
CPU0: CPU1:
proc_sys_write
hugetlb_sysctl_handler proc_sys_call_handler
hugetlb_sysctl_handler_common hugetlb_sysctl_handler
table->data = &tmp; hugetlb_sysctl_handler_common
table->data = &tmp;
proc_doulongvec_minmax
do_proc_doulongvec_minmax sysctl_head_finish
__do_proc_doulongvec_minmax unuse_table
i = table->data;
*i = val; // corrupt CPU1's stack
Fix this by duplicating the `table`, and only update the duplicate of
it. And introduce a helper of proc_hugetlb_doulongvec_minmax() to
simplify the code.
The following oops was seen:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
Code: Bad RIP value.
...
Call Trace:
? set_max_huge_pages+0x3da/0x4f0
? alloc_pool_huge_page+0x150/0x150
? proc_doulongvec_minmax+0x46/0x60
? hugetlb_sysctl_handler_common+0x1c7/0x200
? nr_hugepages_store+0x20/0x20
? copy_fd_bitmaps+0x170/0x170
? hugetlb_sysctl_handler+0x1e/0x20
? proc_sys_call_handler+0x2f1/0x300
? unregister_sysctl_table+0xb0/0xb0
? __fd_install+0x78/0x100
? proc_sys_write+0x14/0x20
? __vfs_write+0x4d/0x90
? vfs_write+0xef/0x240
? ksys_write+0xc0/0x160
? __ia32_sys_read+0x50/0x50
? __close_fd+0x129/0x150
? __x64_sys_write+0x43/0x50
? do_syscall_64+0x6c/0x200
? entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: e5ff215941 ("hugetlb: multiple hstates for multiple page sizes")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20200828031146.43035-1-songmuchun@bytedance.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit cf11e85fc0 ("mm: hugetlb: optionally allocate gigantic
hugepages using cma"), the gigantic page would be allocated from node
which is not the preferred node, although there are pages available from
that node. The reason is that the nid parameter has been ignored in
alloc_gigantic_page().
Besides, the __GFP_THISNODE also need be checked if user required to
alloc only from the preferred node.
After this patch, the preferred node is tried first before other allowed
nodes, and don't try to allocate from other nodes if __GFP_THISNODE is
specified. If user don't specify the preferred node, the current node
will be used as preferred node, which makes sure consistent behavior of
allocating gigantic and non-gigantic hugetlb page.
Fixes: cf11e85fc0 ("mm: hugetlb: optionally allocate gigantic hugepages using cma")
Signed-off-by: Li Xinhai <lixinhai.lxh@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Link: https://lkml.kernel.org/r/20200902025016.697260-1-lixinhai.lxh@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The code to remove a migration PTE and replace it with a device private
PTE was not copying the soft dirty bit from the migration entry. This
could lead to page contents not being marked dirty when faulting the page
back from device private memory.
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Bharata B Rao <bharata@linux.ibm.com>
Link: https://lkml.kernel.org/r/20200831212222.22409-3-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm/migrate: preserve soft dirty in remove_migration_pte()".
I happened to notice this from code inspection after seeing Alistair
Popple's patch ("mm/rmap: Fixup copying of soft dirty and uffd ptes").
This patch (of 2):
The check for is_zone_device_page() and is_device_private_page() is
unnecessary since the latter is sufficient to determine if the page is a
device private page. Simplify the code for easier reading.
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Bharata B Rao <bharata@linux.ibm.com>
Link: https://lkml.kernel.org/r/20200831212222.22409-1-rcampbell@nvidia.com
Link: https://lkml.kernel.org/r/20200831212222.22409-2-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
During memory migration a pte is temporarily replaced with a migration
swap pte. Some pte bits from the existing mapping such as the soft-dirty
and uffd write-protect bits are preserved by copying these to the
temporary migration swap pte.
However these bits are not stored at the same location for swap and
non-swap ptes. Therefore testing these bits requires using the
appropriate helper function for the given pte type.
Unfortunately several code locations were found where the wrong helper
function is being used to test soft_dirty and uffd_wp bits which leads to
them getting incorrectly set or cleared during page-migration.
Fix these by using the correct tests based on pte type.
Fixes: a5430dda8a ("mm/migrate: support un-addressable ZONE_DEVICE page in migration")
Fixes: 8c3328f1f3 ("mm/migrate: migrate_vma() unmap page from vma while collecting pages")
Fixes: f45ec5ff16 ("userfaultfd: wp: support swap and page migration")
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Alistair Popple <alistair@popple.id.au>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200825064232.10023-2-alistair@popple.id.au
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit f45ec5ff16 ("userfaultfd: wp: support swap and page migration")
introduced support for tracking the uffd wp bit during page migration.
However the non-swap PTE variant was used to set the flag for zone device
private pages which are a type of swap page.
This leads to corruption of the swap offset if the original PTE has the
uffd_wp flag set.
Fixes: f45ec5ff16 ("userfaultfd: wp: support swap and page migration")
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Link: https://lkml.kernel.org/r/20200825064232.10023-1-alistair@popple.id.au
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 52f2347808 ("mm/slub.c: fix corrupted freechain in
deactivate_slab()") suffered an update when picked up from LKML [1].
Specifically, relocating 'freelist = NULL' into 'freelist_corrupted()'
created a no-op statement. Fix it by sticking to the behavior intended
in the original patch [1]. In addition, make freelist_corrupted()
immune to passing NULL instead of &freelist.
The issue has been spotted via static analysis and code review.
[1] https://lore.kernel.org/linux-mm/20200331031450.12182-1-dongli.zhang@oracle.com/
Fixes: 52f2347808 ("mm/slub.c: fix corrupted freechain in deactivate_slab()")
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Dongli Zhang <dongli.zhang@oracle.com>
Cc: Joe Jin <joe.jin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200824130643.10291-1-erosca@de.adit-jv.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We've met softlockup with "CONFIG_PREEMPT_NONE=y", when the target memcg
doesn't have any reclaimable memory.
It can be easily reproduced as below:
watchdog: BUG: soft lockup - CPU#0 stuck for 111s![memcg_test:2204]
CPU: 0 PID: 2204 Comm: memcg_test Not tainted 5.9.0-rc2+ #12
Call Trace:
shrink_lruvec+0x49f/0x640
shrink_node+0x2a6/0x6f0
do_try_to_free_pages+0xe9/0x3e0
try_to_free_mem_cgroup_pages+0xef/0x1f0
try_charge+0x2c1/0x750
mem_cgroup_charge+0xd7/0x240
__add_to_page_cache_locked+0x2fd/0x370
add_to_page_cache_lru+0x4a/0xc0
pagecache_get_page+0x10b/0x2f0
filemap_fault+0x661/0xad0
ext4_filemap_fault+0x2c/0x40
__do_fault+0x4d/0xf9
handle_mm_fault+0x1080/0x1790
It only happens on our 1-vcpu instances, because there's no chance for
oom reaper to run to reclaim the to-be-killed process.
Add a cond_resched() at the upper shrink_node_memcgs() to solve this
issue, this will mean that we will get a scheduling point for each memcg
in the reclaimed hierarchy without any dependency on the reclaimable
memory in that memcg thus making it more predictable.
Suggested-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Xunlei Pang <xlpang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Chris Down <chris@chrisdown.name>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: http://lkml.kernel.org/r/1598495549-67324-1-git-send-email-xlpang@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
syzbot has reported an use-after-free in the uncharge_batch path
BUG: KASAN: use-after-free in instrument_atomic_write include/linux/instrumented.h:71 [inline]
BUG: KASAN: use-after-free in atomic64_sub_return include/asm-generic/atomic-instrumented.h:970 [inline]
BUG: KASAN: use-after-free in atomic_long_sub_return include/asm-generic/atomic-long.h:113 [inline]
BUG: KASAN: use-after-free in page_counter_cancel mm/page_counter.c:54 [inline]
BUG: KASAN: use-after-free in page_counter_uncharge+0x3d/0xc0 mm/page_counter.c:155
Write of size 8 at addr ffff8880371c0148 by task syz-executor.0/9304
CPU: 0 PID: 9304 Comm: syz-executor.0 Not tainted 5.8.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1f0/0x31e lib/dump_stack.c:118
print_address_description+0x66/0x620 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report+0x132/0x1d0 mm/kasan/report.c:530
check_memory_region_inline mm/kasan/generic.c:183 [inline]
check_memory_region+0x2b5/0x2f0 mm/kasan/generic.c:192
instrument_atomic_write include/linux/instrumented.h:71 [inline]
atomic64_sub_return include/asm-generic/atomic-instrumented.h:970 [inline]
atomic_long_sub_return include/asm-generic/atomic-long.h:113 [inline]
page_counter_cancel mm/page_counter.c:54 [inline]
page_counter_uncharge+0x3d/0xc0 mm/page_counter.c:155
uncharge_batch+0x6c/0x350 mm/memcontrol.c:6764
uncharge_page+0x115/0x430 mm/memcontrol.c:6796
uncharge_list mm/memcontrol.c:6835 [inline]
mem_cgroup_uncharge_list+0x70/0xe0 mm/memcontrol.c:6877
release_pages+0x13a2/0x1550 mm/swap.c:911
tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:242 [inline]
tlb_flush_mmu+0x780/0x910 mm/mmu_gather.c:249
tlb_finish_mmu+0xcb/0x200 mm/mmu_gather.c:328
exit_mmap+0x296/0x550 mm/mmap.c:3185
__mmput+0x113/0x370 kernel/fork.c:1076
exit_mm+0x4cd/0x550 kernel/exit.c:483
do_exit+0x576/0x1f20 kernel/exit.c:793
do_group_exit+0x161/0x2d0 kernel/exit.c:903
get_signal+0x139b/0x1d30 kernel/signal.c:2743
arch_do_signal+0x33/0x610 arch/x86/kernel/signal.c:811
exit_to_user_mode_loop kernel/entry/common.c:135 [inline]
exit_to_user_mode_prepare+0x8d/0x1b0 kernel/entry/common.c:166
syscall_exit_to_user_mode+0x5e/0x1a0 kernel/entry/common.c:241
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Commit 1a3e1f4096 ("mm: memcontrol: decouple reference counting from
page accounting") reworked the memcg lifetime to be bound the the struct
page rather than charges. It also removed the css_put_many from
uncharge_batch and that is causing the above splat.
uncharge_batch() is supposed to uncharge accumulated charges for all
pages freed from the same memcg. The queuing is done by uncharge_page
which however drops the memcg reference after it adds charges to the
batch. If the current page happens to be the last one holding the
reference for its memcg then the memcg is OK to go and the next page to
be freed will trigger batched uncharge which needs to access the memcg
which is gone already.
Fix the issue by taking a reference for the memcg in the current batch.
Fixes: 1a3e1f4096 ("mm: memcontrol: decouple reference counting from page accounting")
Reported-by: syzbot+b305848212deec86eabe@syzkaller.appspotmail.com
Reported-by: syzbot+b5ea6fb6f139c8b9482b@syzkaller.appspotmail.com
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Hugh Dickins <hughd@google.com>
Link: https://lkml.kernel.org/r/20200820090341.GC5033@dhcp22.suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge emailed patches from Peter Xu:
"This is a small series that I picked up from Linus's suggestion to
simplify cow handling (and also make it more strict) by checking
against page refcounts rather than mapcounts.
This makes uffd-wp work again (verified by running upmapsort)"
Note: this is horrendously bad timing, and making this kind of
fundamental vm change after -rc3 is not at all how things should work.
The saving grace is that it really is a a nice simplification:
8 files changed, 29 insertions(+), 120 deletions(-)
The reason for the bad timing is that it turns out that commit
17839856fd ("gup: document and work around 'COW can break either way'
issue" broke not just UFFD functionality (as Peter noticed), but Mikulas
Patocka also reports that it caused issues for strace when running in a
DAX environment with ext4 on a persistent memory setup.
And we can't just revert that commit without re-introducing the original
issue that is a potential security hole, so making COW stricter (and in
the process much simpler) is a step to then undoing the forced COW that
broke other uses.
Link: https://lore.kernel.org/lkml/alpine.LRH.2.02.2009031328040.6929@file01.intranet.prod.int.rdu2.redhat.com/
* emailed patches from Peter Xu <peterx@redhat.com>:
mm: Add PGREUSE counter
mm/gup: Remove enfornced COW mechanism
mm/ksm: Remove reuse_ksm_page()
mm: do_wp_page() simplification
This accounts for wp_page_reuse() case, where we reused a page for COW.
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With the more strict (but greatly simplified) page reuse logic in
do_wp_page(), we can safely go back to the world where cow is not
enforced with writes.
This essentially reverts commit 17839856fd ("gup: document and work
around 'COW can break either way' issue"). There are some context
differences due to some changes later on around it:
2170ecfa76 ("drm/i915: convert get_user_pages() --> pin_user_pages()", 2020-06-03)
376a34efa4 ("mm/gup: refactor and de-duplicate gup_fast() code", 2020-06-03)
Some lines moved back and forth with those, but this revert patch should
have striped out and covered all the enforced cow bits anyways.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove the function as the last reference has gone away with the do_wp_page()
changes.
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
How about we just make sure we're the only possible valid user fo the
page before we bother to reuse it?
Simplify, simplify, simplify.
And get rid of the nasty serialization on the page lock at the same time.
[peterx: add subject prefix]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is in preparation for the logic behind MEMORY_DEVICE_DEVDAX also
being used by non DAX devices.
No functional change intended.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Link: https://lore.kernel.org/r/20200901083326.21264-3-roger.pau@citrix.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Merge gate page refcount fix from Dave Hansen:
"During the conversion over to pin_user_pages(), gate pages were missed.
The fix is pretty simple, and is accompanied by a new test from Andy
which probably would have caught this earlier"
* emailed patches from Dave Hansen <dave.hansen@linux.intel.com>:
selftests/x86/test_vsyscall: Improve the process_vm_readv() test
mm: fix pin vs. gup mismatch with gate pages
Gate pages were missed when converting from get to pin_user_pages().
This can lead to refcount imbalances. This is reliably and quickly
reproducible running the x86 selftests when vsyscall=emulate is enabled
(the default). Fix by using try_grab_page() with appropriate flags
passed.
The long story:
Today, pin_user_pages() and get_user_pages() are similar interfaces for
manipulating page reference counts. However, "pins" use a "bias" value
and manipulate the actual reference count by 1024 instead of 1 used by
plain "gets".
That means that pin_user_pages() must be matched with unpin_user_pages()
and can't be mixed with a plain put_user_pages() or put_page().
Enter gate pages, like the vsyscall page. They are pages usually in the
kernel image, but which are mapped to userspace. Userspace is allowed
access to them, including interfaces using get/pin_user_pages(). The
refcount of these kernel pages is manipulated just like a normal user
page on the get/pin side so that the put/unpin side can work the same
for normal user pages or gate pages.
get_gate_page() uses try_get_page() which only bumps the refcount by
1, not 1024, even if called in the pin_user_pages() path. If someone
pins a gate page, this happens:
pin_user_pages()
get_gate_page()
try_get_page() // bump refcount +1
... some time later
unpin_user_pages()
page_ref_sub_and_test(page, 1024))
... and boom, we get a refcount off by 1023. This is reliably and
quickly reproducible running the x86 selftests when booted with
vsyscall=emulate (the default). The selftests use ptrace(), but I
suspect anything using pin_user_pages() on gate pages could hit this.
To fix it, simply use try_grab_page() instead of try_get_page(), and
pass 'gup_flags' in so that FOLL_PIN can be respected.
This bug traces back to the very beginning of the FOLL_PIN support in
commit 3faa52c03f ("mm/gup: track FOLL_PIN pages"), which showed up in
the 5.7 release.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Fixes: 3faa52c03f ("mm/gup: track FOLL_PIN pages")
Reported-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: x86@kernel.org
Cc: Jann Horn <jannh@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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.
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Merge tag 'powerpc-5.9-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
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"
This reverts commit 5c9fa16e8a.
Since PROT_SAO can still be useful for certain classes of software,
reintroduce it. Concerns about guest migration for LPARs using SAO
will be addressed next.
Signed-off-by: Shawn Anastasio <shawn@anastas.io>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200821185558.35561-2-shawn@anastas.io
The following race is observed with the repeated online, offline and a
delay between two successive online of memory blocks of movable zone.
P1 P2
Online the first memory block in
the movable zone. The pcp struct
values are initialized to default
values,i.e., pcp->high = 0 &
pcp->batch = 1.
Allocate the pages from the
movable zone.
Try to Online the second memory
block in the movable zone thus it
entered the online_pages() but yet
to call zone_pcp_update().
This process is entered into
the exit path thus it tries
to release the order-0 pages
to pcp lists through
free_unref_page_commit().
As pcp->high = 0, pcp->count = 1
proceed to call the function
free_pcppages_bulk().
Update the pcp values thus the
new pcp values are like, say,
pcp->high = 378, pcp->batch = 63.
Read the pcp's batch value using
READ_ONCE() and pass the same to
free_pcppages_bulk(), pcp values
passed here are, batch = 63,
count = 1.
Since num of pages in the pcp
lists are less than ->batch,
then it will stuck in
while(list_empty(list)) loop
with interrupts disabled thus
a core hung.
Avoid this by ensuring free_pcppages_bulk() is called with proper count of
pcp list pages.
The mentioned race is some what easily reproducible without [1] because
pcp's are not updated for the first memory block online and thus there is
a enough race window for P2 between alloc+free and pcp struct values
update through onlining of second memory block.
With [1], the race still exists but it is very narrow as we update the pcp
struct values for the first memory block online itself.
This is not limited to the movable zone, it could also happen in cases
with the normal zone (e.g., hotplug to a node that only has DMA memory, or
no other memory yet).
[1]: https://patchwork.kernel.org/patch/11696389/
Fixes: 5f8dcc2121 ("page-allocator: split per-cpu list into one-list-per-migrate-type")
Signed-off-by: Charan Teja Reddy <charante@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Cc: <stable@vger.kernel.org> [2.6+]
Link: http://lkml.kernel.org/r/1597150703-19003-1-git-send-email-charante@codeaurora.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The lowmem_reserve arrays provide a means of applying pressure against
allocations from lower zones that were targeted at higher zones. Its
values are a function of the number of pages managed by higher zones and
are assigned by a call to the setup_per_zone_lowmem_reserve() function.
The function is initially called at boot time by the function
init_per_zone_wmark_min() and may be called later by accesses of the
/proc/sys/vm/lowmem_reserve_ratio sysctl file.
The function init_per_zone_wmark_min() was moved up from a module_init to
a core_initcall to resolve a sequencing issue with khugepaged.
Unfortunately this created a sequencing issue with CMA page accounting.
The CMA pages are added to the managed page count of a zone when
cma_init_reserved_areas() is called at boot also as a core_initcall. This
makes it uncertain whether the CMA pages will be added to the managed page
counts of their zones before or after the call to
init_per_zone_wmark_min() as it becomes dependent on link order. With the
current link order the pages are added to the managed count after the
lowmem_reserve arrays are initialized at boot.
This means the lowmem_reserve values at boot may be lower than the values
used later if /proc/sys/vm/lowmem_reserve_ratio is accessed even if the
ratio values are unchanged.
In many cases the difference is not significant, but for example
an ARM platform with 1GB of memory and the following memory layout
cma: Reserved 256 MiB at 0x0000000030000000
Zone ranges:
DMA [mem 0x0000000000000000-0x000000002fffffff]
Normal empty
HighMem [mem 0x0000000030000000-0x000000003fffffff]
would result in 0 lowmem_reserve for the DMA zone. This would allow
userspace to deplete the DMA zone easily.
Funnily enough
$ cat /proc/sys/vm/lowmem_reserve_ratio
would fix up the situation because as a side effect it forces
setup_per_zone_lowmem_reserve.
This commit breaks the link order dependency by invoking
init_per_zone_wmark_min() as a postcore_initcall so that the CMA pages
have the chance to be properly accounted in their zone(s) and allowing
the lowmem_reserve arrays to receive consistent values.
Fixes: bc22af74f2 ("mm: update min_free_kbytes from khugepaged after core initialization")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Jason Baron <jbaron@akamai.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/1597423766-27849-1-git-send-email-opendmb@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The compilation with CONFIG_DEBUG_RODATA_TEST set produces the following
warning due to the missing include.
mm/rodata_test.c:15:6: warning: no previous prototype for 'rodata_test' [-Wmissing-prototypes]
15 | void rodata_test(void)
| ^~~~~~~~~~~
Fixes: 2959a5f726 ("mm: add arch-independent testcases for RODATA")
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lkml.kernel.org/r/20200819080026.918134-1-leon@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Like zap_pte_range add cond_resched so that we can avoid softlockups as
reported below. On non-preemptible kernel with large I/O map region (like
the one we get when using persistent memory with sector mode), an unmap of
the namespace can report below softlockups.
22724.027334] watchdog: BUG: soft lockup - CPU#49 stuck for 23s! [ndctl:50777]
NIP [c0000000000dc224] plpar_hcall+0x38/0x58
LR [c0000000000d8898] pSeries_lpar_hpte_invalidate+0x68/0xb0
Call Trace:
flush_hash_page+0x114/0x200
hpte_need_flush+0x2dc/0x540
vunmap_page_range+0x538/0x6f0
free_unmap_vmap_area+0x30/0x70
remove_vm_area+0xfc/0x140
__vunmap+0x68/0x270
__iounmap.part.0+0x34/0x60
memunmap+0x54/0x70
release_nodes+0x28c/0x300
device_release_driver_internal+0x16c/0x280
unbind_store+0x124/0x170
drv_attr_store+0x44/0x60
sysfs_kf_write+0x64/0x90
kernfs_fop_write+0x1b0/0x290
__vfs_write+0x3c/0x70
vfs_write+0xd8/0x260
ksys_write+0xdc/0x130
system_call+0x5c/0x70
Reported-by: Harish Sriram <harish@linux.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200807075933.310240-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
syzbot crashes on the VM_BUG_ON_MM(khugepaged_test_exit(mm), mm) in
__khugepaged_enter(): yes, when one thread is about to dump core, has set
core_state, and is waiting for others, another might do something calling
__khugepaged_enter(), which now crashes because I lumped the core_state
test (known as "mmget_still_valid") into khugepaged_test_exit(). I still
think it's best to lump them together, so just in this exceptional case,
check mm->mm_users directly instead of khugepaged_test_exit().
Fixes: bbe98f9cad ("khugepaged: khugepaged_test_exit() check mmget_still_valid()")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Yang Shi <shy828301@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: <stable@vger.kernel.org> [4.8+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008141503370.18085@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace a comma between expression statements by a semicolon.
Fixes: faced7e080 ("mm: hugetlb controller for cgroups v2")
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Giuseppe Scrivano <gscrivan@redhat.com>
Link: http://lkml.kernel.org/r/20200818064333.21759-1-vulab@iscas.ac.cn
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Recently we found regression when running will_it_scale/page_fault3 test
on ARM64. Over 70% down for the multi processes cases and over 20% down
for the multi threads cases. It turns out the regression is caused by
commit 89b15332af ("mm: drop mmap_sem before calling
balance_dirty_pages() in write fault").
The test mmaps a memory size file then write to the mapping, this would
make all memory dirty and trigger dirty pages throttle, that upstream
commit would release mmap_sem then retry the page fault. The retried
page fault would see correct PTEs installed then just fall through to
spurious TLB flush. The regression is caused by the excessive spurious
TLB flush. It is fine on x86 since x86's spurious TLB flush is no-op.
We could just skip the spurious TLB flush to mitigate the regression.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Xu Yu <xuyu@linux.alibaba.com>
Debugged-by: Xu Yu <xuyu@linux.alibaba.com>
Tested-by: Xu Yu <xuyu@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Yang Shi <shy828301@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge more updates from Andrew Morton:
"Subsystems affected by this patch series: mm/hotfixes, lz4, exec,
mailmap, mm/thp, autofs, sysctl, mm/kmemleak, mm/misc and lib"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (35 commits)
virtio: pci: constify ioreadX() iomem argument (as in generic implementation)
ntb: intel: constify ioreadX() iomem argument (as in generic implementation)
rtl818x: constify ioreadX() iomem argument (as in generic implementation)
iomap: constify ioreadX() iomem argument (as in generic implementation)
sh: use generic strncpy()
sh: clkfwk: remove r8/r16/r32
include/asm-generic/vmlinux.lds.h: align ro_after_init
mm: annotate a data race in page_zonenum()
mm/swap.c: annotate data races for lru_rotate_pvecs
mm/rmap: annotate a data race at tlb_flush_batched
mm/mempool: fix a data race in mempool_free()
mm/list_lru: fix a data race in list_lru_count_one
mm/memcontrol: fix a data race in scan count
mm/page_counter: fix various data races at memsw
mm/swapfile: fix and annotate various data races
mm/filemap.c: fix a data race in filemap_fault()
mm/swap_state: mark various intentional data races
mm/page_io: mark various intentional data races
mm/frontswap: mark various intentional data races
mm/kmemleak: silence KCSAN splats in checksum
...
Read to lru_add_pvec->nr could be interrupted and then write to the same
variable. The write has local interrupt disabled, but the plain reads
result in data races. However, it is unlikely the compilers could do much
damage here given that lru_add_pvec->nr is a "unsigned char" and there is
an existing compiler barrier. Thus, annotate the reads using the
data_race() macro. The data races were reported by KCSAN,
BUG: KCSAN: data-race in lru_add_drain_cpu / rotate_reclaimable_page
write to 0xffff9291ebcb8a40 of 1 bytes by interrupt on cpu 23:
rotate_reclaimable_page+0x2df/0x490
pagevec_add at include/linux/pagevec.h:81
(inlined by) rotate_reclaimable_page at mm/swap.c:259
end_page_writeback+0x1b5/0x2b0
end_swap_bio_write+0x1d0/0x280
bio_endio+0x297/0x560
dec_pending+0x218/0x430 [dm_mod]
clone_endio+0xe4/0x2c0 [dm_mod]
bio_endio+0x297/0x560
blk_update_request+0x201/0x920
scsi_end_request+0x6b/0x4a0
scsi_io_completion+0xb7/0x7e0
scsi_finish_command+0x1ed/0x2a0
scsi_softirq_done+0x1c9/0x1d0
blk_done_softirq+0x181/0x1d0
__do_softirq+0xd9/0x57c
irq_exit+0xa2/0xc0
do_IRQ+0x8b/0x190
ret_from_intr+0x0/0x42
delay_tsc+0x46/0x80
__const_udelay+0x3c/0x40
__udelay+0x10/0x20
kcsan_setup_watchpoint+0x202/0x3a0
__tsan_read1+0xc2/0x100
lru_add_drain_cpu+0xb8/0x3f0
lru_add_drain+0x25/0x40
shrink_active_list+0xe1/0xc80
shrink_lruvec+0x766/0xb70
shrink_node+0x2d6/0xca0
do_try_to_free_pages+0x1f7/0x9a0
try_to_free_pages+0x252/0x5b0
__alloc_pages_slowpath+0x458/0x1290
__alloc_pages_nodemask+0x3bb/0x450
alloc_pages_vma+0x8a/0x2c0
do_anonymous_page+0x16e/0x6f0
__handle_mm_fault+0xcd5/0xd40
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40
read to 0xffff9291ebcb8a40 of 1 bytes by task 37761 on cpu 23:
lru_add_drain_cpu+0xb8/0x3f0
lru_add_drain_cpu at mm/swap.c:602
lru_add_drain+0x25/0x40
shrink_active_list+0xe1/0xc80
shrink_lruvec+0x766/0xb70
shrink_node+0x2d6/0xca0
do_try_to_free_pages+0x1f7/0x9a0
try_to_free_pages+0x252/0x5b0
__alloc_pages_slowpath+0x458/0x1290
__alloc_pages_nodemask+0x3bb/0x450
alloc_pages_vma+0x8a/0x2c0
do_anonymous_page+0x16e/0x6f0
__handle_mm_fault+0xcd5/0xd40
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40
2 locks held by oom02/37761:
#0: ffff9281e5928808 (&mm->mmap_sem#2){++++}, at: do_page_fault
#1: ffffffffb3ade380 (fs_reclaim){+.+.}, at: fs_reclaim_acquire.part
irq event stamp: 1949217
trace_hardirqs_on_thunk+0x1a/0x1c
__do_softirq+0x2e7/0x57c
__do_softirq+0x34c/0x57c
irq_exit+0xa2/0xc0
Reported by Kernel Concurrency Sanitizer on:
CPU: 23 PID: 37761 Comm: oom02 Not tainted 5.6.0-rc3-next-20200226+ #6
Hardware name: HP ProLiant BL660c Gen9, BIOS I38 10/17/2018
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Marco Elver <elver@google.com>
Link: http://lkml.kernel.org/r/20200228044018.1263-1-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm->tlb_flush_batched could be accessed concurrently as noticed by
KCSAN,
BUG: KCSAN: data-race in flush_tlb_batched_pending / try_to_unmap_one
write to 0xffff93f754880bd0 of 1 bytes by task 822 on cpu 6:
try_to_unmap_one+0x59a/0x1ab0
set_tlb_ubc_flush_pending at mm/rmap.c:635
(inlined by) try_to_unmap_one at mm/rmap.c:1538
rmap_walk_anon+0x296/0x650
rmap_walk+0xdf/0x100
try_to_unmap+0x18a/0x2f0
shrink_page_list+0xef6/0x2870
shrink_inactive_list+0x316/0x880
shrink_lruvec+0x8dc/0x1380
shrink_node+0x317/0xd80
balance_pgdat+0x652/0xd90
kswapd+0x396/0x8d0
kthread+0x1e0/0x200
ret_from_fork+0x27/0x50
read to 0xffff93f754880bd0 of 1 bytes by task 6364 on cpu 4:
flush_tlb_batched_pending+0x29/0x90
flush_tlb_batched_pending at mm/rmap.c:682
change_p4d_range+0x5dd/0x1030
change_pte_range at mm/mprotect.c:44
(inlined by) change_pmd_range at mm/mprotect.c:212
(inlined by) change_pud_range at mm/mprotect.c:240
(inlined by) change_p4d_range at mm/mprotect.c:260
change_protection+0x222/0x310
change_prot_numa+0x3e/0x60
task_numa_work+0x219/0x350
task_work_run+0xed/0x140
prepare_exit_to_usermode+0x2cc/0x2e0
ret_from_intr+0x32/0x42
Reported by Kernel Concurrency Sanitizer on:
CPU: 4 PID: 6364 Comm: mtest01 Tainted: G W L 5.5.0-next-20200210+ #5
Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019
flush_tlb_batched_pending() is under PTL but the write is not, but
mm->tlb_flush_batched is only a bool type, so the value is unlikely to be
shattered. Thus, mark it as an intentional data race by using the data
race macro.
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Marco Elver <elver@google.com>
Link: http://lkml.kernel.org/r/1581450783-8262-1-git-send-email-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mempool_t pool.curr_nr could be accessed concurrently as noticed by
KCSAN,
BUG: KCSAN: data-race in mempool_free / remove_element
write to 0xffffffffa937638c of 4 bytes by task 6359 on cpu 113:
remove_element+0x4a/0x1c0
remove_element at mm/mempool.c:132
mempool_alloc+0x102/0x210
(inlined by) mempool_alloc at mm/mempool.c:399
bio_alloc_bioset+0x106/0x2c0
get_swap_bio+0x49/0x230
__swap_writepage+0x680/0xc30
swap_writepage+0x9c/0xf0
pageout+0x33e/0xae0
shrink_page_list+0x1f57/0x2870
shrink_inactive_list+0x316/0x880
shrink_lruvec+0x8dc/0x1380
shrink_node+0x317/0xd80
do_try_to_free_pages+0x1f7/0xa10
try_to_free_pages+0x26c/0x5e0
__alloc_pages_slowpath+0x458/0x1290
<snip>
read to 0xffffffffa937638c of 4 bytes by interrupt on cpu 64:
mempool_free+0x3e/0x150
mempool_free at mm/mempool.c:492
bio_free+0x192/0x280
bio_put+0x91/0xd0
end_swap_bio_write+0x1d8/0x280
bio_endio+0x2c2/0x5b0
dec_pending+0x22b/0x440 [dm_mod]
clone_endio+0xe4/0x2c0 [dm_mod]
bio_endio+0x2c2/0x5b0
blk_update_request+0x217/0x940
scsi_end_request+0x6b/0x4d0
scsi_io_completion+0xb7/0x7e0
scsi_finish_command+0x223/0x310
scsi_softirq_done+0x1d5/0x210
blk_mq_complete_request+0x224/0x250
scsi_mq_done+0xc2/0x250
pqi_raid_io_complete+0x5a/0x70 [smartpqi]
pqi_irq_handler+0x150/0x1410 [smartpqi]
__handle_irq_event_percpu+0x90/0x540
handle_irq_event_percpu+0x49/0xd0
handle_irq_event+0x85/0xca
handle_edge_irq+0x13f/0x3e0
do_IRQ+0x86/0x190
<snip>
Since the write is under pool->lock but the read is done as lockless.
Even though the commit 5b990546e3 ("mempool: fix and document
synchronization and memory barrier usage") introduced the smp_wmb() and
smp_rmb() pair to improve the situation, it is adequate to protect it
from data races which could lead to a logic bug, so fix it by adding
READ_ONCE() for the read.
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Marco Elver <elver@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Link: http://lkml.kernel.org/r/1581446384-2131-1-git-send-email-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
struct list_lru_one l.nr_items could be accessed concurrently as noticed
by KCSAN,
BUG: KCSAN: data-race in list_lru_count_one / list_lru_isolate_move
write to 0xffffa102789c4510 of 8 bytes by task 823 on cpu 39:
list_lru_isolate_move+0xf9/0x130
list_lru_isolate_move at mm/list_lru.c:180
inode_lru_isolate+0x12b/0x2a0
__list_lru_walk_one+0x122/0x3d0
list_lru_walk_one+0x75/0xa0
prune_icache_sb+0x8b/0xc0
super_cache_scan+0x1b8/0x250
do_shrink_slab+0x256/0x6d0
shrink_slab+0x41b/0x4a0
shrink_node+0x35c/0xd80
balance_pgdat+0x652/0xd90
kswapd+0x396/0x8d0
kthread+0x1e0/0x200
ret_from_fork+0x27/0x50
read to 0xffffa102789c4510 of 8 bytes by task 6345 on cpu 56:
list_lru_count_one+0x116/0x2f0
list_lru_count_one at mm/list_lru.c:193
super_cache_count+0xe8/0x170
do_shrink_slab+0x95/0x6d0
shrink_slab+0x41b/0x4a0
shrink_node+0x35c/0xd80
do_try_to_free_pages+0x1f7/0xa10
try_to_free_pages+0x26c/0x5e0
__alloc_pages_slowpath+0x458/0x1290
__alloc_pages_nodemask+0x3bb/0x450
alloc_pages_vma+0x8a/0x2c0
do_anonymous_page+0x170/0x700
__handle_mm_fault+0xc9f/0xd00
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40
Reported by Kernel Concurrency Sanitizer on:
CPU: 56 PID: 6345 Comm: oom01 Tainted: G W L 5.5.0-next-20200205+ #4
Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019
A shattered l.nr_items could affect the shrinker behaviour due to a data
race. Fix it by adding READ_ONCE() for the read. Since the writes are
aligned and up to word-size, assume those are safe from data races to
avoid readability issues of writing WRITE_ONCE(var, var + val).
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Marco Elver <elver@google.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Link: http://lkml.kernel.org/r/1581114679-5488-1-git-send-email-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 3e32cb2e0a ("mm: memcontrol: lockless page counters") could had
memcg->memsw->watermark and memcg->memsw->failcnt been accessed
concurrently as reported by KCSAN,
BUG: KCSAN: data-race in page_counter_try_charge / page_counter_try_charge
read to 0xffff8fb18c4cd190 of 8 bytes by task 1081 on cpu 59:
page_counter_try_charge+0x4d/0x150 mm/page_counter.c:138
try_charge+0x131/0xd50 mm/memcontrol.c:2405
__memcg_kmem_charge_memcg+0x58/0x140
__memcg_kmem_charge+0xcc/0x280
__alloc_pages_nodemask+0x1e1/0x450
alloc_pages_current+0xa6/0x120
pte_alloc_one+0x17/0xd0
__pte_alloc+0x3a/0x1f0
copy_p4d_range+0xc36/0x1990
copy_page_range+0x21d/0x360
dup_mmap+0x5f5/0x7a0
dup_mm+0xa2/0x240
copy_process+0x1b3f/0x3460
_do_fork+0xaa/0xa20
__x64_sys_clone+0x13b/0x170
do_syscall_64+0x91/0xb47
entry_SYSCALL_64_after_hwframe+0x49/0xbe
write to 0xffff8fb18c4cd190 of 8 bytes by task 1153 on cpu 120:
page_counter_try_charge+0x5b/0x150 mm/page_counter.c:139
try_charge+0x131/0xd50 mm/memcontrol.c:2405
mem_cgroup_try_charge+0x159/0x460
mem_cgroup_try_charge_delay+0x3d/0xa0
wp_page_copy+0x14d/0x930
do_wp_page+0x107/0x7b0
__handle_mm_fault+0xce6/0xd40
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40
BUG: KCSAN: data-race in page_counter_try_charge / page_counter_try_charge
write to 0xffff88809bbf2158 of 8 bytes by task 11782 on cpu 0:
page_counter_try_charge+0x100/0x170 mm/page_counter.c:129
try_charge+0x185/0xbf0 mm/memcontrol.c:2405
__memcg_kmem_charge_memcg+0x4a/0xe0 mm/memcontrol.c:2837
__memcg_kmem_charge+0xcf/0x1b0 mm/memcontrol.c:2877
__alloc_pages_nodemask+0x26c/0x310 mm/page_alloc.c:4780
read to 0xffff88809bbf2158 of 8 bytes by task 11814 on cpu 1:
page_counter_try_charge+0xef/0x170 mm/page_counter.c:129
try_charge+0x185/0xbf0 mm/memcontrol.c:2405
__memcg_kmem_charge_memcg+0x4a/0xe0 mm/memcontrol.c:2837
__memcg_kmem_charge+0xcf/0x1b0 mm/memcontrol.c:2877
__alloc_pages_nodemask+0x26c/0x310 mm/page_alloc.c:4780
Since watermark could be compared or set to garbage due to a data race
which would change the code logic, fix it by adding a pair of READ_ONCE()
and WRITE_ONCE() in those places.
The "failcnt" counter is tolerant of some degree of inaccuracy and is only
used to report stats, a data race will not be harmful, thus mark it as an
intentional data race using the data_race() macro.
Fixes: 3e32cb2e0a ("mm: memcontrol: lockless page counters")
Reported-by: syzbot+f36cfe60b1006a94f9dc@syzkaller.appspotmail.com
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Link: http://lkml.kernel.org/r/1581519682-23594-1-git-send-email-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
swap_info_struct si.highest_bit, si.swap_map[offset] and si.flags could
be accessed concurrently separately as noticed by KCSAN,
=== si.highest_bit ===
write to 0xffff8d5abccdc4d4 of 4 bytes by task 5353 on cpu 24:
swap_range_alloc+0x81/0x130
swap_range_alloc at mm/swapfile.c:681
scan_swap_map_slots+0x371/0xb90
get_swap_pages+0x39d/0x5c0
get_swap_page+0xf2/0x524
add_to_swap+0xe4/0x1c0
shrink_page_list+0x1795/0x2870
shrink_inactive_list+0x316/0x880
shrink_lruvec+0x8dc/0x1380
shrink_node+0x317/0xd80
do_try_to_free_pages+0x1f7/0xa10
try_to_free_pages+0x26c/0x5e0
__alloc_pages_slowpath+0x458/0x1290
read to 0xffff8d5abccdc4d4 of 4 bytes by task 6672 on cpu 70:
scan_swap_map_slots+0x4a6/0xb90
scan_swap_map_slots at mm/swapfile.c:892
get_swap_pages+0x39d/0x5c0
get_swap_page+0xf2/0x524
add_to_swap+0xe4/0x1c0
shrink_page_list+0x1795/0x2870
shrink_inactive_list+0x316/0x880
shrink_lruvec+0x8dc/0x1380
shrink_node+0x317/0xd80
do_try_to_free_pages+0x1f7/0xa10
try_to_free_pages+0x26c/0x5e0
__alloc_pages_slowpath+0x458/0x1290
Reported by Kernel Concurrency Sanitizer on:
CPU: 70 PID: 6672 Comm: oom01 Tainted: G W L 5.5.0-next-20200205+ #3
Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019
=== si.swap_map[offset] ===
write to 0xffffbc370c29a64c of 1 bytes by task 6856 on cpu 86:
__swap_entry_free_locked+0x8c/0x100
__swap_entry_free_locked at mm/swapfile.c:1209 (discriminator 4)
__swap_entry_free.constprop.20+0x69/0xb0
free_swap_and_cache+0x53/0xa0
unmap_page_range+0x7f8/0x1d70
unmap_single_vma+0xcd/0x170
unmap_vmas+0x18b/0x220
exit_mmap+0xee/0x220
mmput+0x10e/0x270
do_exit+0x59b/0xf40
do_group_exit+0x8b/0x180
read to 0xffffbc370c29a64c of 1 bytes by task 6855 on cpu 20:
_swap_info_get+0x81/0xa0
_swap_info_get at mm/swapfile.c:1140
free_swap_and_cache+0x40/0xa0
unmap_page_range+0x7f8/0x1d70
unmap_single_vma+0xcd/0x170
unmap_vmas+0x18b/0x220
exit_mmap+0xee/0x220
mmput+0x10e/0x270
do_exit+0x59b/0xf40
do_group_exit+0x8b/0x180
=== si.flags ===
write to 0xffff956c8fc6c400 of 8 bytes by task 6087 on cpu 23:
scan_swap_map_slots+0x6fe/0xb50
scan_swap_map_slots at mm/swapfile.c:887
get_swap_pages+0x39d/0x5c0
get_swap_page+0x377/0x524
add_to_swap+0xe4/0x1c0
shrink_page_list+0x1795/0x2870
shrink_inactive_list+0x316/0x880
shrink_lruvec+0x8dc/0x1380
shrink_node+0x317/0xd80
do_try_to_free_pages+0x1f7/0xa10
try_to_free_pages+0x26c/0x5e0
__alloc_pages_slowpath+0x458/0x1290
read to 0xffff956c8fc6c400 of 8 bytes by task 6207 on cpu 63:
_swap_info_get+0x41/0xa0
__swap_info_get at mm/swapfile.c:1114
put_swap_page+0x84/0x490
__remove_mapping+0x384/0x5f0
shrink_page_list+0xff1/0x2870
shrink_inactive_list+0x316/0x880
shrink_lruvec+0x8dc/0x1380
shrink_node+0x317/0xd80
do_try_to_free_pages+0x1f7/0xa10
try_to_free_pages+0x26c/0x5e0
__alloc_pages_slowpath+0x458/0x1290
The writes are under si->lock but the reads are not. For si.highest_bit
and si.swap_map[offset], data race could trigger logic bugs, so fix them
by having WRITE_ONCE() for the writes and READ_ONCE() for the reads
except those isolated reads where they compare against zero which a data
race would cause no harm. Thus, annotate them as intentional data races
using the data_race() macro.
For si.flags, the readers are only interested in a single bit where a
data race there would cause no issue there.
[cai@lca.pw: add a missing annotation for si->flags in memory.c]
Link: http://lkml.kernel.org/r/1581612647-5958-1-git-send-email-cai@lca.pw
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Marco Elver <elver@google.com>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/1581095163-12198-1-git-send-email-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
struct file_ra_state ra.mmap_miss could be accessed concurrently during
page faults as noticed by KCSAN,
BUG: KCSAN: data-race in filemap_fault / filemap_map_pages
write to 0xffff9b1700a2c1b4 of 4 bytes by task 3292 on cpu 30:
filemap_fault+0x920/0xfc0
do_sync_mmap_readahead at mm/filemap.c:2384
(inlined by) filemap_fault at mm/filemap.c:2486
__xfs_filemap_fault+0x112/0x3e0 [xfs]
xfs_filemap_fault+0x74/0x90 [xfs]
__do_fault+0x9e/0x220
do_fault+0x4a0/0x920
__handle_mm_fault+0xc69/0xd00
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40
read to 0xffff9b1700a2c1b4 of 4 bytes by task 3313 on cpu 32:
filemap_map_pages+0xc2e/0xd80
filemap_map_pages at mm/filemap.c:2625
do_fault+0x3da/0x920
__handle_mm_fault+0xc69/0xd00
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40
Reported by Kernel Concurrency Sanitizer on:
CPU: 32 PID: 3313 Comm: systemd-udevd Tainted: G W L 5.5.0-next-20200210+ #1
Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019
ra.mmap_miss is used to contribute the readahead decisions, a data race
could be undesirable. Both the read and write is only under non-exclusive
mmap_sem, two concurrent writers could even underflow the counter. Fix
the underflow by writing to a local variable before committing a final
store to ra.mmap_miss given a small inaccuracy of the counter should be
acceptable.
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Qian Cai <cai@lca.pw>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Marco Elver <elver@google.com>
Link: http://lkml.kernel.org/r/20200211030134.1847-1-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
swap_cache_info.* could be accessed concurrently as noticed by
KCSAN,
BUG: KCSAN: data-race in lookup_swap_cache / lookup_swap_cache
write to 0xffffffff85517318 of 8 bytes by task 94138 on cpu 101:
lookup_swap_cache+0x12e/0x460
lookup_swap_cache at mm/swap_state.c:322
do_swap_page+0x112/0xeb0
__handle_mm_fault+0xc7a/0xd00
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40
read to 0xffffffff85517318 of 8 bytes by task 91655 on cpu 100:
lookup_swap_cache+0x117/0x460
lookup_swap_cache at mm/swap_state.c:322
shmem_swapin_page+0xc7/0x9e0
shmem_getpage_gfp+0x2ca/0x16c0
shmem_fault+0xef/0x3c0
__do_fault+0x9e/0x220
do_fault+0x4a0/0x920
__handle_mm_fault+0xc69/0xd00
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40
Reported by Kernel Concurrency Sanitizer on:
CPU: 100 PID: 91655 Comm: systemd-journal 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
write to 0xffffffff8d717308 of 8 bytes by task 11365 on cpu 87:
__delete_from_swap_cache+0x681/0x8b0
__delete_from_swap_cache at mm/swap_state.c:178
read to 0xffffffff8d717308 of 8 bytes by task 11275 on cpu 53:
__delete_from_swap_cache+0x66e/0x8b0
__delete_from_swap_cache at mm/swap_state.c:178
Both the read and write are done as lockless. Since swap_cache_info.*
are only used to print out counter information, even if any of them
missed a few incremental due to data races, it will be harmless, so just
mark it as an intentional data race using the data_race() macro.
While at it, fix a checkpatch.pl warning,
WARNING: Single statement macros should not use a do {} while (0) loop
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Marco Elver <elver@google.com>
Link: http://lkml.kernel.org/r/20200207003715.1578-1-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
struct swap_info_struct si.flags could be accessed concurrently as noticed
by KCSAN,
BUG: KCSAN: data-race in scan_swap_map_slots / swap_readpage
write to 0xffff9c77b80ac400 of 8 bytes by task 91325 on cpu 16:
scan_swap_map_slots+0x6fe/0xb50
scan_swap_map_slots at mm/swapfile.c:887
get_swap_pages+0x39d/0x5c0
get_swap_page+0x377/0x524
add_to_swap+0xe4/0x1c0
shrink_page_list+0x1740/0x2820
shrink_inactive_list+0x316/0x8b0
shrink_lruvec+0x8dc/0x1380
shrink_node+0x317/0xd80
do_try_to_free_pages+0x1f7/0xa10
try_to_free_pages+0x26c/0x5e0
__alloc_pages_slowpath+0x458/0x1290
__alloc_pages_nodemask+0x3bb/0x450
alloc_pages_vma+0x8a/0x2c0
do_anonymous_page+0x170/0x700
__handle_mm_fault+0xc9f/0xd00
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40
read to 0xffff9c77b80ac400 of 8 bytes by task 5422 on cpu 7:
swap_readpage+0x204/0x6a0
swap_readpage at mm/page_io.c:380
read_swap_cache_async+0xa2/0xb0
swapin_readahead+0x6a0/0x890
do_swap_page+0x465/0xeb0
__handle_mm_fault+0xc7a/0xd00
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40
Reported by Kernel Concurrency Sanitizer on:
CPU: 7 PID: 5422 Comm: gmain 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
Other reads,
read to 0xffff91ea33eac400 of 8 bytes by task 11276 on cpu 120:
__swap_writepage+0x140/0xc20
__swap_writepage at mm/page_io.c:289
read to 0xffff91ea33eac400 of 8 bytes by task 11264 on cpu 16:
swap_set_page_dirty+0x44/0x1f4
swap_set_page_dirty at mm/page_io.c:442
The write is under &si->lock, but the reads are done as lockless. Since
the reads only check for a specific bit in the flag, it is harmless even
if load tearing happens. Thus, just mark them as intentional data races
using the data_race() macro.
[cai@lca.pw: add a missing annotation]
Link: http://lkml.kernel.org/r/1581612585-5812-1-git-send-email-cai@lca.pw
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Marco Elver <elver@google.com>
Link: http://lkml.kernel.org/r/20200207003601.1526-1-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are a few information counters that are intentionally not protected
against increment races, so just annotate them using the data_race()
macro.
BUG: KCSAN: data-race in __frontswap_store / __frontswap_store
write to 0xffffffff8b7174d8 of 8 bytes by task 6396 on cpu 103:
__frontswap_store+0x2d0/0x344
inc_frontswap_failed_stores at mm/frontswap.c:70
(inlined by) __frontswap_store at mm/frontswap.c:280
swap_writepage+0x83/0xf0
pageout+0x33e/0xae0
shrink_page_list+0x1f57/0x2870
shrink_inactive_list+0x316/0x880
shrink_lruvec+0x8dc/0x1380
shrink_node+0x317/0xd80
do_try_to_free_pages+0x1f7/0xa10
try_to_free_pages+0x26c/0x5e0
__alloc_pages_slowpath+0x458/0x1290
__alloc_pages_nodemask+0x3bb/0x450
alloc_pages_vma+0x8a/0x2c0
do_anonymous_page+0x170/0x700
__handle_mm_fault+0xc9f/0xd00
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40
read to 0xffffffff8b7174d8 of 8 bytes by task 6405 on cpu 47:
__frontswap_store+0x2b9/0x344
inc_frontswap_failed_stores at mm/frontswap.c:70
(inlined by) __frontswap_store at mm/frontswap.c:280
swap_writepage+0x83/0xf0
pageout+0x33e/0xae0
shrink_page_list+0x1f57/0x2870
shrink_inactive_list+0x316/0x880
shrink_lruvec+0x8dc/0x1380
shrink_node+0x317/0xd80
do_try_to_free_pages+0x1f7/0xa10
try_to_free_pages+0x26c/0x5e0
__alloc_pages_slowpath+0x458/0x1290
__alloc_pages_nodemask+0x3bb/0x450
alloc_pages_vma+0x8a/0x2c0
do_anonymous_page+0x170/0x700
__handle_mm_fault+0xc9f/0xd00
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Marco Elver <elver@google.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Link: http://lkml.kernel.org/r/1581114499-5042-1-git-send-email-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Even if KCSAN is disabled for kmemleak, update_checksum() could still call
crc32() (which is outside of kmemleak.c) to dereference object->pointer.
Thus, the value of object->pointer could be accessed concurrently as
noticed by KCSAN,
BUG: KCSAN: data-race in crc32_le_base / do_raw_spin_lock
write to 0xffffb0ea683a7d50 of 4 bytes by task 23575 on cpu 12:
do_raw_spin_lock+0x114/0x200
debug_spin_lock_after at kernel/locking/spinlock_debug.c:91
(inlined by) do_raw_spin_lock at kernel/locking/spinlock_debug.c:115
_raw_spin_lock+0x40/0x50
__handle_mm_fault+0xa9e/0xd00
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40
read to 0xffffb0ea683a7d50 of 4 bytes by task 839 on cpu 60:
crc32_le_base+0x67/0x350
crc32_le_base+0x67/0x350:
crc32_body at lib/crc32.c:106
(inlined by) crc32_le_generic at lib/crc32.c:179
(inlined by) crc32_le at lib/crc32.c:197
kmemleak_scan+0x528/0xd90
update_checksum at mm/kmemleak.c:1172
(inlined by) kmemleak_scan at mm/kmemleak.c:1497
kmemleak_scan_thread+0xcc/0xfa
kthread+0x1e0/0x200
ret_from_fork+0x27/0x50
If a shattered value was returned due to a data race, it will be corrected
in the next scan. Thus, let KCSAN ignore all reads in the region to
silence KCSAN in case the write side is non-atomic.
Suggested-by: Marco Elver <elver@google.com>
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Marco Elver <elver@google.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: http://lkml.kernel.org/r/20200317182754.2180-1-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The thp prefix is more frequently used than hpage and we should be
consistent between the various functions.
[akpm@linux-foundation.org: fix mm/migrate.c]
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Link: http://lkml.kernel.org/r/20200629151959.15779-6-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This function returns the number of bytes in a THP. It is like
page_size(), but compiles to just PAGE_SIZE if CONFIG_TRANSPARENT_HUGEPAGE
is disabled.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Link: http://lkml.kernel.org/r/20200629151959.15779-5-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "THP prep patches".
These are some generic cleanups and improvements, which I would like
merged into mmotm soon. The first one should be a performance improvement
for all users of compound pages, and the others are aimed at getting code
to compile away when CONFIG_TRANSPARENT_HUGEPAGE is disabled (ie small
systems). Also better documented / less confusing than the current prefix
mixture of compound, hpage and thp.
This patch (of 7):
This removes a few instructions from functions which need to know how many
pages are in a compound page. The storage used is either page->mapping on
64-bit or page->index on 32-bit. Both of these are fine to overlay on
tail pages.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Link: http://lkml.kernel.org/r/20200629151959.15779-1-willy@infradead.org
Link: http://lkml.kernel.org/r/20200629151959.15779-2-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit 26e7deadaa.
Sonny reported that one of their tests started failing on the latest
kernel on their Chrome OS platform. The root cause is that the above
commit removed the protection line of empty zone, while the parser used in
the test relies on the protection line to mark the end of each zone.
Let's revert it to avoid breaking userspace testing or applications.
Fixes: 26e7deadaa ("mm/vmstat.c: do not show lowmem reserve protection information of empty zone)"
Reported-by: Sonny Rao <sonnyrao@chromium.org>
Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org> [5.8.x]
Link: http://lkml.kernel.org/r/20200811075412.12872-1-bhe@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This remoes the code from the COW path to call debug_dma_assert_idle(),
which was added many years ago.
Google shows that it hasn't caught anything in the 6+ years we've had it
apart from a false positive, and Hugh just noticed how it had a very
unfortunate spinlock serialization in the COW path.
He fixed that issue the previous commit (a85ffd59bd36: "dma-debug: fix
debug_dma_assert_idle(), use rcu_read_lock()"), but let's see if anybody
even notices when we remove this function entirely.
NOTE! We keep the dma tracking infrastructure that was added by the
commit that introduced it. Partly to make it easier to resurrect this
debug code if we ever deside to, and partly because that tracking by pfn
and offset looks quite reasonable.
The problem with this debug code was simply that it was expensive and
didn't seem worth it, not that it was wrong per se.
Acked-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 3e38e0aaca ("mm: memcg: charge memcg percpu memory to the
parent cgroup") adds memory tracking to the memcg kernel structures
themselves to make cgroups liable for the memory they are consuming
through the allocation of child groups (which can be significant).
This code is a bit awkward as it's spread out through several functions:
The outermost function does memalloc_use_memcg(parent) to set up
current->active_memcg, which designates which cgroup to charge, and the
inner functions pass GFP_ACCOUNT to request charging for specific
allocations. To make sure this dependency is satisfied at all times -
to make sure we don't randomly charge whoever is calling the functions -
the inner functions warn on !current->active_memcg.
However, this triggers a false warning when the root memcg itself is
allocated. No parent exists in this case, and so current->active_memcg
is rightfully NULL. It's a false positive, not indicative of a bug.
Delete the warnings for now, we can revisit this later.
Fixes: 3e38e0aaca ("mm: memcg: charge memcg percpu memory to the parent cgroup")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After the cleanup of page fault accounting, gup does not need to pass
task_struct around any more. Remove that parameter in the whole gup
stack.
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Link: http://lkml.kernel.org/r/20200707225021.200906-26-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus Torvalds