b51d5fed9f53e07ce9fc65efb4ff1abe021a4c16
15777 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
NARIBAYASHI Akira
|
882734bbc5 |
mm, compaction: fix fast_isolate_around() to stay within boundaries
commit be21b32afe470c5ae98e27e49201158a47032942 upstream.
Depending on the memory configuration, isolate_freepages_block() may scan
pages out of the target range and causes panic.
Panic can occur on systems with multiple zones in a single pageblock.
The reason it is rare is that it only happens in special
configurations. Depending on how many similar systems there are, it
may be a good idea to fix this problem for older kernels as well.
The problem is that pfn as argument of fast_isolate_around() could be out
of the target range. Therefore we should consider the case where pfn <
start_pfn, and also the case where end_pfn < pfn.
This problem should have been addressd by the commit 6e2b7044c199 ("mm,
compaction: make fast_isolate_freepages() stay within zone") but there was
an oversight.
Case1: pfn < start_pfn
<at memory compaction for node Y>
| node X's zone | node Y's zone
+-----------------+------------------------------...
pageblock ^ ^ ^
+-----------+-----------+-----------+-----------+...
^ ^ ^
^ ^ end_pfn
^ start_pfn = cc->zone->zone_start_pfn
pfn
<---------> scanned range by "Scan After"
Case2: end_pfn < pfn
<at memory compaction for node X>
| node X's zone | node Y's zone
+-----------------+------------------------------...
pageblock ^ ^ ^
+-----------+-----------+-----------+-----------+...
^ ^ ^
^ ^ pfn
^ end_pfn
start_pfn
<---------> scanned range by "Scan Before"
It seems that there is no good reason to skip nr_isolated pages just after
given pfn. So let perform simple scan from start to end instead of
dividing the scan into "Before" and "After".
Link: https://lkml.kernel.org/r/20221026112438.236336-1-a.naribayashi@fujitsu.com
Fixes: 6e2b7044c199 ("mm, compaction: make fast_isolate_freepages() stay within zone").
Signed-off-by: NARIBAYASHI Akira <a.naribayashi@fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Baolin Wang
|
fccee93eb2 |
mm/hugetlb: fix races when looking up a CONT-PTE/PMD size hugetlb page
commit fac35ba763ed07ba93154c95ffc0c4a55023707f upstream. On some architectures (like ARM64), it can support CONT-PTE/PMD size hugetlb, which means it can support not only PMD/PUD size hugetlb (2M and 1G), but also CONT-PTE/PMD size(64K and 32M) if a 4K page size specified. So when looking up a CONT-PTE size hugetlb page by follow_page(), it will use pte_offset_map_lock() to get the pte entry lock for the CONT-PTE size hugetlb in follow_page_pte(). However this pte entry lock is incorrect for the CONT-PTE size hugetlb, since we should use huge_pte_lock() to get the correct lock, which is mm->page_table_lock. That means the pte entry of the CONT-PTE size hugetlb under current pte lock is unstable in follow_page_pte(), we can continue to migrate or poison the pte entry of the CONT-PTE size hugetlb, which can cause some potential race issues, even though they are under the 'pte lock'. For example, suppose thread A is trying to look up a CONT-PTE size hugetlb page by move_pages() syscall under the lock, however antoher thread B can migrate the CONT-PTE hugetlb page at the same time, which will cause thread A to get an incorrect page, if thread A also wants to do page migration, then data inconsistency error occurs. Moreover we have the same issue for CONT-PMD size hugetlb in follow_huge_pmd(). To fix above issues, rename the follow_huge_pmd() as follow_huge_pmd_pte() to handle PMD and PTE level size hugetlb, which uses huge_pte_lock() to get the correct pte entry lock to make the pte entry stable. Mike said: Support for CONT_PMD/_PTE was added with |
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John Starks
|
f1cf856123 |
mm/gup: fix gup_pud_range() for dax
commit fcd0ccd836ffad73d98a66f6fea7b16f735ea920 upstream. For dax pud, pud_huge() returns true on x86. So the function works as long as hugetlb is configured. However, dax doesn't depend on hugetlb. Commit |
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Tejun Heo
|
f1f7f36cf6 |
memcg: fix possible use-after-free in memcg_write_event_control()
commit 4a7ba45b1a435e7097ca0f79a847d0949d0eb088 upstream. memcg_write_event_control() accesses the dentry->d_name of the specified control fd to route the write call. As a cgroup interface file can't be renamed, it's safe to access d_name as long as the specified file is a regular cgroup file. Also, as these cgroup interface files can't be removed before the directory, it's safe to access the parent too. Prior to |
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Jann Horn
|
7f445ca2e0 |
mm/khugepaged: invoke MMU notifiers in shmem/file collapse paths
commit f268f6cf875f3220afc77bdd0bf1bb136eb54db9 upstream. Any codepath that zaps page table entries must invoke MMU notifiers to ensure that secondary MMUs (like KVM) don't keep accessing pages which aren't mapped anymore. Secondary MMUs don't hold their own references to pages that are mirrored over, so failing to notify them can lead to page use-after-free. I'm marking this as addressing an issue introduced in commit |
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Jann Horn
|
4a1cdb49d0 |
mm/khugepaged: fix GUP-fast interaction by sending IPI
commit 2ba99c5e08812494bc57f319fb562f527d9bacd8 upstream.
Since commit 70cbc3cc78a99 ("mm: gup: fix the fast GUP race against THP
collapse"), the lockless_pages_from_mm() fastpath rechecks the pmd_t to
ensure that the page table was not removed by khugepaged in between.
However, lockless_pages_from_mm() still requires that the page table is
not concurrently freed. Fix it by sending IPIs (if the architecture uses
semi-RCU-style page table freeing) before freeing/reusing page tables.
Link: https://lkml.kernel.org/r/20221129154730.2274278-2-jannh@google.com
Link: https://lkml.kernel.org/r/20221128180252.1684965-2-jannh@google.com
Link: https://lkml.kernel.org/r/20221125213714.4115729-2-jannh@google.com
Fixes:
|
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Jann Horn
|
cdfd3739b2 |
mm/khugepaged: take the right locks for page table retraction
commit 8d3c106e19e8d251da31ff4cc7462e4565d65084 upstream.
pagetable walks on address ranges mapped by VMAs can be done under the
mmap lock, the lock of an anon_vma attached to the VMA, or the lock of the
VMA's address_space. Only one of these needs to be held, and it does not
need to be held in exclusive mode.
Under those circumstances, the rules for concurrent access to page table
entries are:
- Terminal page table entries (entries that don't point to another page
table) can be arbitrarily changed under the page table lock, with the
exception that they always need to be consistent for
hardware page table walks and lockless_pages_from_mm().
This includes that they can be changed into non-terminal entries.
- Non-terminal page table entries (which point to another page table)
can not be modified; readers are allowed to READ_ONCE() an entry, verify
that it is non-terminal, and then assume that its value will stay as-is.
Retracting a page table involves modifying a non-terminal entry, so
page-table-level locks are insufficient to protect against concurrent page
table traversal; it requires taking all the higher-level locks under which
it is possible to start a page walk in the relevant range in exclusive
mode.
The collapse_huge_page() path for anonymous THP already follows this rule,
but the shmem/file THP path was getting it wrong, making it possible for
concurrent rmap-based operations to cause corruption.
Link: https://lkml.kernel.org/r/20221129154730.2274278-1-jannh@google.com
Link: https://lkml.kernel.org/r/20221128180252.1684965-1-jannh@google.com
Link: https://lkml.kernel.org/r/20221125213714.4115729-1-jannh@google.com
Fixes:
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Linus Torvalds
|
d072a10c81 |
v4l2: don't fall back to follow_pfn() if pin_user_pages_fast() fails
commit 6647e76ab623b2b3fb2efe03a86e9c9046c52c33 upstream.
The V4L2_MEMORY_USERPTR interface is long deprecated and shouldn't be
used (and is discouraged for any modern v4l drivers). And Seth Jenkins
points out that the fallback to VM_PFNMAP/VM_IO is fundamentally racy
and dangerous.
Note that it's not even a case that should trigger, since any normal
user pointer logic ends up just using the pin_user_pages_fast() call
that does the proper page reference counting. That's not the problem
case, only if you try to use special device mappings do you have any
issues.
Normally I'd just remove this during the merge window, but since Seth
pointed out the problem cases, we really want to know as soon as
possible if there are actually any users of this odd special case of a
legacy interface. Neither Hans nor Mauro seem to think that such
mis-uses of the old legacy interface should exist. As Mauro says:
"See, V4L2 has actually 4 streaming APIs:
- Kernel-allocated mmap (usually referred simply as just mmap);
- USERPTR mmap;
- read();
- dmabuf;
The USERPTR is one of the oldest way to use it, coming from V4L
version 1 times, and by far the least used one"
And Hans chimed in on the USERPTR interface:
"To be honest, I wouldn't mind if it goes away completely, but that's a
bit of a pipe dream right now"
but while removing this legacy interface entirely may be a pipe dream we
can at least try to remove the unlikely (and actively broken) case of
using special device mappings for USERPTR accesses.
This replaces it with a WARN_ONCE() that we can remove once we've
hopefully confirmed that no actual users exist.
NOTE! Longer term, this means that a 'struct frame_vector' only ever
contains proper page pointers, and all the games we have with converting
them to pages can go away (grep for 'frame_vector_to_pages()' and the
uses of 'vec->is_pfns'). But this is just the first step, to verify
that this code really is all dead, and do so as quickly as possible.
Reported-by: Seth Jenkins <sethjenkins@google.com>
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
Acked-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Johannes Weiner
|
d925dd3e44 |
mm: vmscan: fix extreme overreclaim and swap floods
commit f53af4285d775cd9a9a146fc438bd0a1bee1838a upstream.
During proactive reclaim, we sometimes observe severe overreclaim, with
several thousand times more pages reclaimed than requested.
This trace was obtained from shrink_lruvec() during such an instance:
prio:0 anon_cost:1141521 file_cost:7767
nr_reclaimed:4387406 nr_to_reclaim:1047 (or_factor:4190)
nr=[7161123 345 578 1111]
While he reclaimer requested 4M, vmscan reclaimed close to 16G, most of it
by swapping. These requests take over a minute, during which the write()
to memory.reclaim is unkillably stuck inside the kernel.
Digging into the source, this is caused by the proportional reclaim
bailout logic. This code tries to resolve a fundamental conflict: to
reclaim roughly what was requested, while also aging all LRUs fairly and
in accordance to their size, swappiness, refault rates etc. The way it
attempts fairness is that once the reclaim goal has been reached, it stops
scanning the LRUs with the smaller remaining scan targets, and adjusts the
remainder of the bigger LRUs according to how much of the smaller LRUs was
scanned. It then finishes scanning that remainder regardless of the
reclaim goal.
This works fine if priority levels are low and the LRU lists are
comparable in size. However, in this instance, the cgroup that is
targeted by proactive reclaim has almost no files left - they've already
been squeezed out by proactive reclaim earlier - and the remaining anon
pages are hot. Anon rotations cause the priority level to drop to 0,
which results in reclaim targeting all of anon (a lot) and all of file
(almost nothing). By the time reclaim decides to bail, it has scanned
most or all of the file target, and therefor must also scan most or all of
the enormous anon target. This target is thousands of times larger than
the reclaim goal, thus causing the overreclaim.
The bailout code hasn't changed in years, why is this failing now? The
most likely explanations are two other recent changes in anon reclaim:
1. Before the series starting with commit
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Alexander Potapenko
|
294ef12dcc |
mm: fs: initialize fsdata passed to write_begin/write_end interface
commit 1468c6f4558b1bcd92aa0400f2920f9dc7588402 upstream. Functions implementing the a_ops->write_end() interface accept the `void *fsdata` parameter that is supposed to be initialized by the corresponding a_ops->write_begin() (which accepts `void **fsdata`). However not all a_ops->write_begin() implementations initialize `fsdata` unconditionally, so it may get passed uninitialized to a_ops->write_end(), resulting in undefined behavior. Fix this by initializing fsdata with NULL before the call to write_begin(), rather than doing so in all possible a_ops implementations. This patch covers only the following cases found by running x86 KMSAN under syzkaller: - generic_perform_write() - cont_expand_zero() and generic_cont_expand_simple() - page_symlink() Other cases of passing uninitialized fsdata may persist in the codebase. Link: https://lkml.kernel.org/r/20220915150417.722975-43-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Eric Biggers <ebiggers@kernel.org> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Ilya Leoshkevich <iii@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Marco Elver <elver@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Alban Crequy
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db744288af |
maccess: Fix writing offset in case of fault in strncpy_from_kernel_nofault()
commit 8678ea06852cd1f819b870c773d43df888d15d46 upstream.
If a page fault occurs while copying the first byte, this function resets one
byte before dst.
As a consequence, an address could be modified and leaded to kernel crashes if
case the modified address was accessed later.
Fixes:
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Pankaj Gupta
|
0b692d41ee |
mm/memremap.c: map FS_DAX device memory as decrypted
commit 867400af90f1f953ff9e10b1b87ecaf9369a7eb8 upstream.
virtio_pmem use devm_memremap_pages() to map the device memory. By
default this memory is mapped as encrypted with SEV. Guest reboot changes
the current encryption key and guest no longer properly decrypts the FSDAX
device meta data.
Mark the corresponding device memory region for FSDAX devices (mapped with
memremap_pages) as decrypted to retain the persistent memory property.
Link: https://lkml.kernel.org/r/20221102160728.3184016-1-pankaj.gupta@amd.com
Fixes:
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Rik van Riel
|
568e3812b1 |
mm,hugetlb: take hugetlb_lock before decrementing h->resv_huge_pages
commit 12df140f0bdfae5dcfc81800970dd7f6f632e00c upstream.
The h->*_huge_pages counters are protected by the hugetlb_lock, but
alloc_huge_page has a corner case where it can decrement the counter
outside of the lock.
This could lead to a corrupted value of h->resv_huge_pages, which we have
observed on our systems.
Take the hugetlb_lock before decrementing h->resv_huge_pages to avoid a
potential race.
Link: https://lkml.kernel.org/r/20221017202505.0e6a4fcd@imladris.surriel.com
Fixes:
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Yuanzheng Song
|
935a8b6202 |
mm/memory: add non-anonymous page check in the copy_present_page()
The vma->anon_vma of the child process may be NULL because
the entire vma does not contain anonymous pages. In this
case, a BUG will occur when the copy_present_page() passes
a copy of a non-anonymous page of that vma to the
page_add_new_anon_rmap() to set up new anonymous rmap.
------------[ cut here ]------------
kernel BUG at mm/rmap.c:1044!
Internal error: Oops - BUG: 0 [#1] SMP
Modules linked in:
CPU: 2 PID: 3617 Comm: test Not tainted 5.10.149 #1
Hardware name: linux,dummy-virt (DT)
pstate: 80000005 (Nzcv daif -PAN -UAO -TCO BTYPE=--)
pc : __page_set_anon_rmap+0xbc/0xf8
lr : __page_set_anon_rmap+0xbc/0xf8
sp : ffff800014c1b870
x29: ffff800014c1b870 x28: 0000000000000001
x27: 0000000010100073 x26: ffff1d65c517baa8
x25: ffff1d65cab0f000 x24: ffff1d65c416d800
x23: ffff1d65cab5f248 x22: 0000000020000000
x21: 0000000000000001 x20: 0000000000000000
x19: fffffe75970023c0 x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000
x15: 0000000000000000 x14: 0000000000000000
x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000000000
x9 : ffffc3096d5fb858 x8 : 0000000000000000
x7 : 0000000000000011 x6 : ffff5a5c9089c000
x5 : 0000000000020000 x4 : ffff5a5c9089c000
x3 : ffffc3096d200000 x2 : ffffc3096e8d0000
x1 : ffff1d65ca3da740 x0 : 0000000000000000
Call trace:
__page_set_anon_rmap+0xbc/0xf8
page_add_new_anon_rmap+0x1e0/0x390
copy_pte_range+0xd00/0x1248
copy_page_range+0x39c/0x620
dup_mmap+0x2e0/0x5a8
dup_mm+0x78/0x140
copy_process+0x918/0x1a20
kernel_clone+0xac/0x638
__do_sys_clone+0x78/0xb0
__arm64_sys_clone+0x30/0x40
el0_svc_common.constprop.0+0xb0/0x308
do_el0_svc+0x48/0xb8
el0_svc+0x24/0x38
el0_sync_handler+0x160/0x168
el0_sync+0x180/0x1c0
Code: 97f8ff85 f9400294 17ffffeb 97f8ff82 (d4210000)
---[ end trace a972347688dc9bd4 ]---
Kernel panic - not syncing: Oops - BUG: Fatal exception
SMP: stopping secondary CPUs
Kernel Offset: 0x43095d200000 from 0xffff800010000000
PHYS_OFFSET: 0xffffe29a80000000
CPU features: 0x08200022,61806082
Memory Limit: none
---[ end Kernel panic - not syncing: Oops - BUG: Fatal exception ]---
This problem has been fixed by the commit <fb3d824d1a46>
("mm/rmap: split page_dup_rmap() into page_dup_file_rmap()
and page_try_dup_anon_rmap()"), but still exists in the
linux-5.10.y branch.
This patch is not applicable to this version because
of the large version differences. Therefore, fix it by
adding non-anonymous page check in the copy_present_page().
Cc: stable@vger.kernel.org
Fixes:
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Liu Shixin
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45c3396675 |
mm: hugetlb: fix UAF in hugetlb_handle_userfault
commit 958f32ce832ba781ac20e11bb2d12a9352ea28fc upstream.
The vma_lock and hugetlb_fault_mutex are dropped before handling userfault
and reacquire them again after handle_userfault(), but reacquire the
vma_lock could lead to UAF[1,2] due to the following race,
hugetlb_fault
hugetlb_no_page
/*unlock vma_lock */
hugetlb_handle_userfault
handle_userfault
/* unlock mm->mmap_lock*/
vm_mmap_pgoff
do_mmap
mmap_region
munmap_vma_range
/* clean old vma */
/* lock vma_lock again <--- UAF */
/* unlock vma_lock */
Since the vma_lock will unlock immediately after
hugetlb_handle_userfault(), let's drop the unneeded lock and unlock in
hugetlb_handle_userfault() to fix the issue.
[1] https://lore.kernel.org/linux-mm/000000000000d5e00a05e834962e@google.com/
[2] https://lore.kernel.org/linux-mm/20220921014457.1668-1-liuzixian4@huawei.com/
Link: https://lkml.kernel.org/r/20220923042113.137273-1-liushixin2@huawei.com
Fixes:
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Carlos Llamas
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a3c08c0217 |
mm/mmap: undo ->mmap() when arch_validate_flags() fails
commit deb0f6562884b5b4beb883d73e66a7d3a1b96d99 upstream. Commit |
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Yang Shi
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377c60dd32 |
mm: gup: fix the fast GUP race against THP collapse
commit 70cbc3cc78a997d8247b50389d37c4e1736019da upstream. Since general RCU GUP fast was introduced in commit |
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Minchan Kim
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be2cd261ca |
mm: fix madivse_pageout mishandling on non-LRU page
commit 58d426a7ba92870d489686dfdb9d06b66815a2ab upstream.
MADV_PAGEOUT tries to isolate non-LRU pages and gets a warning from
isolate_lru_page below.
Fix it by checking PageLRU in advance.
------------[ cut here ]------------
trying to isolate tail page
WARNING: CPU: 0 PID: 6175 at mm/folio-compat.c:158 isolate_lru_page+0x130/0x140
Modules linked in:
CPU: 0 PID: 6175 Comm: syz-executor.0 Not tainted 5.18.12 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:isolate_lru_page+0x130/0x140
Link: https://lore.kernel.org/linux-mm/485f8c33.2471b.182d5726afb.Coremail.hantianshuo@iie.ac.cn/
Link: https://lkml.kernel.org/r/20220908151204.762596-1-minchan@kernel.org
Fixes:
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Alistair Popple
|
1002d5fef4 |
mm/migrate_device.c: flush TLB while holding PTL
commit 60bae73708963de4a17231077285bd9ff2f41c44 upstream.
When clearing a PTE the TLB should be flushed whilst still holding the PTL
to avoid a potential race with madvise/munmap/etc. For example consider
the following sequence:
CPU0 CPU1
---- ----
migrate_vma_collect_pmd()
pte_unmap_unlock()
madvise(MADV_DONTNEED)
-> zap_pte_range()
pte_offset_map_lock()
[ PTE not present, TLB not flushed ]
pte_unmap_unlock()
[ page is still accessible via stale TLB ]
flush_tlb_range()
In this case the page may still be accessed via the stale TLB entry after
madvise returns. Fix this by flushing the TLB while holding the PTL.
Fixes:
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Maurizio Lombardi
|
a54fc53691 |
mm: prevent page_frag_alloc() from corrupting the memory
commit dac22531bbd4af2426c4e29e05594415ccfa365d upstream.
A number of drivers call page_frag_alloc() with a fragment's size >
PAGE_SIZE.
In low memory conditions, __page_frag_cache_refill() may fail the order
3 cache allocation and fall back to order 0; In this case, the cache
will be smaller than the fragment, causing memory corruptions.
Prevent this from happening by checking if the newly allocated cache is
large enough for the fragment; if not, the allocation will fail and
page_frag_alloc() will return NULL.
Link: https://lkml.kernel.org/r/20220715125013.247085-1-mlombard@redhat.com
Fixes:
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Mel Gorman
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466a26af2d |
mm/page_alloc: fix race condition between build_all_zonelists and page allocation
commit 3d36424b3b5850bd92f3e89b953a430d7cfc88ef upstream. Patrick Daly reported the following problem; NODE_DATA(nid)->node_zonelists[ZONELIST_FALLBACK] - before offline operation [0] - ZONE_MOVABLE [1] - ZONE_NORMAL [2] - NULL For a GFP_KERNEL allocation, alloc_pages_slowpath() will save the offset of ZONE_NORMAL in ac->preferred_zoneref. If a concurrent memory_offline operation removes the last page from ZONE_MOVABLE, build_all_zonelists() & build_zonerefs_node() will update node_zonelists as shown below. Only populated zones are added. NODE_DATA(nid)->node_zonelists[ZONELIST_FALLBACK] - after offline operation [0] - ZONE_NORMAL [1] - NULL [2] - NULL The race is simple -- page allocation could be in progress when a memory hot-remove operation triggers a zonelist rebuild that removes zones. The allocation request will still have a valid ac->preferred_zoneref that is now pointing to NULL and triggers an OOM kill. This problem probably always existed but may be slightly easier to trigger due to |
||
|
Chao Yu
|
379ac7905f |
mm/slub: fix to return errno if kmalloc() fails
commit 7e9c323c52b379d261a72dc7bd38120a761a93cd upstream.
In create_unique_id(), kmalloc(, GFP_KERNEL) can fail due to
out-of-memory, if it fails, return errno correctly rather than
triggering panic via BUG_ON();
kernel BUG at mm/slub.c:5893!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
Call trace:
sysfs_slab_add+0x258/0x260 mm/slub.c:5973
__kmem_cache_create+0x60/0x118 mm/slub.c:4899
create_cache mm/slab_common.c:229 [inline]
kmem_cache_create_usercopy+0x19c/0x31c mm/slab_common.c:335
kmem_cache_create+0x1c/0x28 mm/slab_common.c:390
f2fs_kmem_cache_create fs/f2fs/f2fs.h:2766 [inline]
f2fs_init_xattr_caches+0x78/0xb4 fs/f2fs/xattr.c:808
f2fs_fill_super+0x1050/0x1e0c fs/f2fs/super.c:4149
mount_bdev+0x1b8/0x210 fs/super.c:1400
f2fs_mount+0x44/0x58 fs/f2fs/super.c:4512
legacy_get_tree+0x30/0x74 fs/fs_context.c:610
vfs_get_tree+0x40/0x140 fs/super.c:1530
do_new_mount+0x1dc/0x4e4 fs/namespace.c:3040
path_mount+0x358/0x914 fs/namespace.c:3370
do_mount fs/namespace.c:3383 [inline]
__do_sys_mount fs/namespace.c:3591 [inline]
__se_sys_mount fs/namespace.c:3568 [inline]
__arm64_sys_mount+0x2f8/0x408 fs/namespace.c:3568
Cc: <stable@kernel.org>
Fixes:
|
||
|
Jann Horn
|
891f03f688 |
mm: Fix TLB flush for not-first PFNMAP mappings in unmap_region()
This is a stable-specific patch.
I botched the stable-specific rewrite of
commit b67fbebd4cf98 ("mmu_gather: Force tlb-flush VM_PFNMAP vmas"):
As Hugh pointed out, unmap_region() actually operates on a list of VMAs,
and the variable "vma" merely points to the first VMA in that list.
So if we want to check whether any of the VMAs we're operating on is
PFNMAP or MIXEDMAP, we have to iterate through the list and check each VMA.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
||
|
Yee Lee
|
a14f1799ce |
Revert "mm: kmemleak: take a full lowmem check in kmemleak_*_phys()"
This reverts commit 23c2d497de21f25898fbea70aeb292ab8acc8c94.
Commit 23c2d497de21 ("mm: kmemleak: take a full lowmem check in
kmemleak_*_phys()") brought false leak alarms on some archs like arm64
that does not init pfn boundary in early booting. The final solution
lands on linux-6.0: commit 0c24e061196c ("mm: kmemleak: add rbtree and
store physical address for objects allocated with PA").
Revert this commit before linux-6.0. The original issue of invalid PA
can be mitigated by additional check in devicetree.
The false alarm report is as following: Kmemleak output: (Qemu/arm64)
unreferenced object 0xffff0000c0170a00 (size 128):
comm "swapper/0", pid 1, jiffies 4294892404 (age 126.208s)
hex dump (first 32 bytes):
62 61 73 65 00 00 00 00 00 00 00 00 00 00 00 00 base............
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<(____ptrval____)>] __kmalloc_track_caller+0x1b0/0x2e4
[<(____ptrval____)>] kstrdup_const+0x8c/0xc4
[<(____ptrval____)>] kvasprintf_const+0xbc/0xec
[<(____ptrval____)>] kobject_set_name_vargs+0x58/0xe4
[<(____ptrval____)>] kobject_add+0x84/0x100
[<(____ptrval____)>] __of_attach_node_sysfs+0x78/0xec
[<(____ptrval____)>] of_core_init+0x68/0x104
[<(____ptrval____)>] driver_init+0x28/0x48
[<(____ptrval____)>] do_basic_setup+0x14/0x28
[<(____ptrval____)>] kernel_init_freeable+0x110/0x178
[<(____ptrval____)>] kernel_init+0x20/0x1a0
[<(____ptrval____)>] ret_from_fork+0x10/0x20
This pacth is also applicable to linux-5.17.y/linux-5.18.y/linux-5.19.y
Cc: <stable@vger.kernel.org>
Signed-off-by: Yee Lee <yee.lee@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
||
|
Steven Price
|
47a73e5e6b |
mm: pagewalk: Fix race between unmap and page walker
[ Upstream commit 8782fb61cc848364e1e1599d76d3c9dd58a1cc06 ]
The mmap lock protects the page walker from changes to the page tables
during the walk. However a read lock is insufficient to protect those
areas which don't have a VMA as munmap() detaches the VMAs before
downgrading to a read lock and actually tearing down PTEs/page tables.
For users of walk_page_range() the solution is to simply call pte_hole()
immediately without checking the actual page tables when a VMA is not
present. We now never call __walk_page_range() without a valid vma.
For walk_page_range_novma() the locking requirements are tightened to
require the mmap write lock to be taken, and then walking the pgd
directly with 'no_vma' set.
This in turn means that all page walkers either have a valid vma, or
it's that special 'novma' case for page table debugging. As a result,
all the odd '(!walk->vma && !walk->no_vma)' tests can be removed.
Fixes:
|
||
|
Jann Horn
|
98f401d363 |
mm/rmap: Fix anon_vma->degree ambiguity leading to double-reuse
commit 2555283eb40df89945557273121e9393ef9b542b upstream.
anon_vma->degree tracks the combined number of child anon_vmas and VMAs
that use the anon_vma as their ->anon_vma.
anon_vma_clone() then assumes that for any anon_vma attached to
src->anon_vma_chain other than src->anon_vma, it is impossible for it to
be a leaf node of the VMA tree, meaning that for such VMAs ->degree is
elevated by 1 because of a child anon_vma, meaning that if ->degree
equals 1 there are no VMAs that use the anon_vma as their ->anon_vma.
This assumption is wrong because the ->degree optimization leads to leaf
nodes being abandoned on anon_vma_clone() - an existing anon_vma is
reused and no new parent-child relationship is created. So it is
possible to reuse an anon_vma for one VMA while it is still tied to
another VMA.
This is an issue because is_mergeable_anon_vma() and its callers assume
that if two VMAs have the same ->anon_vma, the list of anon_vmas
attached to the VMAs is guaranteed to be the same. When this assumption
is violated, vma_merge() can merge pages into a VMA that is not attached
to the corresponding anon_vma, leading to dangling page->mapping
pointers that will be dereferenced during rmap walks.
Fix it by separately tracking the number of child anon_vmas and the
number of VMAs using the anon_vma as their ->anon_vma.
Fixes:
|
||
|
Jann Horn
|
895428ee12 |
mm: Force TLB flush for PFNMAP mappings before unlink_file_vma()
commit b67fbebd4cf980aecbcc750e1462128bffe8ae15 upstream.
Some drivers rely on having all VMAs through which a PFN might be
accessible listed in the rmap for correctness.
However, on X86, it was possible for a VMA with stale TLB entries
to not be listed in the rmap.
This was fixed in mainline with
commit b67fbebd4cf9 ("mmu_gather: Force tlb-flush VM_PFNMAP vmas"),
but that commit relies on preceding refactoring in
commit 18ba064e42df3 ("mmu_gather: Let there be one tlb_{start,end}_vma()
implementation") and commit 1e9fdf21a4339 ("mmu_gather: Remove per arch
tlb_{start,end}_vma()").
This patch provides equivalent protection without needing that
refactoring, by forcing a TLB flush between removing PTEs in
unmap_vmas() and the call to unlink_file_vma() in free_pgtables().
[This is a stable-specific rewrite of the upstream commit!]
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
||
|
David Hildenbrand
|
62af37c5cd |
mm/hugetlb: fix hugetlb not supporting softdirty tracking
commit f96f7a40874d7c746680c0b9f57cef2262ae551f upstream.
Patch series "mm/hugetlb: fix write-fault handling for shared mappings", v2.
I observed that hugetlb does not support/expect write-faults in shared
mappings that would have to map the R/O-mapped page writable -- and I
found two case where we could currently get such faults and would
erroneously map an anon page into a shared mapping.
Reproducers part of the patches.
I propose to backport both fixes to stable trees. The first fix needs a
small adjustment.
This patch (of 2):
Staring at hugetlb_wp(), one might wonder where all the logic for shared
mappings is when stumbling over a write-protected page in a shared
mapping. In fact, there is none, and so far we thought we could get away
with that because e.g., mprotect() should always do the right thing and
map all pages directly writable.
Looks like we were wrong:
--------------------------------------------------------------------------
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <sys/mman.h>
#define HUGETLB_SIZE (2 * 1024 * 1024u)
static void clear_softdirty(void)
{
int fd = open("/proc/self/clear_refs", O_WRONLY);
const char *ctrl = "4";
int ret;
if (fd < 0) {
fprintf(stderr, "open(clear_refs) failed\n");
exit(1);
}
ret = write(fd, ctrl, strlen(ctrl));
if (ret != strlen(ctrl)) {
fprintf(stderr, "write(clear_refs) failed\n");
exit(1);
}
close(fd);
}
int main(int argc, char **argv)
{
char *map;
int fd;
fd = open("/dev/hugepages/tmp", O_RDWR | O_CREAT);
if (!fd) {
fprintf(stderr, "open() failed\n");
return -errno;
}
if (ftruncate(fd, HUGETLB_SIZE)) {
fprintf(stderr, "ftruncate() failed\n");
return -errno;
}
map = mmap(NULL, HUGETLB_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
if (map == MAP_FAILED) {
fprintf(stderr, "mmap() failed\n");
return -errno;
}
*map = 0;
if (mprotect(map, HUGETLB_SIZE, PROT_READ)) {
fprintf(stderr, "mmprotect() failed\n");
return -errno;
}
clear_softdirty();
if (mprotect(map, HUGETLB_SIZE, PROT_READ|PROT_WRITE)) {
fprintf(stderr, "mmprotect() failed\n");
return -errno;
}
*map = 0;
return 0;
}
--------------------------------------------------------------------------
Above test fails with SIGBUS when there is only a single free hugetlb page.
# echo 1 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
# ./test
Bus error (core dumped)
And worse, with sufficient free hugetlb pages it will map an anonymous page
into a shared mapping, for example, messing up accounting during unmap
and breaking MAP_SHARED semantics:
# echo 2 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
# ./test
# cat /proc/meminfo | grep HugePages_
HugePages_Total: 2
HugePages_Free: 1
HugePages_Rsvd: 18446744073709551615
HugePages_Surp: 0
Reason in this particular case is that vma_wants_writenotify() will
return "true", removing VM_SHARED in vma_set_page_prot() to map pages
write-protected. Let's teach vma_wants_writenotify() that hugetlb does not
support softdirty tracking.
Link: https://lkml.kernel.org/r/20220811103435.188481-1-david@redhat.com
Link: https://lkml.kernel.org/r/20220811103435.188481-2-david@redhat.com
Fixes:
|
||
|
Miaohe Lin
|
c7c77185fa |
mm/huge_memory.c: use helper function migration_entry_to_page()
[ Upstream commit a44f89dc6c5f8ba70240b81a570260d29d04bcb0 ] It's more recommended to use helper function migration_entry_to_page() to get the page via migration entry. We can also enjoy the PageLocked() check there. Link: https://lkml.kernel.org/r/20210318122722.13135-7-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Peter Xu <peterx@redhat.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michel Lespinasse <walken@google.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Thomas Hellstrm (Intel) <thomas_os@shipmail.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: William Kucharski <william.kucharski@oracle.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: yuleixzhang <yulei.kernel@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> |
||
|
Miaohe Lin
|
4ffa6cecb5 |
mm/mmap.c: fix missing call to vm_unacct_memory in mmap_region
[ Upstream commit 7f82f922319ede486540e8746769865b9508d2c2 ] Since the beginning, charged is set to 0 to avoid calling vm_unacct_memory twice because vm_unacct_memory will be called by above unmap_region. But since commit |
||
|
Aneesh Kumar K.V
|
2613baa3ab |
mm/mremap: hold the rmap lock in write mode when moving page table entries.
commit 97113eb39fa7972722ff490b947d8af023e1f6a2 upstream. To avoid a race between rmap walk and mremap, mremap does take_rmap_locks(). The lock was taken to ensure that rmap walk don't miss a page table entry due to PTE moves via move_pagetables(). The kernel does further optimization of this lock such that if we are going to find the newly added vma after the old vma, the rmap lock is not taken. This is because rmap walk would find the vmas in the same order and if we don't find the page table attached to older vma we would find it with the new vma which we would iterate later. As explained in commit |
||
|
Dave Chinner
|
f5f3e54f81 |
mm: Add kvrealloc()
commit de2860f4636256836450c6543be744a50118fc66 upstream.
During log recovery of an XFS filesystem with 64kB directory
buffers, rebuilding a buffer split across two log records results
in a memory allocation warning from krealloc like this:
xfs filesystem being mounted at /mnt/scratch supports timestamps until 2038 (0x7fffffff)
XFS (dm-0): Unmounting Filesystem
XFS (dm-0): Mounting V5 Filesystem
XFS (dm-0): Starting recovery (logdev: internal)
------------[ cut here ]------------
WARNING: CPU: 5 PID: 3435170 at mm/page_alloc.c:3539 get_page_from_freelist+0xdee/0xe40
.....
RIP: 0010:get_page_from_freelist+0xdee/0xe40
Call Trace:
? complete+0x3f/0x50
__alloc_pages+0x16f/0x300
alloc_pages+0x87/0x110
kmalloc_order+0x2c/0x90
kmalloc_order_trace+0x1d/0x90
__kmalloc_track_caller+0x215/0x270
? xlog_recover_add_to_cont_trans+0x63/0x1f0
krealloc+0x54/0xb0
xlog_recover_add_to_cont_trans+0x63/0x1f0
xlog_recovery_process_trans+0xc1/0xd0
xlog_recover_process_ophdr+0x86/0x130
xlog_recover_process_data+0x9f/0x160
xlog_recover_process+0xa2/0x120
xlog_do_recovery_pass+0x40b/0x7d0
? __irq_work_queue_local+0x4f/0x60
? irq_work_queue+0x3a/0x50
xlog_do_log_recovery+0x70/0x150
xlog_do_recover+0x38/0x1d0
xlog_recover+0xd8/0x170
xfs_log_mount+0x181/0x300
xfs_mountfs+0x4a1/0x9b0
xfs_fs_fill_super+0x3c0/0x7b0
get_tree_bdev+0x171/0x270
? suffix_kstrtoint.constprop.0+0xf0/0xf0
xfs_fs_get_tree+0x15/0x20
vfs_get_tree+0x24/0xc0
path_mount+0x2f5/0xaf0
__x64_sys_mount+0x108/0x140
do_syscall_64+0x3a/0x70
entry_SYSCALL_64_after_hwframe+0x44/0xae
Essentially, we are taking a multi-order allocation from kmem_alloc()
(which has an open coded no fail, no warn loop) and then
reallocating it out to 64kB using krealloc(__GFP_NOFAIL) and that is
then triggering the above warning.
This is a regression caused by converting this code from an open
coded no fail/no warn reallocation loop to using __GFP_NOFAIL.
What we actually need here is kvrealloc(), so that if contiguous
page allocation fails we fall back to vmalloc() and we don't
get nasty warnings happening in XFS.
Fixes:
|
||
|
Jaewon Kim
|
2670f76a56 |
page_alloc: fix invalid watermark check on a negative value
commit 9282012fc0aa248b77a69f5eb802b67c5a16bb13 upstream. There was a report that a task is waiting at the throttle_direct_reclaim. The pgscan_direct_throttle in vmstat was increasing. This is a bug where zone_watermark_fast returns true even when the free is very low. The commit |
||
|
Wang Cheng
|
ddb3f0b688 |
mm/mempolicy: fix uninit-value in mpol_rebind_policy()
commit 018160ad314d75b1409129b2247b614a9f35894c upstream. mpol_set_nodemask()(mm/mempolicy.c) does not set up nodemask when pol->mode is MPOL_LOCAL. Check pol->mode before access pol->w.cpuset_mems_allowed in mpol_rebind_policy()(mm/mempolicy.c). BUG: KMSAN: uninit-value in mpol_rebind_policy mm/mempolicy.c:352 [inline] BUG: KMSAN: uninit-value in mpol_rebind_task+0x2ac/0x2c0 mm/mempolicy.c:368 mpol_rebind_policy mm/mempolicy.c:352 [inline] mpol_rebind_task+0x2ac/0x2c0 mm/mempolicy.c:368 cpuset_change_task_nodemask kernel/cgroup/cpuset.c:1711 [inline] cpuset_attach+0x787/0x15e0 kernel/cgroup/cpuset.c:2278 cgroup_migrate_execute+0x1023/0x1d20 kernel/cgroup/cgroup.c:2515 cgroup_migrate kernel/cgroup/cgroup.c:2771 [inline] cgroup_attach_task+0x540/0x8b0 kernel/cgroup/cgroup.c:2804 __cgroup1_procs_write+0x5cc/0x7a0 kernel/cgroup/cgroup-v1.c:520 cgroup1_tasks_write+0x94/0xb0 kernel/cgroup/cgroup-v1.c:539 cgroup_file_write+0x4c2/0x9e0 kernel/cgroup/cgroup.c:3852 kernfs_fop_write_iter+0x66a/0x9f0 fs/kernfs/file.c:296 call_write_iter include/linux/fs.h:2162 [inline] new_sync_write fs/read_write.c:503 [inline] vfs_write+0x1318/0x2030 fs/read_write.c:590 ksys_write+0x28b/0x510 fs/read_write.c:643 __do_sys_write fs/read_write.c:655 [inline] __se_sys_write fs/read_write.c:652 [inline] __x64_sys_write+0xdb/0x120 fs/read_write.c:652 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x44/0xae Uninit was created at: slab_post_alloc_hook mm/slab.h:524 [inline] slab_alloc_node mm/slub.c:3251 [inline] slab_alloc mm/slub.c:3259 [inline] kmem_cache_alloc+0x902/0x11c0 mm/slub.c:3264 mpol_new mm/mempolicy.c:293 [inline] do_set_mempolicy+0x421/0xb70 mm/mempolicy.c:853 kernel_set_mempolicy mm/mempolicy.c:1504 [inline] __do_sys_set_mempolicy mm/mempolicy.c:1510 [inline] __se_sys_set_mempolicy+0x44c/0xb60 mm/mempolicy.c:1507 __x64_sys_set_mempolicy+0xd8/0x110 mm/mempolicy.c:1507 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x44/0xae KMSAN: uninit-value in mpol_rebind_task (2) https://syzkaller.appspot.com/bug?id=d6eb90f952c2a5de9ea718a1b873c55cb13b59dc This patch seems to fix below bug too. KMSAN: uninit-value in mpol_rebind_mm (2) https://syzkaller.appspot.com/bug?id=f2fecd0d7013f54ec4162f60743a2b28df40926b The uninit-value is pol->w.cpuset_mems_allowed in mpol_rebind_policy(). When syzkaller reproducer runs to the beginning of mpol_new(), mpol_new() mm/mempolicy.c do_mbind() mm/mempolicy.c kernel_mbind() mm/mempolicy.c `mode` is 1(MPOL_PREFERRED), nodes_empty(*nodes) is `true` and `flags` is 0. Then mode = MPOL_LOCAL; ... policy->mode = mode; policy->flags = flags; will be executed. So in mpol_set_nodemask(), mpol_set_nodemask() mm/mempolicy.c do_mbind() kernel_mbind() pol->mode is 4 (MPOL_LOCAL), that `nodemask` in `pol` is not initialized, which will be accessed in mpol_rebind_policy(). Link: https://lkml.kernel.org/r/20220512123428.fq3wofedp6oiotd4@ppc.localdomain Signed-off-by: Wang Cheng <wanngchenng@gmail.com> Reported-by: <syzbot+217f792c92599518a2ab@syzkaller.appspotmail.com> Tested-by: <syzbot+217f792c92599518a2ab@syzkaller.appspotmail.com> Cc: David Rientjes <rientjes@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
||
|
Gowans, James
|
931dbcc2e0 |
mm: split huge PUD on wp_huge_pud fallback
commit 14c99d65941538aa33edd8dc7b1bbbb593c324a2 upstream.
Currently the implementation will split the PUD when a fallback is taken
inside the create_huge_pud function. This isn't where it should be done:
the splitting should be done in wp_huge_pud, just like it's done for PMDs.
Reason being that if a callback is taken during create, there is no PUD
yet so nothing to split, whereas if a fallback is taken when encountering
a write protection fault there is something to split.
It looks like this was the original intention with the commit where the
splitting was introduced, but somehow it got moved to the wrong place
between v1 and v2 of the patch series. Rebase mistake perhaps.
Link: https://lkml.kernel.org/r/6f48d622eb8bce1ae5dd75327b0b73894a2ec407.camel@amazon.com
Fixes:
|
||
|
Jann Horn
|
6c32496964 |
mm/slub: add missing TID updates on slab deactivation
commit eeaa345e128515135ccb864c04482180c08e3259 upstream.
The fastpath in slab_alloc_node() assumes that c->slab is stable as long as
the TID stays the same. However, two places in __slab_alloc() currently
don't update the TID when deactivating the CPU slab.
If multiple operations race the right way, this could lead to an object
getting lost; or, in an even more unlikely situation, it could even lead to
an object being freed onto the wrong slab's freelist, messing up the
`inuse` counter and eventually causing a page to be freed to the page
allocator while it still contains slab objects.
(I haven't actually tested these cases though, this is just based on
looking at the code. Writing testcases for this stuff seems like it'd be
a pain...)
The race leading to state inconsistency is (all operations on the same CPU
and kmem_cache):
- task A: begin do_slab_free():
- read TID
- read pcpu freelist (==NULL)
- check `slab == c->slab` (true)
- [PREEMPT A->B]
- task B: begin slab_alloc_node():
- fastpath fails (`c->freelist` is NULL)
- enter __slab_alloc()
- slub_get_cpu_ptr() (disables preemption)
- enter ___slab_alloc()
- take local_lock_irqsave()
- read c->freelist as NULL
- get_freelist() returns NULL
- write `c->slab = NULL`
- drop local_unlock_irqrestore()
- goto new_slab
- slub_percpu_partial() is NULL
- get_partial() returns NULL
- slub_put_cpu_ptr() (enables preemption)
- [PREEMPT B->A]
- task A: finish do_slab_free():
- this_cpu_cmpxchg_double() succeeds()
- [CORRUPT STATE: c->slab==NULL, c->freelist!=NULL]
From there, the object on c->freelist will get lost if task B is allowed to
continue from here: It will proceed to the retry_load_slab label,
set c->slab, then jump to load_freelist, which clobbers c->freelist.
But if we instead continue as follows, we get worse corruption:
- task A: run __slab_free() on object from other struct slab:
- CPU_PARTIAL_FREE case (slab was on no list, is now on pcpu partial)
- task A: run slab_alloc_node() with NUMA node constraint:
- fastpath fails (c->slab is NULL)
- call __slab_alloc()
- slub_get_cpu_ptr() (disables preemption)
- enter ___slab_alloc()
- c->slab is NULL: goto new_slab
- slub_percpu_partial() is non-NULL
- set c->slab to slub_percpu_partial(c)
- [CORRUPT STATE: c->slab points to slab-1, c->freelist has objects
from slab-2]
- goto redo
- node_match() fails
- goto deactivate_slab
- existing c->freelist is passed into deactivate_slab()
- inuse count of slab-1 is decremented to account for object from
slab-2
At this point, the inuse count of slab-1 is 1 lower than it should be.
This means that if we free all allocated objects in slab-1 except for one,
SLUB will think that slab-1 is completely unused, and may free its page,
leading to use-after-free.
Fixes:
|
||
|
Mike Kravetz
|
63758dd959 |
hugetlb: fix huge_pmd_unshare address update
commit 48381273f8734d28ef56a5bdf1966dd8530111bc upstream.
The routine huge_pmd_unshare() is passed a pointer to an address
associated with an area which may be unshared. If unshare is successful
this address is updated to 'optimize' callers iterating over huge page
addresses. For the optimization to work correctly, address should be
updated to the last huge page in the unmapped/unshared area. However, in
the common case where the passed address is PUD_SIZE aligned, the address
is incorrectly updated to the address of the preceding huge page. That
wastes CPU cycles as the unmapped/unshared range is scanned twice.
Link: https://lkml.kernel.org/r/20220524205003.126184-1-mike.kravetz@oracle.com
Fixes:
|
||
|
Rei Yamamoto
|
7994d89012 |
mm, compaction: fast_find_migrateblock() should return pfn in the target zone
commit bbe832b9db2e1ad21522f8f0bf02775fff8a0e0e upstream.
At present, pages not in the target zone are added to cc->migratepages
list in isolate_migratepages_block(). As a result, pages may migrate
between nodes unintentionally.
This would be a serious problem for older kernels without commit
a984226f457f849e ("mm: memcontrol: remove the pgdata parameter of
mem_cgroup_page_lruvec"), because it can corrupt the lru list by
handling pages in list without holding proper lru_lock.
Avoid returning a pfn outside the target zone in the case that it is
not aligned with a pageblock boundary. Otherwise
isolate_migratepages_block() will handle pages not in the target zone.
Link: https://lkml.kernel.org/r/20220511044300.4069-1-yamamoto.rei@jp.fujitsu.com
Fixes:
|
||
|
Sultan Alsawaf
|
fae05b2314 |
zsmalloc: fix races between asynchronous zspage free and page migration
commit 2505a981114dcb715f8977b8433f7540854851d8 upstream.
The asynchronous zspage free worker tries to lock a zspage's entire page
list without defending against page migration. Since pages which haven't
yet been locked can concurrently migrate off the zspage page list while
lock_zspage() churns away, lock_zspage() can suffer from a few different
lethal races.
It can lock a page which no longer belongs to the zspage and unsafely
dereference page_private(), it can unsafely dereference a torn pointer to
the next page (since there's a data race), and it can observe a spurious
NULL pointer to the next page and thus not lock all of the zspage's pages
(since a single page migration will reconstruct the entire page list, and
create_page_chain() unconditionally zeroes out each list pointer in the
process).
Fix the races by using migrate_read_lock() in lock_zspage() to synchronize
with page migration.
Link: https://lkml.kernel.org/r/20220509024703.243847-1-sultan@kerneltoast.com
Fixes:
|
||
|
Jason A. Donenfeld
|
552ae8e484 |
random: move randomize_page() into mm where it belongs
commit 5ad7dd882e45d7fe432c32e896e2aaa0b21746ea upstream. randomize_page is an mm function. It is documented like one. It contains the history of one. It has the naming convention of one. It looks just like another very similar function in mm, randomize_stack_top(). And it has always been maintained and updated by mm people. There is no need for it to be in random.c. In the "which shape does not look like the other ones" test, pointing to randomize_page() is correct. So move randomize_page() into mm/util.c, right next to the similar randomize_stack_top() function. This commit contains no actual code changes. Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
||
|
Muchun Song
|
d1ac096f88 |
mm: userfaultfd: fix missing cache flush in mcopy_atomic_pte() and __mcopy_atomic()
commit 7c25a0b89a487878b0691e6524fb5a8827322194 upstream. userfaultfd calls mcopy_atomic_pte() and __mcopy_atomic() which do not do any cache flushing for the target page. Then the target page will be mapped to the user space with a different address (user address), which might have an alias issue with the kernel address used to copy the data from the user to. Fix this by insert flush_dcache_page() after copy_from_user() succeeds. Link: https://lkml.kernel.org/r/20220210123058.79206-7-songmuchun@bytedance.com Fixes: |
||
|
Muchun Song
|
c6cbf5431a |
mm: hugetlb: fix missing cache flush in copy_huge_page_from_user()
commit e763243cc6cb1fcc720ec58cfd6e7c35ae90a479 upstream.
userfaultfd calls copy_huge_page_from_user() which does not do any cache
flushing for the target page. Then the target page will be mapped to
the user space with a different address (user address), which might have
an alias issue with the kernel address used to copy the data from the
user to.
Fix this issue by flushing dcache in copy_huge_page_from_user().
Link: https://lkml.kernel.org/r/20220210123058.79206-4-songmuchun@bytedance.com
Fixes:
|
||
|
Muchun Song
|
308ff6a6e7 |
mm: fix missing cache flush for all tail pages of compound page
commit 2771739a7162782c0aa6424b2e3dd874e884a15d upstream.
The D-cache maintenance inside move_to_new_page() only consider one
page, there is still D-cache maintenance issue for tail pages of
compound page (e.g. THP or HugeTLB).
THP migration is only enabled on x86_64, ARM64 and powerpc, while
powerpc and arm64 need to maintain the consistency between I-Cache and
D-Cache, which depends on flush_dcache_page() to maintain the
consistency between I-Cache and D-Cache.
But there is no issues on arm64 and powerpc since they already considers
the compound page cache flushing in their icache flush function.
HugeTLB migration is enabled on arm, arm64, mips, parisc, powerpc,
riscv, s390 and sh, while arm has handled the compound page cache flush
in flush_dcache_page(), but most others do not.
In theory, the issue exists on many architectures. Fix this by not
using flush_dcache_folio() since it is not backportable.
Link: https://lkml.kernel.org/r/20220210123058.79206-3-songmuchun@bytedance.com
Fixes:
|
||
|
Mike Rapoport
|
9ff4a6b806 |
arm: remove CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
commit 5e545df3292fbd3d5963c68980f1527ead2a2b3f upstream.
ARM is the only architecture that defines CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
which in turn enables memmap_valid_within() function that is intended to
verify existence of struct page associated with a pfn when there are holes
in the memory map.
However, the ARCH_HAS_HOLES_MEMORYMODEL also enables HAVE_ARCH_PFN_VALID
and arch-specific pfn_valid() implementation that also deals with the holes
in the memory map.
The only two users of memmap_valid_within() call this function after
a call to pfn_valid() so the memmap_valid_within() check becomes redundant.
Remove CONFIG_ARCH_HAS_HOLES_MEMORYMODEL and memmap_valid_within() and rely
entirely on ARM's implementation of pfn_valid() that is now enabled
unconditionally.
Link: https://lkml.kernel.org/r/20201101170454.9567-9-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Meelis Roos <mroos@linux.ee>
Cc: Michael Schmitz <schmitzmic@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: kernel test robot <lkp@intel.com>
Fixes:
|
||
|
Zqiang
|
78d4dccf16 |
kasan: prevent cpu_quarantine corruption when CPU offline and cache shrink occur at same time
commit 31fa985b4196f8a66f027672e9bf2b81fea0417c upstream. kasan_quarantine_remove_cache() is called in kmem_cache_shrink()/ destroy(). The kasan_quarantine_remove_cache() call is protected by cpuslock in kmem_cache_destroy() to ensure serialization with kasan_cpu_offline(). However the kasan_quarantine_remove_cache() call is not protected by cpuslock in kmem_cache_shrink(). When a CPU is going offline and cache shrink occurs at same time, the cpu_quarantine may be corrupted by interrupt (per_cpu_remove_cache operation). So add a cpu_quarantine offline flags check in per_cpu_remove_cache(). [akpm@linux-foundation.org: add comment, per Zqiang] Link: https://lkml.kernel.org/r/20220414025925.2423818-1-qiang1.zhang@intel.com Signed-off-by: Zqiang <qiang1.zhang@intel.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
||
|
Alistair Popple
|
9ca66d7914 |
mm/mmu_notifier.c: fix race in mmu_interval_notifier_remove()
commit 319561669a59d8e9206ab311ae5433ef92fd79d1 upstream.
In some cases it is possible for mmu_interval_notifier_remove() to race
with mn_tree_inv_end() allowing it to return while the notifier data
structure is still in use. Consider the following sequence:
CPU0 - mn_tree_inv_end() CPU1 - mmu_interval_notifier_remove()
----------------------------------- ------------------------------------
spin_lock(subscriptions->lock);
seq = subscriptions->invalidate_seq;
spin_lock(subscriptions->lock); spin_unlock(subscriptions->lock);
subscriptions->invalidate_seq++;
wait_event(invalidate_seq != seq);
return;
interval_tree_remove(interval_sub); kfree(interval_sub);
spin_unlock(subscriptions->lock);
wake_up_all();
As the wait_event() condition is true it will return immediately. This
can lead to use-after-free type errors if the caller frees the data
structure containing the interval notifier subscription while it is
still on a deferred list. Fix this by taking the appropriate lock when
reading invalidate_seq to ensure proper synchronisation.
I observed this whilst running stress testing during some development.
You do have to be pretty unlucky, but it leads to the usual problems of
use-after-free (memory corruption, kernel crash, difficult to diagnose
WARN_ON, etc).
Link: https://lkml.kernel.org/r/20220420043734.476348-1-apopple@nvidia.com
Fixes:
|
||
|
Nico Pache
|
ed5d4efb4d |
oom_kill.c: futex: delay the OOM reaper to allow time for proper futex cleanup
commit e4a38402c36e42df28eb1a5394be87e6571fb48a upstream.
The pthread struct is allocated on PRIVATE|ANONYMOUS memory [1] which
can be targeted by the oom reaper. This mapping is used to store the
futex robust list head; the kernel does not keep a copy of the robust
list and instead references a userspace address to maintain the
robustness during a process death.
A race can occur between exit_mm and the oom reaper that allows the oom
reaper to free the memory of the futex robust list before the exit path
has handled the futex death:
CPU1 CPU2
--------------------------------------------------------------------
page_fault
do_exit "signal"
wake_oom_reaper
oom_reaper
oom_reap_task_mm (invalidates mm)
exit_mm
exit_mm_release
futex_exit_release
futex_cleanup
exit_robust_list
get_user (EFAULT- can't access memory)
If the get_user EFAULT's, the kernel will be unable to recover the
waiters on the robust_list, leaving userspace mutexes hung indefinitely.
Delay the OOM reaper, allowing more time for the exit path to perform
the futex cleanup.
Reproducer: https://gitlab.com/jsavitz/oom_futex_reproducer
Based on a patch by Michal Hocko.
Link: https://elixir.bootlin.com/glibc/glibc-2.35/source/nptl/allocatestack.c#L370 [1]
Link: https://lkml.kernel.org/r/20220414144042.677008-1-npache@redhat.com
Fixes:
|
||
|
Christophe Leroy
|
6b932920b9 |
mm, hugetlb: allow for "high" userspace addresses
commit 5f24d5a579d1eace79d505b148808a850b417d4c upstream. This is a fix for commit |
||
|
Xiongwei Song
|
69848f9488 |
mm: page_alloc: fix building error on -Werror=array-compare
commit ca831f29f8f25c97182e726429b38c0802200c8f upstream.
Arthur Marsh reported we would hit the error below when building kernel
with gcc-12:
CC mm/page_alloc.o
mm/page_alloc.c: In function `mem_init_print_info':
mm/page_alloc.c:8173:27: error: comparison between two arrays [-Werror=array-compare]
8173 | if (start <= pos && pos < end && size > adj) \
|
In C++20, the comparision between arrays should be warned.
Link: https://lkml.kernel.org/r/20211125130928.32465-1-sxwjean@me.com
Signed-off-by: Xiongwei Song <sxwjean@gmail.com>
Reported-by: Arthur Marsh <arthur.marsh@internode.on.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
||
|
Patrick Wang
|
06c348fde5 |
mm: kmemleak: take a full lowmem check in kmemleak_*_phys()
commit 23c2d497de21f25898fbea70aeb292ab8acc8c94 upstream. The kmemleak_*_phys() apis do not check the address for lowmem's min boundary, while the caller may pass an address below lowmem, which will trigger an oops: # echo scan > /sys/kernel/debug/kmemleak Unable to handle kernel paging request at virtual address ff5fffffffe00000 Oops [#1] Modules linked in: CPU: 2 PID: 134 Comm: bash Not tainted 5.18.0-rc1-next-20220407 #33 Hardware name: riscv-virtio,qemu (DT) epc : scan_block+0x74/0x15c ra : scan_block+0x72/0x15c epc : ffffffff801e5806 ra : ffffffff801e5804 sp : ff200000104abc30 gp : ffffffff815cd4e8 tp : ff60000004cfa340 t0 : 0000000000000200 t1 : 00aaaaaac23954cc t2 : 00000000000003ff s0 : ff200000104abc90 s1 : ffffffff81b0ff28 a0 : 0000000000000000 a1 : ff5fffffffe01000 a2 : ffffffff81b0ff28 a3 : 0000000000000002 a4 : 0000000000000001 a5 : 0000000000000000 a6 : ff200000104abd7c a7 : 0000000000000005 s2 : ff5fffffffe00ff9 s3 : ffffffff815cd998 s4 : ffffffff815d0e90 s5 : ffffffff81b0ff28 s6 : 0000000000000020 s7 : ffffffff815d0eb0 s8 : ffffffffffffffff s9 : ff5fffffffe00000 s10: ff5fffffffe01000 s11: 0000000000000022 t3 : 00ffffffaa17db4c t4 : 000000000000000f t5 : 0000000000000001 t6 : 0000000000000000 status: 0000000000000100 badaddr: ff5fffffffe00000 cause: 000000000000000d scan_gray_list+0x12e/0x1a6 kmemleak_scan+0x2aa/0x57e kmemleak_write+0x32a/0x40c full_proxy_write+0x56/0x82 vfs_write+0xa6/0x2a6 ksys_write+0x6c/0xe2 sys_write+0x22/0x2a ret_from_syscall+0x0/0x2 The callers may not quite know the actual address they pass(e.g. from devicetree). So the kmemleak_*_phys() apis should guarantee the address they finally use is in lowmem range, so check the address for lowmem's min boundary. Link: https://lkml.kernel.org/r/20220413122925.33856-1-patrick.wang.shcn@gmail.com Signed-off-by: Patrick Wang <patrick.wang.shcn@gmail.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |