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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs fixes from Christian Brauner:
- Fix a regression caused by the anonymous inode rework. Making them
regular files causes various places in the kernel to tip over
starting with io_uring.
Revert to the former status quo and port our assertion to be based on
checking the inode so we don't lose the valuable VFS_*_ON_*()
assertions that have already helped discover weird behavior our
outright bugs.
- Fix the the upper bound calculation in fuse_fill_write_pages()
- Fix priority inversion issues in the eventpoll code
- Make secretmen use anon_inode_make_secure_inode() to avoid bypassing
the LSM layer
- Fix a netfs hang due to missing case in final DIO read result
collection
- Fix a double put of the netfs_io_request struct
- Provide some helpers to abstract out NETFS_RREQ_IN_PROGRESS flag
wrangling
- Fix infinite looping in netfs_wait_for_pause/request()
- Fix a netfs ref leak on an extra subrequest inserted into a request's
list of subreqs
- Fix various cifs RPC callbacks to set NETFS_SREQ_NEED_RETRY if a
subrequest fails retriably
- Fix a cifs warning in the workqueue code when reconnecting a channel
- Fix the updating of i_size in netfs to avoid a race between testing
if we should have extended the file with a DIO write and changing
i_size
- Merge the places in netfs that update i_size on write
- Fix coredump socket selftests
* tag 'vfs-6.16-rc5.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
anon_inode: rework assertions
netfs: Update tracepoints in a number of ways
netfs: Renumber the NETFS_RREQ_* flags to make traces easier to read
netfs: Merge i_size update functions
netfs: Fix i_size updating
smb: client: set missing retry flag in cifs_writev_callback()
smb: client: set missing retry flag in cifs_readv_callback()
smb: client: set missing retry flag in smb2_writev_callback()
netfs: Fix ref leak on inserted extra subreq in write retry
netfs: Fix looping in wait functions
netfs: Provide helpers to perform NETFS_RREQ_IN_PROGRESS flag wangling
netfs: Fix double put of request
netfs: Fix hang due to missing case in final DIO read result collection
eventpoll: Fix priority inversion problem
fuse: fix fuse_fill_write_pages() upper bound calculation
fs: export anon_inode_make_secure_inode() and fix secretmem LSM bypass
selftests/coredump: Fix "socket_detect_userspace_client" test failure
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memcg_path_store() assigns a newly allocated memory buffer to
filter->memcg_path, without deallocating the previously allocated and
assigned memory buffer. As a result, users can leak kernel memory by
continuously writing a data to memcg_path DAMOS sysfs file. Fix the leak
by deallocating the previously set memory buffer.
Link: https://lkml.kernel.org/r/20250619183608.6647-2-sj@kernel.org
Fixes: 7ee161f18b5d ("mm/damon/sysfs-schemes: implement filter directory")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org> [6.3.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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percpu variable tag->counters
When loading a module, as long as the module has memory allocation
operations, kmemleak produces a false positive report that resembles the
following:
unreferenced object (percpu) 0x7dfd232a1650 (size 16):
comm "modprobe", pid 1301, jiffies 4294940249
hex dump (first 16 bytes on cpu 2):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace (crc 0):
kmemleak_alloc_percpu+0xb4/0xd0
pcpu_alloc_noprof+0x700/0x1098
load_module+0xd4/0x348
codetag_module_init+0x20c/0x450
codetag_load_module+0x70/0xb8
load_module+0xef8/0x1608
init_module_from_file+0xec/0x158
idempotent_init_module+0x354/0x608
__arm64_sys_finit_module+0xbc/0x150
invoke_syscall+0xd4/0x258
el0_svc_common.constprop.0+0xb4/0x240
do_el0_svc+0x48/0x68
el0_svc+0x40/0xf8
el0t_64_sync_handler+0x10c/0x138
el0t_64_sync+0x1ac/0x1b0
This is because the module can only indirectly reference
alloc_tag_counters through the alloc_tag section, which misleads kmemleak.
However, we don't have a kmemleak ignore interface for percpu allocations
yet. So let's create one and invoke it for tag->counters.
[gehao@kylinos.cn: fix build error when CONFIG_DEBUG_KMEMLEAK=n, s/igonore/ignore/]
Link: https://lkml.kernel.org/r/20250620093102.2416767-1-hao.ge@linux.dev
Link: https://lkml.kernel.org/r/20250619183154.2122608-1-hao.ge@linux.dev
Fixes: 12ca42c23775 ("alloc_tag: allocate percpu counters for module tags dynamically")
Signed-off-by: Hao Ge <gehao@kylinos.cn>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Suren Baghdasaryan <surenb@google.com> [lib/alloc_tag.c]
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In isolate_or_dissolve_huge_folio(), after acquiring the hugetlb_lock, it
is only for the purpose of obtaining the correct hstate, which is then
passed to alloc_and_dissolve_hugetlb_folio().
alloc_and_dissolve_hugetlb_folio() itself also acquires the hugetlb_lock.
We can have alloc_and_dissolve_hugetlb_folio() obtain the hstate by
itself, so that isolate_or_dissolve_huge_folio() no longer needs to
acquire the hugetlb_lock. In addition, we keep the folio_test_hugetlb()
check within isolate_or_dissolve_huge_folio(). By doing so, we can avoid
disrupting the normal path by vainly holding the hugetlb_lock.
replace_free_hugepage_folios() has the same issue, and we should address
it as well.
Addresses a possible performance problem which was added by the hotfix
113ed54ad276 ("mm/hugetlb: fix kernel NULL pointer dereference when
replacing free hugetlb folios").
Link: https://lkml.kernel.org/r/1748317010-16272-1-git-send-email-yangge1116@126.com
Fixes: 113ed54ad276 ("mm/hugetlb: fix kernel NULL pointer dereference when replacing free hugetlb folios")
Signed-off-by: Ge Yang <yangge1116@126.com>
Suggested-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <21cnbao@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
"20 hotfixes. 7 are cc:stable and the remainder address post-6.15
issues or aren't considered necessary for -stable kernels. Only 4 are
for MM.
- The series `Revert "bcache: update min_heap_callbacks to use
default builtin swap"' from Kuan-Wei Chiu backs out the author's
recent min_heap changes due to a performance regression.
A fix for this regression has been developed but we felt it best to
go back to the known-good version to give the new code more bake
time.
- A lot of MAINTAINERS maintenance.
I like to get these changes upstreamed promptly because they can't
break things and more accurate/complete MAINTAINERS info hopefully
improves the speed and accuracy of our responses to submitters and
reporters"
* tag 'mm-hotfixes-stable-2025-06-22-18-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
MAINTAINERS: add additional mmap-related files to mmap section
MAINTAINERS: add memfd, shmem quota files to shmem section
MAINTAINERS: add stray rmap file to mm rmap section
MAINTAINERS: add hugetlb_cgroup.c to hugetlb section
MAINTAINERS: add further init files to mm init block
MAINTAINERS: update maintainers for HugeTLB
maple_tree: fix MA_STATE_PREALLOC flag in mas_preallocate()
MAINTAINERS: add missing test files to mm gup section
MAINTAINERS: add missing mm/workingset.c file to mm reclaim section
selftests/mm: skip uprobe vma merge test if uprobes are not enabled
bcache: remove unnecessary select MIN_HEAP
Revert "bcache: remove heap-related macros and switch to generic min_heap"
Revert "bcache: update min_heap_callbacks to use default builtin swap"
selftests/mm: add configs to fix testcase failure
kho: initialize tail pages for higher order folios properly
MAINTAINERS: add linux-mm@ list to Kexec Handover
mm: userfaultfd: fix race of userfaultfd_move and swap cache
mm/gup: revert "mm: gup: fix infinite loop within __get_longterm_locked"
selftests/mm: increase timeout from 180 to 900 seconds
mm/shmem, swap: fix softlockup with mTHP swapin
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Export anon_inode_make_secure_inode() to allow KVM guest_memfd to create
anonymous inodes with proper security context. This replaces the current
pattern of calling alloc_anon_inode() followed by
inode_init_security_anon() for creating security context manually.
This change also fixes a security regression in secretmem where the
S_PRIVATE flag was not cleared after alloc_anon_inode(), causing
LSM/SELinux checks to be bypassed for secretmem file descriptors.
As guest_memfd currently resides in the KVM module, we need to export this
symbol for use outside the core kernel. In the future, guest_memfd might be
moved to core-mm, at which point the symbols no longer would have to be
exported. When/if that happens is still unclear.
Fixes: 2bfe15c52612 ("mm: create security context for memfd_secret inodes")
Suggested-by: David Hildenbrand <david@redhat.com>
Suggested-by: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Shivank Garg <shivankg@amd.com>
Link: https://lore.kernel.org/20250620070328.803704-3-shivankg@amd.com
Acked-by: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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This commit fixes two kinds of races, they may have different results:
Barry reported a BUG_ON in commit c50f8e6053b0, we may see the same
BUG_ON if the filemap lookup returned NULL and folio is added to swap
cache after that.
If another kind of race is triggered (folio changed after lookup) we
may see RSS counter is corrupted:
[ 406.893936] BUG: Bad rss-counter state mm:ffff0000c5a9ddc0
type:MM_ANONPAGES val:-1
[ 406.894071] BUG: Bad rss-counter state mm:ffff0000c5a9ddc0
type:MM_SHMEMPAGES val:1
Because the folio is being accounted to the wrong VMA.
I'm not sure if there will be any data corruption though, seems no.
The issues above are critical already.
On seeing a swap entry PTE, userfaultfd_move does a lockless swap cache
lookup, and tries to move the found folio to the faulting vma. Currently,
it relies on checking the PTE value to ensure that the moved folio still
belongs to the src swap entry and that no new folio has been added to the
swap cache, which turns out to be unreliable.
While working and reviewing the swap table series with Barry, following
existing races are observed and reproduced [1]:
In the example below, move_pages_pte is moving src_pte to dst_pte, where
src_pte is a swap entry PTE holding swap entry S1, and S1 is not in the
swap cache:
CPU1 CPU2
userfaultfd_move
move_pages_pte()
entry = pte_to_swp_entry(orig_src_pte);
// Here it got entry = S1
... < interrupted> ...
<swapin src_pte, alloc and use folio A>
// folio A is a new allocated folio
// and get installed into src_pte
<frees swap entry S1>
// src_pte now points to folio A, S1
// has swap count == 0, it can be freed
// by folio_swap_swap or swap
// allocator's reclaim.
<try to swap out another folio B>
// folio B is a folio in another VMA.
<put folio B to swap cache using S1 >
// S1 is freed, folio B can use it
// for swap out with no problem.
...
folio = filemap_get_folio(S1)
// Got folio B here !!!
... < interrupted again> ...
<swapin folio B and free S1>
// Now S1 is free to be used again.
<swapout src_pte & folio A using S1>
// Now src_pte is a swap entry PTE
// holding S1 again.
folio_trylock(folio)
move_swap_pte
double_pt_lock
is_pte_pages_stable
// Check passed because src_pte == S1
folio_move_anon_rmap(...)
// Moved invalid folio B here !!!
The race window is very short and requires multiple collisions of multiple
rare events, so it's very unlikely to happen, but with a deliberately
constructed reproducer and increased time window, it can be reproduced
easily.
This can be fixed by checking if the folio returned by filemap is the
valid swap cache folio after acquiring the folio lock.
Another similar race is possible: filemap_get_folio may return NULL, but
folio (A) could be swapped in and then swapped out again using the same
swap entry after the lookup. In such a case, folio (A) may remain in the
swap cache, so it must be moved too:
CPU1 CPU2
userfaultfd_move
move_pages_pte()
entry = pte_to_swp_entry(orig_src_pte);
// Here it got entry = S1, and S1 is not in swap cache
folio = filemap_get_folio(S1)
// Got NULL
... < interrupted again> ...
<swapin folio A and free S1>
<swapout folio A re-using S1>
move_swap_pte
double_pt_lock
is_pte_pages_stable
// Check passed because src_pte == S1
folio_move_anon_rmap(...)
// folio A is ignored !!!
Fix this by checking the swap cache again after acquiring the src_pte
lock. And to avoid the filemap overhead, we check swap_map directly [2].
The SWP_SYNCHRONOUS_IO path does make the problem more complex, but so far
we don't need to worry about that, since folios can only be exposed to the
swap cache in the swap out path, and this is covered in this patch by
checking the swap cache again after acquiring the src_pte lock.
Testing with a simple C program that allocates and moves several GB of
memory did not show any observable performance change.
Link: https://lkml.kernel.org/r/20250604151038.21968-1-ryncsn@gmail.com
Fixes: adef440691ba ("userfaultfd: UFFDIO_MOVE uABI")
Signed-off-by: Kairui Song <kasong@tencent.com>
Closes: https://lore.kernel.org/linux-mm/CAMgjq7B1K=6OOrK2OUZ0-tqCzi+EJt+2_K97TPGoSt=9+JwP7Q@mail.gmail.com/ [1]
Link: https://lore.kernel.org/all/CAGsJ_4yJhJBo16XhiC-nUzSheyX-V3-nFE+tAi=8Y560K8eT=A@mail.gmail.com/ [2]
Reviewed-by: Lokesh Gidra <lokeshgidra@google.com>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Barry Song <baohua@kernel.org>
Reviewed-by: Chris Li <chrisl@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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After commit 1aaf8c122918 ("mm: gup: fix infinite loop within
__get_longterm_locked") we are able to longterm pin folios that are not
supposed to get longterm pinned, simply because they temporarily have the
LRU flag cleared (esp. temporarily isolated).
For example, two __get_longterm_locked() callers can race, or
__get_longterm_locked() can race with anything else that temporarily
isolates folios.
The introducing commit mentions the use case of a driver that uses
vm_ops->fault to insert pages allocated through cma_alloc() into the page
tables, assuming they can later get longterm pinned. These pages/ folios
would never have the LRU flag set and consequently cannot get isolated.
There is no known in-tree user making use of that so far, fortunately.
To handle that in the future -- and avoid retrying forever to
isolate/migrate them -- we will need a different mechanism for the CMA
area *owner* to indicate that it actually already allocated the page and
is fine with longterm pinning it. The LRU flag is not suitable for that.
Probably we can lookup the relevant CMA area and query the bitmap; we only
have have to care about some races, probably. If already allocated, we
could just allow longterm pinning)
Anyhow, let's fix the "must not be longterm pinned" problem first by
reverting the original commit.
Link: https://lkml.kernel.org/r/20250611131314.594529-1-david@redhat.com
Fixes: 1aaf8c122918 ("mm: gup: fix infinite loop within __get_longterm_locked")
Signed-off-by: David Hildenbrand <david@redhat.com>
Closes: https://lore.kernel.org/all/20250522092755.GA3277597@tiffany/
Reported-by: Hyesoo Yu <hyesoo.yu@samsung.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Peter Xu <peterx@redhat.com>
Cc: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Cc: Aijun Sun <aijun.sun@unisoc.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Following softlockup can be easily reproduced on my test machine with:
echo always > /sys/kernel/mm/transparent_hugepage/hugepages-64kB/enabled
swapon /dev/zram0 # zram0 is a 48G swap device
mkdir -p /sys/fs/cgroup/memory/test
echo 1G > /sys/fs/cgroup/test/memory.max
echo $BASHPID > /sys/fs/cgroup/test/cgroup.procs
while true; do
dd if=/dev/zero of=/tmp/test.img bs=1M count=5120
cat /tmp/test.img > /dev/null
rm /tmp/test.img
done
Then after a while:
watchdog: BUG: soft lockup - CPU#0 stuck for 763s! [cat:5787]
Modules linked in: zram virtiofs
CPU: 0 UID: 0 PID: 5787 Comm: cat Kdump: loaded Tainted: G L 6.15.0.orig-gf3021d9246bc-dirty #118 PREEMPT(voluntary)·
Tainted: [L]=SOFTLOCKUP
Hardware name: Red Hat KVM/RHEL-AV, BIOS 0.0.0 02/06/2015
RIP: 0010:mpol_shared_policy_lookup+0xd/0x70
Code: e9 b8 b4 ff ff 31 c0 c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 0f 1f 44 00 00 41 54 55 53 <48> 8b 1f 48 85 db 74 41 4c 8d 67 08 48 89 fb 48 89 f5 4c 89 e7 e8
RSP: 0018:ffffc90002b1fc28 EFLAGS: 00000202
RAX: 00000000001c20ca RBX: 0000000000724e1e RCX: 0000000000000001
RDX: ffff888118e214c8 RSI: 0000000000057d42 RDI: ffff888118e21518
RBP: 000000000002bec8 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000bf4 R11: 0000000000000000 R12: 0000000000000001
R13: 00000000001c20ca R14: 00000000001c20ca R15: 0000000000000000
FS: 00007f03f995c740(0000) GS:ffff88a07ad9a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f03f98f1000 CR3: 0000000144626004 CR4: 0000000000770eb0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
shmem_alloc_folio+0x31/0xc0
shmem_swapin_folio+0x309/0xcf0
? filemap_get_entry+0x117/0x1e0
? xas_load+0xd/0xb0
? filemap_get_entry+0x101/0x1e0
shmem_get_folio_gfp+0x2ed/0x5b0
shmem_file_read_iter+0x7f/0x2e0
vfs_read+0x252/0x330
ksys_read+0x68/0xf0
do_syscall_64+0x4c/0x1c0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f03f9a46991
Code: 00 48 8b 15 81 14 10 00 f7 d8 64 89 02 b8 ff ff ff ff eb bd e8 20 ad 01 00 f3 0f 1e fa 80 3d 35 97 10 00 00 74 13 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 4f c3 66 0f 1f 44 00 00 55 48 89 e5 48 83 ec
RSP: 002b:00007fff3c52bd28 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000040000 RCX: 00007f03f9a46991
RDX: 0000000000040000 RSI: 00007f03f98ba000 RDI: 0000000000000003
RBP: 00007fff3c52bd50 R08: 0000000000000000 R09: 00007f03f9b9a380
R10: 0000000000000022 R11: 0000000000000246 R12: 0000000000040000
R13: 00007f03f98ba000 R14: 0000000000000003 R15: 0000000000000000
</TASK>
The reason is simple, readahead brought some order 0 folio in swap cache,
and the swapin mTHP folio being allocated is in conflict with it, so
swapcache_prepare fails and causes shmem_swap_alloc_folio to return
-EEXIST, and shmem simply retries again and again causing this loop.
Fix it by applying a similar fix for anon mTHP swapin.
The performance change is very slight, time of swapin 10g zero folios
with shmem (test for 12 times):
Before: 2.47s
After: 2.48s
[kasong@tencent.com: add comment]
Link: https://lkml.kernel.org/r/20250610181645.45922-1-ryncsn@gmail.com
Link: https://lkml.kernel.org/r/20250610181645.45922-1-ryncsn@gmail.com
Link: https://lkml.kernel.org/r/20250609171751.36305-1-ryncsn@gmail.com
Fixes: 1dd44c0af4fa ("mm: shmem: skip swapcache for swapin of synchronous swap device")
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: Barry Song <baohua@kernel.org>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Dave Hansen:
"This is a pretty scattered set of fixes. The majority of them are
further fixups around the recent ITS mitigations.
The rest don't really have a coherent story:
- Some flavors of Xen PV guests don't support large pages, but the
set_memory.c code assumes all CPUs support them.
Avoid problems with a quick CPU feature check.
- The TDX code has some wrappers to help retry calls to the TDX
module. They use function pointers to assembly functions and the
compiler usually generates direct CALLs. But some new compilers,
plus -Os turned them in to indirect CALLs and the assembly code was
not annotated for indirect calls.
Force inlining of the helper to fix it up.
- Last, a FRED issue showed up when single-stepping. It's fine when
using an external debugger, but was getting stuck returning from a
SIGTRAP handler otherwise.
Clear the FRED 'swevent' bit to ensure that forward progress is
made"
* tag 'x86_urgent_for_6.16-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Revert "mm/execmem: Unify early execmem_cache behaviour"
x86/its: explicitly manage permissions for ITS pages
x86/its: move its_pages array to struct mod_arch_specific
x86/Kconfig: only enable ROX cache in execmem when STRICT_MODULE_RWX is set
x86/mm/pat: don't collapse pages without PSE set
x86/virt/tdx: Avoid indirect calls to TDX assembly functions
selftests/x86: Add a test to detect infinite SIGTRAP handler loop
x86/fred/signal: Prevent immediate repeat of single step trap on return from SIGTRAP handler
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
"9 hotfixes. 3 are cc:stable and the remainder address post-6.15 issues
or aren't considered necessary for -stable kernels. Only 4 are for MM"
* tag 'mm-hotfixes-stable-2025-06-13-21-56' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
mm: add mmap_prepare() compatibility layer for nested file systems
init: fix build warnings about export.h
MAINTAINERS: add Barry as a THP reviewer
drivers/rapidio/rio_cm.c: prevent possible heap overwrite
mm: close theoretical race where stale TLB entries could linger
mm/vma: reset VMA iterator on commit_merge() OOM failure
docs: proc: update VmFlags documentation in smaps
scatterlist: fix extraneous '@'-sign kernel-doc notation
selftests/mm: skip failed memfd setups in gup_longterm
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Nested file systems, that is those which invoke call_mmap() within their
own f_op->mmap() handlers, may encounter underlying file systems which
provide the f_op->mmap_prepare() hook introduced by commit c84bf6dd2b83
("mm: introduce new .mmap_prepare() file callback").
We have a chicken-and-egg scenario here - until all file systems are
converted to using .mmap_prepare(), we cannot convert these nested
handlers, as we can't call f_op->mmap from an .mmap_prepare() hook.
So we have to do it the other way round - invoke the .mmap_prepare() hook
from an .mmap() one.
in order to do so, we need to convert VMA state into a struct vm_area_desc
descriptor, invoking the underlying file system's f_op->mmap_prepare()
callback passing a pointer to this, and then setting VMA state accordingly
and safely.
This patch achieves this via the compat_vma_mmap_prepare() function, which
we invoke from call_mmap() if f_op->mmap_prepare() is specified in the
passed in file pointer.
We place the fundamental logic into mm/vma.h where VMA manipulation
belongs. We also update the VMA userland tests to accommodate the
changes.
The compat_vma_mmap_prepare() function and its associated machinery is
temporary, and will be removed once the conversion of file systems is
complete.
We carefully place this code so it can be used with CONFIG_MMU and also
with cutting edge nommu silicon.
[akpm@linux-foundation.org: export compat_vma_mmap_prepare tp fix build]
[lorenzo.stoakes@oracle.com: remove unused declarations]
Link: https://lkml.kernel.org/r/ac3ae324-4c65-432a-8c6d-2af988b18ac8@lucifer.local
Link: https://lkml.kernel.org/r/20250609165749.344976-1-lorenzo.stoakes@oracle.com
Fixes: c84bf6dd2b83 ("mm: introduce new .mmap_prepare() file callback").
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reported-by: Jann Horn <jannh@google.com>
Closes: https://lore.kernel.org/linux-mm/CAG48ez04yOEVx1ekzOChARDDBZzAKwet8PEoPM4Ln3_rk91AzQ@mail.gmail.com/
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Commit 3ea277194daa ("mm, mprotect: flush TLB if potentially racing with a
parallel reclaim leaving stale TLB entries") described a theoretical race
as such:
"""
Nadav Amit identified a theoretical race between page reclaim and mprotect
due to TLB flushes being batched outside of the PTL being held.
He described the race as follows:
CPU0 CPU1
---- ----
user accesses memory using RW PTE
[PTE now cached in TLB]
try_to_unmap_one()
==> ptep_get_and_clear()
==> set_tlb_ubc_flush_pending()
mprotect(addr, PROT_READ)
==> change_pte_range()
==> [ PTE non-present - no flush ]
user writes using cached RW PTE
...
try_to_unmap_flush()
The same type of race exists for reads when protecting for PROT_NONE and
also exists for operations that can leave an old TLB entry behind such as
munmap, mremap and madvise.
"""
The solution was to introduce flush_tlb_batched_pending() and call it
under the PTL from mprotect/madvise/munmap/mremap to complete any pending
tlb flushes.
However, while madvise_free_pte_range() and
madvise_cold_or_pageout_pte_range() were both retro-fitted to call
flush_tlb_batched_pending() immediately after initially acquiring the PTL,
they both temporarily release the PTL to split a large folio if they
stumble upon one. In this case, where re-acquiring the PTL
flush_tlb_batched_pending() must be called again, but it previously was
not. Let's fix that.
There are 2 Fixes: tags here: the first is the commit that fixed
madvise_free_pte_range(). The second is the commit that added
madvise_cold_or_pageout_pte_range(), which looks like it copy/pasted the
faulty pattern from madvise_free_pte_range().
This is a theoretical bug discovered during code review.
Link: https://lkml.kernel.org/r/20250606092809.4194056-1-ryan.roberts@arm.com
Fixes: 3ea277194daa ("mm, mprotect: flush TLB if potentially racing with a parallel reclaim leaving stale TLB entries")
Fixes: 9c276cc65a58 ("mm: introduce MADV_COLD")
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Jann Horn <jannh@google.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mel Gorman <mgorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
While an OOM failure in commit_merge() isn't really feasible due to the
allocation which might fail (a maple tree pre-allocation) being 'too small
to fail', we do need to handle this case correctly regardless.
In vma_merge_existing_range(), we can theoretically encounter failures
which result in an OOM error in two ways - firstly dup_anon_vma() might
fail with an OOM error, and secondly commit_merge() failing, ultimately,
to pre-allocate a maple tree node.
The abort logic for dup_anon_vma() resets the VMA iterator to the initial
range, ensuring that any logic looping on this iterator will correctly
proceed to the next VMA.
However the commit_merge() abort logic does not do the same thing. This
resulted in a syzbot report occurring because mlockall() iterates through
VMAs, is tolerant of errors, but ended up with an incorrect previous VMA
being specified due to incorrect iterator state.
While making this change, it became apparent we are duplicating logic -
the logic introduced in commit 41e6ddcaa0f1 ("mm/vma: add give_up_on_oom
option on modify/merge, use in uffd release") duplicates the
vmg->give_up_on_oom check in both abort branches.
Additionally, we observe that we can perform the anon_dup check safely on
dup_anon_vma() failure, as this will not be modified should this call
fail.
Finally, we need to reset the iterator in both cases, so now we can simply
use the exact same code to abort for both.
We remove the VM_WARN_ON(err != -ENOMEM) as it would be silly for this to
be otherwise and it allows us to implement the abort check more neatly.
Link: https://lkml.kernel.org/r/20250606125032.164249-1-lorenzo.stoakes@oracle.com
Fixes: 47b16d0462a4 ("mm: abort vma_modify() on merge out of memory failure")
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reported-by: syzbot+d16409ea9ecc16ed261a@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-mm/6842cc67.a00a0220.29ac89.003b.GAE@google.com/
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Jann Horn <jannh@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The commit d6d1e3e6580c ("mm/execmem: Unify early execmem_cache
behaviour") changed early behaviour of execemem ROX cache to allow its
usage in early x86 code that allocates text pages when
CONFIG_MITGATION_ITS is enabled.
The permission management of the pages allocated from execmem for ITS
mitigation is now completely contained in arch/x86/kernel/alternatives.c
and therefore there is no need to special case early allocations in
execmem.
This reverts commit d6d1e3e6580ca35071ad474381f053cbf1fb6414.
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20250603111446.2609381-6-rppt@kernel.org
|
|
This reverts commit 28615e6eed152f2fda5486680090b74aeed7b554.
No, we don't make random features default to being on.
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: SeongJae Park <sj@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Move this API to the canonical timer_*() namespace.
[ tglx: Redone against pre rc1 ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/aB2X0jCKQO56WdMt@gmail.com
|
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git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
Pull LoongArch updates from Huacai Chen:
- Adjust the 'make install' operation
- Support SCHED_MC (Multi-core scheduler)
- Enable ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS
- Enable HAVE_ARCH_STACKLEAK
- Increase max supported CPUs up to 2048
- Introduce the numa_memblks conversion
- Add PWM controller nodes in dts
- Some bug fixes and other small changes
* tag 'loongarch-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson:
platform/loongarch: laptop: Unregister generic_sub_drivers on exit
platform/loongarch: laptop: Add backlight power control support
platform/loongarch: laptop: Get brightness setting from EC on probe
LoongArch: dts: Add PWM support to Loongson-2K2000
LoongArch: dts: Add PWM support to Loongson-2K1000
LoongArch: dts: Add PWM support to Loongson-2K0500
LoongArch: vDSO: Correctly use asm parameters in syscall wrappers
LoongArch: Fix panic caused by NULL-PMD in huge_pte_offset()
LoongArch: Preserve firmware configuration when desired
LoongArch: Avoid using $r0/$r1 as "mask" for csrxchg
LoongArch: Introduce the numa_memblks conversion
LoongArch: Increase max supported CPUs up to 2048
LoongArch: Enable HAVE_ARCH_STACKLEAK
LoongArch: Enable ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS
LoongArch: Add SCHED_MC (Multi-core scheduler) support
LoongArch: Add some annotations in archhelp
LoongArch: Using generic scripts/install.sh in `make install`
LoongArch: Add a default install.sh
|
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull more MM updates from Andrew Morton:
"The series 'Fix uprobe pte be overwritten when expanding vma' fixes a
longstanding and quite obscure bug related to the vma merging of the
uprobe mmap page"
* tag 'mm-stable-2025-06-06-16-09' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
selftests/mm: add test about uprobe pte be orphan during vma merge
selftests/mm: extract read_sysfs and write_sysfs into vm_util
mm: expose abnormal new_pte during move_ptes
mm: fix uprobe pte be overwritten when expanding vma
mm/damon: s/primitives/code/ on comments
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
"13 hotfixes.
6 are cc:stable and the remainder address post-6.15 issues or aren't
considered necessary for -stable kernels. 11 are for MM"
* tag 'mm-hotfixes-stable-2025-06-06-16-02' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
kernel/rcu/tree_stall: add /sys/kernel/rcu_stall_count
MAINTAINERS: add mm swap section
kmsan: test: add module description
MAINTAINERS: add tlb trace events to MMU GATHER AND TLB INVALIDATION
mm/hugetlb: fix huge_pmd_unshare() vs GUP-fast race
mm/hugetlb: unshare page tables during VMA split, not before
MAINTAINERS: add Alistair as reviewer of mm memory policy
iov_iter: use iov_offset for length calculation in iov_iter_aligned_bvec
mm/mempolicy: fix incorrect freeing of wi_kobj
alloc_tag: handle module codetag load errors as module load failures
mm/madvise: handle madvise_lock() failure during race unwinding
mm: fix vmstat after removing NR_BOUNCE
KVM: s390: rename PROT_NONE to PROT_TYPE_DUMMY
|
|
Every module should have a description, and kbuild now warns for those
that don't.
WARNING: modpost: missing MODULE_DESCRIPTION() in mm/kmsan/kmsan_test.o
Link: https://lkml.kernel.org/r/20250603075323.1839608-1-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Macro Elver <elver@google.com>
Cc: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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huge_pmd_unshare() drops a reference on a page table that may have
previously been shared across processes, potentially turning it into a
normal page table used in another process in which unrelated VMAs can
afterwards be installed.
If this happens in the middle of a concurrent gup_fast(), gup_fast() could
end up walking the page tables of another process. While I don't see any
way in which that immediately leads to kernel memory corruption, it is
really weird and unexpected.
Fix it with an explicit broadcast IPI through tlb_remove_table_sync_one(),
just like we do in khugepaged when removing page tables for a THP
collapse.
Link: https://lkml.kernel.org/r/20250528-hugetlb-fixes-splitrace-v2-2-1329349bad1a@google.com
Link: https://lkml.kernel.org/r/20250527-hugetlb-fixes-splitrace-v1-2-f4136f5ec58a@google.com
Fixes: 39dde65c9940 ("[PATCH] shared page table for hugetlb page")
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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Currently, __split_vma() triggers hugetlb page table unsharing through
vm_ops->may_split(). This happens before the VMA lock and rmap locks are
taken - which is too early, it allows racing VMA-locked page faults in our
process and racing rmap walks from other processes to cause page tables to
be shared again before we actually perform the split.
Fix it by explicitly calling into the hugetlb unshare logic from
__split_vma() in the same place where THP splitting also happens. At that
point, both the VMA and the rmap(s) are write-locked.
An annoying detail is that we can now call into the helper
hugetlb_unshare_pmds() from two different locking contexts:
1. from hugetlb_split(), holding:
- mmap lock (exclusively)
- VMA lock
- file rmap lock (exclusively)
2. hugetlb_unshare_all_pmds(), which I think is designed to be able to
call us with only the mmap lock held (in shared mode), but currently
only runs while holding mmap lock (exclusively) and VMA lock
Backporting note:
This commit fixes a racy protection that was introduced in commit
b30c14cd6102 ("hugetlb: unshare some PMDs when splitting VMAs"); that
commit claimed to fix an issue introduced in 5.13, but it should actually
also go all the way back.
[jannh@google.com: v2]
Link: https://lkml.kernel.org/r/20250528-hugetlb-fixes-splitrace-v2-1-1329349bad1a@google.com
Link: https://lkml.kernel.org/r/20250528-hugetlb-fixes-splitrace-v2-0-1329349bad1a@google.com
Link: https://lkml.kernel.org/r/20250527-hugetlb-fixes-splitrace-v1-1-f4136f5ec58a@google.com
Fixes: 39dde65c9940 ("[PATCH] shared page table for hugetlb page")
Signed-off-by: Jann Horn <jannh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org> [b30c14cd6102: hugetlb: unshare some PMDs when splitting VMAs]
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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We should not free wi_group->wi_kobj here. In the error path of
add_weighted_interleave_group() where this snippet is called from,
kobj_{del, put} is immediately called right after this section. Thus, it
is not only unnecessary but also incorrect to free it here.
Link: https://lkml.kernel.org/r/20250602162345.2595696-1-joshua.hahnjy@gmail.com
Fixes: e341f9c3c841 ("mm/mempolicy: Weighted Interleave Auto-tuning")
Signed-off-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202506011545.Fduxqxqj-lkp@intel.com/
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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When unwinding race on -ERESTARTNOINTR handling of process_madvise(),
madvise_lock() failure is ignored. Check the failure and abort remaining
works in the case.
Link: https://lkml.kernel.org/r/20250602174926.1074-1-sj@kernel.org
Fixes: 4000e3d0a367 ("mm/madvise: remove redundant mmap_lock operations from process_madvise()")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Barry Song <21cnbao@gmail.com>
Closes: https://lore.kernel.org/CAGsJ_4xJXXO0G+4BizhohSZ4yDteziPw43_uF8nPXPWxUVChzw@mail.gmail.com
Reviewed-by: Jann Horn <jannh@google.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Barry Song <baohua@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Hongyu noticed that the nr_unaccepted counter kept growing even in the
absence of unaccepted memory on the machine.
This happens due to a commit that removed NR_BOUNCE: it removed the
counter from the enum zone_stat_item, but left it in the vmstat_text
array.
As a result, all counters below nr_bounce in /proc/vmstat are shifted by
one line, causing the numa_hit counter to be labeled as nr_unaccepted.
To fix this issue, remove nr_bounce from the vmstat_text array.
Link: https://lkml.kernel.org/r/20250529103832.2937460-1-kirill.shutemov@linux.intel.com
Fixes: 194df9f66db8 ("mm: remove NR_BOUNCE zone stat")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Hongyu Ning <hongyu.ning@linux.intel.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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When executing move_ptes, the new_pte must be NULL, otherwise it will be
overwritten by the old_pte, and cause the abnormal new_pte to be leaked.
In order to make this problem to be more explicit, let's add WARN_ON_ONCE
when new_pte is not NULL.
[akpm@linux-foundation.org: s/WARN_ON_ONCE/VM_WARN_ON_ONCE/]
Link: https://lkml.kernel.org/r/20250529155650.4017699-3-pulehui@huaweicloud.com
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Jann Horn <jannh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "Fix uprobe pte be overwritten when expanding vma".
This patch (of 4):
We encountered a BUG alert triggered by Syzkaller as follows:
BUG: Bad rss-counter state mm:00000000b4a60fca type:MM_ANONPAGES val:1
And we can reproduce it with the following steps:
1. register uprobe on file at zero offset
2. mmap the file at zero offset:
addr1 = mmap(NULL, 2 * 4096, PROT_NONE, MAP_PRIVATE, fd, 0);
3. mremap part of vma1 to new vma2:
addr2 = mremap(addr1, 4096, 2 * 4096, MREMAP_MAYMOVE);
4. mremap back to orig addr1:
mremap(addr2, 4096, 4096, MREMAP_MAYMOVE | MREMAP_FIXED, addr1);
In step 3, the vma1 range [addr1, addr1 + 4096] will be remap to new vma2
with range [addr2, addr2 + 8192], and remap uprobe anon page from the vma1
to vma2, then unmap the vma1 range [addr1, addr1 + 4096].
In step 4, the vma2 range [addr2, addr2 + 4096] will be remap back to the
addr range [addr1, addr1 + 4096]. Since the addr range [addr1 + 4096,
addr1 + 8192] still maps the file, it will take vma_merge_new_range to
expand the range, and then do uprobe_mmap in vma_complete. Since the
merged vma pgoff is also zero offset, it will install uprobe anon page to
the merged vma. However, the upcomming move_page_tables step, which use
set_pte_at to remap the vma2 uprobe pte to the merged vma, will overwrite
the newly uprobe pte in the merged vma, and lead that pte to be orphan.
Since the uprobe pte will be remapped to the merged vma, we can remove the
unnecessary uprobe_mmap upon merged vma.
This problem was first found in linux-6.6.y and also exists in the
community syzkaller:
https://lore.kernel.org/all/000000000000ada39605a5e71711@google.com/T/
Link: https://lkml.kernel.org/r/20250529155650.4017699-1-pulehui@huaweicloud.com
Link: https://lkml.kernel.org/r/20250529155650.4017699-2-pulehui@huaweicloud.com
Fixes: 2b1444983508 ("uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints")
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Suggested-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The word 'primitive' is not explicit. To make the code more easily
understood, this commit renames 'primitives' to 'code' in header comments
of some source files.
Link: https://lkml.kernel.org/r/20250530053115.153238-1-lienze@kylinos.cn
Signed-off-by: Enze Li <lienze@kylinos.cn>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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|
git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab
Pull slab updates from Vlastimil Babka:
- Make kvmalloc() more suitable for callers that need it to succeed,
but without unnecessary overhead by reclaim and compaction to get a
physically contiguous allocation.
Instead fall back to vmalloc() more easily by default, unless
instructed by __GFP_RETRY_MAYFAIL to prefer kmalloc() harder. This
should allow the removal of a xfs-specific workaround (Michal Hocko)
- Remove potentially excessive warnings due to memory pressure when
allocating structures for per-object allocation profiling metadata
(Usama Arif)
* tag 'slab-for-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
mm: slub: only warn once when allocating slab obj extensions fails
mm: kvmalloc: make kmalloc fast path real fast path
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull more MM updates from Andrew Morton:
- "zram: support algorithm-specific parameters" from Sergey Senozhatsky
adds infrastructure for passing algorithm-specific parameters into
zram. A single parameter `winbits' is implemented at this time.
- "memcg: nmi-safe kmem charging" from Shakeel Butt makes memcg
charging nmi-safe, which is required by BFP, which can operate in NMI
context.
- "Some random fixes and cleanup to shmem" from Kemeng Shi implements
small fixes and cleanups in the shmem code.
- "Skip mm selftests instead when kernel features are not present" from
Zi Yan fixes some issues in the MM selftest code.
- "mm/damon: build-enable essential DAMON components by default" from
SeongJae Park reworks DAMON Kconfig to make it easier to enable
CONFIG_DAMON.
- "sched/numa: add statistics of numa balance task migration" from Libo
Chen adds more info into sysfs and procfs files to improve visibility
into the NUMA balancer's task migration activity.
- "selftests/mm: cow and gup_longterm cleanups" from Mark Brown
provides various updates to some of the MM selftests to make them
play better with the overall containing framework.
* tag 'mm-stable-2025-06-01-14-06' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (43 commits)
mm/khugepaged: clean up refcount check using folio_expected_ref_count()
selftests/mm: fix test result reporting in gup_longterm
selftests/mm: report unique test names for each cow test
selftests/mm: add helper for logging test start and results
selftests/mm: use standard ksft_finished() in cow and gup_longterm
selftests/damon/_damon_sysfs: skip testcases if CONFIG_DAMON_SYSFS is disabled
sched/numa: add statistics of numa balance task
sched/numa: fix task swap by skipping kernel threads
tools/testing: check correct variable in open_procmap()
tools/testing/vma: add missing function stub
mm/gup: update comment explaining why gup_fast() disables IRQs
selftests/mm: two fixes for the pfnmap test
mm/khugepaged: fix race with folio split/free using temporary reference
mm: add CONFIG_PAGE_BLOCK_ORDER to select page block order
mmu_notifiers: remove leftover stub macros
selftests/mm: deduplicate test names in madv_populate
kcov: rust: add flags for KCOV with Rust
mm: rust: make CONFIG_MMU ifdefs more narrow
mmu_gather: move tlb flush for VM_PFNMAP/VM_MIXEDMAP vmas into free_pgtables()
mm/damon/Kconfig: enable CONFIG_DAMON by default
...
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git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse
Pull fuse updates from Miklos Szeredi:
- Remove tmp page copying in writeback path (Joanne).
This removes ~300 lines and with that a lot of complexity related to
avoiding reclaim related deadlock. The old mechanism is replaced with
a mapping flag that tells the MM not to block reclaim waiting for
writeback to complete. The MM parts have been reviewed/acked by
respective maintainers.
- Convert more code to handle large folios (Joanne). This still just
adds the code to deal with large folios and does not enable them yet.
- Allow invalidating all cached lookups atomically (Luis Henriques).
This feature is useful for CernVMFS, which currently does this
iteratively.
- Align write prefaulting in fuse with generic one (Dave Hansen)
- Fix race causing invalid data to be cached when setting attributes on
different nodes of a distributed fs (Guang Yuan Wu)
- Update documentation for passthrough (Chen Linxuan)
- Add fdinfo about the device number associated with an opened
/dev/fuse instance (Chen Linxuan)
- Increase readdir buffer size (Miklos). This depends on a patch to VFS
readdir code that was already merged through Christians tree.
- Optimize io-uring request expiration (Joanne)
- Misc cleanups
* tag 'fuse-update-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: (25 commits)
fuse: increase readdir buffer size
readdir: supply dir_context.count as readdir buffer size hint
fuse: don't allow signals to interrupt getdents copying
fuse: support large folios for writeback
fuse: support large folios for readahead
fuse: support large folios for queued writes
fuse: support large folios for stores
fuse: support large folios for symlinks
fuse: support large folios for folio reads
fuse: support large folios for writethrough writes
fuse: refactor fuse_fill_write_pages()
fuse: support large folios for retrieves
fuse: support copying large folios
fs: fuse: add dev id to /dev/fuse fdinfo
docs: filesystems: add fuse-passthrough.rst
MAINTAINERS: update filter of FUSE documentation
fuse: fix race between concurrent setattrs from multiple nodes
fuse: remove tmp folio for writebacks and internal rb tree
mm: skip folio reclaim in legacy memcg contexts for deadlockable mappings
fuse: optimize over-io-uring request expiration check
...
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs fixes from Christian Brauner:
- Fix the AT_HANDLE_CONNECTABLE option so filesystems that don't know
how to decode a connected non-dir dentry fail the request
- Use repr(transparent) to ensure identical layout between the C and
Rust implementation of struct file
- Add a missing xas_pause() into the dax code employing
wait_entry_unlocked_exclusive()
- Fix FOP_DONTCACHE which we disabled for v6.15.
A folio could get redirtied and/or scheduled for writeback after the
initial dropbehind test. Change the test accordingly to handle these
cases so we can re-enable FOP_DONTCACHE again
* tag 'vfs-6.16-rc2.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
exportfs: require ->fh_to_parent() to encode connectable file handles
rust: file: improve safety comments
rust: file: mark `LocalFile` as `repr(transparent)`
fs/dax: Fix "don't skip locked entries when scanning entries"
iomap: don't lose folio dropbehind state for overwrites
mm/filemap: unify dropbehind flag testing and clearing
mm/filemap: unify read/write dropbehind naming
Revert "Disable FOP_DONTCACHE for now due to bugs"
mm/filemap: use filemap_end_dropbehind() for read invalidation
mm/filemap: gate dropbehind invalidate on folio !dirty && !writeback
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Use folio_expected_ref_count() instead of open-coded logic in
is_refcount_suitable(). This avoids code duplication and improves
clarity.
Drop is_refcount_suitable() as it is no longer needed.
Link: https://lkml.kernel.org/r/20250526182818.37978-2-shivankg@amd.com
Signed-off-by: Shivank Garg <shivankg@amd.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Bharata B Rao <bharata@amd.com>
Cc: Fengwei Yin <fengwei.yin@intel.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
On systems with NUMA balancing enabled, it has been found that tracking
task activities resulting from NUMA balancing is beneficial. NUMA
balancing employs two mechanisms for task migration: one is to migrate
a task to an idle CPU within its preferred node, and the other is to
swap tasks located on different nodes when they are on each other's
preferred nodes.
The kernel already provides NUMA page migration statistics in
/sys/fs/cgroup/mytest/memory.stat and /proc/{PID}/sched. However, it
lacks statistics regarding task migration and swapping. Therefore,
relevant counts for task migration and swapping should be added.
The following two new fields:
numa_task_migrated
numa_task_swapped
will be shown in /sys/fs/cgroup/{GROUP}/memory.stat, /proc/{PID}/sched
and /proc/vmstat.
Introducing both per-task and per-memory cgroup (memcg) NUMA balancing
statistics facilitates a rapid evaluation of the performance and
resource utilization of the target workload. For instance, users can
first identify the container with high NUMA balancing activity and then
further pinpoint a specific task within that group, and subsequently
adjust the memory policy for that task. In short, although it is
possible to iterate through /proc/$pid/sched to locate the problematic
task, the introduction of aggregated NUMA balancing activity for tasks
within each memcg can assist users in identifying the task more
efficiently through a divide-and-conquer approach.
As Libo Chen pointed out, the memcg event relies on the text names in
vmstat_text, and /proc/vmstat generates corresponding items based on
vmstat_text. Thus, the relevant task migration and swapping events
introduced in vmstat_text also need to be populated by
count_vm_numa_event(), otherwise these values are zero in /proc/vmstat.
In theory, task migration and swap events are part of the scheduler's
activities. The reason for exposing them through the
memory.stat/vmstat interface is that we already have NUMA balancing
statistics in memory.stat/vmstat, and these events are closely related
to each other. Following Shakeel's suggestion, we describe the
end-to-end flow/story of all these events occurring on a timeline for
future reference:
The goal of NUMA balancing is to co-locate a task and its memory pages
on the same NUMA node. There are two strategies: migrate the pages to
the task's node, or migrate the task to the node where its pages
reside.
Suppose a task p1 is running on Node 0, but its pages are located on
Node 1. NUMA page fault statistics for p1 reveal its "page footprint"
across nodes. If NUMA balancing detects that most of p1's pages are on
Node 1:
1.Page Migration Attempt:
The Numa balance first tries to migrate p1's pages to Node 0.
The numa_page_migrate counter increments.
2.Task Migration Strategies:
After the page migration finishes, Numa balance checks every
1 second to see if p1 can be migrated to Node 1.
Case 2.1: Idle CPU Available
If Node 1 has an idle CPU, p1 is directly scheduled there. This
event is logged as numa_task_migrated.
Case 2.2: No Idle CPU (Task Swap)
If all CPUs on Node1 are busy, direct migration could cause CPU
contention or load imbalance. Instead: The Numa balance selects a
candidate task p2 on Node 1 that prefers Node 0 (e.g., due to its own
page footprint). p1 and p2 are swapped. This cross-node swap is
recorded as numa_task_swapped.
Link: https://lkml.kernel.org/r/d00edb12ba0f0de3c5222f61487e65f2ac58f5b1.1748493462.git.yu.c.chen@intel.com
Link: https://lkml.kernel.org/r/7ef90a88602ed536be46eba7152ed0d33bad5790.1748002400.git.yu.c.chen@intel.com
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Tested-by: Madadi Vineeth Reddy <vineethr@linux.ibm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: Aubrey Li <aubrey.li@intel.com>
Cc: Ayush Jain <Ayush.jain3@amd.com>
Cc: "Chen, Tim C" <tim.c.chen@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Libo Chen <libo.chen@oracle.com>
Cc: Mel Gorman <mgorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The current comment in gup_fast() talks about "IPIs that come from THPs
splitting", which is outdated and refers to the old THP splitting
implementation that was removed in commit ad0bed24e98b ("thp: drop all
split_huge_page()-related code"), which landed in v4.5. Before then, THP
splitting involved a pmdp_splitting_flush(), which sent an IPI to
serialize against gup_fast().
Nowadays, we use tlb_remove_table_sync_one() to send IPIs that serialize
against gup_fast(); this is used, for example, in THP *collapsing* to stop
gup_fast() walks of a page table before depositing it.
Link: https://lkml.kernel.org/r/20250528-gup-irq-comment-fix-v1-1-b9d83c345333@google.com
Signed-off-by: Jann Horn <jannh@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shuemov <kirill.shutemov@linux.intel.com>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
hpage_collapse_scan_file() calls is_refcount_suitable(), which in turn
calls folio_mapcount(). folio_mapcount() checks folio_test_large() before
proceeding to folio_large_mapcount(), but there is a race window where the
folio may get split/freed between these checks, triggering:
VM_WARN_ON_FOLIO(!folio_test_large(folio), folio)
Take a temporary reference to the folio in hpage_collapse_scan_file().
This stabilizes the folio during refcount check and prevents incorrect
large folio detection due to concurrent split/free. Use helper
folio_expected_ref_count() + 1 to compare with folio_ref_count() instead
of using is_refcount_suitable().
Link: https://lkml.kernel.org/r/20250526182818.37978-1-shivankg@amd.com
Fixes: 05c5323b2a34 ("mm: track mapcount of large folios in single value")
Signed-off-by: Shivank Garg <shivankg@amd.com>
Reported-by: syzbot+2b99589e33edbe9475ca@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/6828470d.a70a0220.38f255.000c.GAE@google.com
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Bharata B Rao <bharata@amd.com>
Cc: Fengwei Yin <fengwei.yin@intel.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Problem: On large page size configurations (16KiB, 64KiB), the CMA
alignment requirement (CMA_MIN_ALIGNMENT_BYTES) increases considerably,
and this causes the CMA reservations to be larger than necessary. This
means that system will have less available MIGRATE_UNMOVABLE and
MIGRATE_RECLAIMABLE page blocks since MIGRATE_CMA can't fallback to them.
The CMA_MIN_ALIGNMENT_BYTES increases because it depends on MAX_PAGE_ORDER
which depends on ARCH_FORCE_MAX_ORDER. The value of ARCH_FORCE_MAX_ORDER
increases on 16k and 64k kernels.
For example, in ARM, the CMA alignment requirement when:
- CONFIG_ARCH_FORCE_MAX_ORDER default value is used
- CONFIG_TRANSPARENT_HUGEPAGE is set:
PAGE_SIZE | MAX_PAGE_ORDER | pageblock_order | CMA_MIN_ALIGNMENT_BYTES
-----------------------------------------------------------------------
4KiB | 10 | 9 | 4KiB * (2 ^ 9) = 2MiB
16Kib | 11 | 11 | 16KiB * (2 ^ 11) = 32MiB
64KiB | 13 | 13 | 64KiB * (2 ^ 13) = 512MiB
There are some extreme cases for the CMA alignment requirement when:
- CONFIG_ARCH_FORCE_MAX_ORDER maximum value is set
- CONFIG_TRANSPARENT_HUGEPAGE is NOT set:
- CONFIG_HUGETLB_PAGE is NOT set
PAGE_SIZE | MAX_PAGE_ORDER | pageblock_order | CMA_MIN_ALIGNMENT_BYTES
------------------------------------------------------------------------
4KiB | 15 | 15 | 4KiB * (2 ^ 15) = 128MiB
16Kib | 13 | 13 | 16KiB * (2 ^ 13) = 128MiB
64KiB | 13 | 13 | 64KiB * (2 ^ 13) = 512MiB
This affects the CMA reservations for the drivers. If a driver in a
4KiB kernel needs 4MiB of CMA memory, in a 16KiB kernel, the minimal
reservation has to be 32MiB due to the alignment requirements:
reserved-memory {
...
cma_test_reserve: cma_test_reserve {
compatible = "shared-dma-pool";
size = <0x0 0x400000>; /* 4 MiB */
...
};
};
reserved-memory {
...
cma_test_reserve: cma_test_reserve {
compatible = "shared-dma-pool";
size = <0x0 0x2000000>; /* 32 MiB */
...
};
};
Solution: Add a new config CONFIG_PAGE_BLOCK_ORDER that allows to set the
page block order in all the architectures. The maximum page block order
will be given by ARCH_FORCE_MAX_ORDER.
By default, CONFIG_PAGE_BLOCK_ORDER will have the same value that
ARCH_FORCE_MAX_ORDER. This will make sure that current kernel
configurations won't be affected by this change. It is a opt-in change.
This patch will allow to have the same CMA alignment requirements for
large page sizes (16KiB, 64KiB) as that in 4kb kernels by setting a lower
pageblock_order.
Tests:
- Verified that HugeTLB pages work when pageblock_order is 1, 7, 10 on
4k and 16k kernels.
- Verified that Transparent Huge Pages work when pageblock_order is 1,
7, 10 on 4k and 16k kernels.
- Verified that dma-buf heaps allocations work when pageblock_order is
1, 7, 10 on 4k and 16k kernels.
Benchmarks:
The benchmarks compare 16kb kernels with pageblock_order 10 and 7. The
reason for the pageblock_order 7 is because this value makes the min CMA
alignment requirement the same as that in 4kb kernels (2MB).
- Perform 100K dma-buf heaps (/dev/dma_heap/system) allocations of
SZ_8M, SZ_4M, SZ_2M, SZ_1M, SZ_64, SZ_8, SZ_4. Use simpleperf
(https://developer.android.com/ndk/guides/simpleperf) to measure the #
of instructions and page-faults on 16k kernels. The benchmark was
executed 10 times. The averages are below:
# instructions | #page-faults
order 10 | order 7 | order 10 | order 7
--------------------------------------------------------
13,891,765,770 | 11,425,777,314 | 220 | 217
14,456,293,487 | 12,660,819,302 | 224 | 219
13,924,261,018 | 13,243,970,736 | 217 | 221
13,910,886,504 | 13,845,519,630 | 217 | 221
14,388,071,190 | 13,498,583,098 | 223 | 224
13,656,442,167 | 12,915,831,681 | 216 | 218
13,300,268,343 | 12,930,484,776 | 222 | 218
13,625,470,223 | 14,234,092,777 | 219 | 218
13,508,964,965 | 13,432,689,094 | 225 | 219
13,368,950,667 | 13,683,587,37 | 219 | 225
-------------------------------------------------------------------
13,803,137,433 | 13,131,974,268 | 220 | 220 Averages
There were 4.85% #instructions when order was 7, in comparison with order
10.
13,803,137,433 - 13,131,974,268 = -671,163,166 (-4.86%)
The number of page faults in order 7 and 10 were the same.
These results didn't show any significant regression when the
pageblock_order is set to 7 on 16kb kernels.
- Run speedometer 3.1 (https://browserbench.org/Speedometer3.1/) 5 times
on the 16k kernels with pageblock_order 7 and 10.
order 10 | order 7 | order 7 - order 10 | (order 7 - order 10) %
-------------------------------------------------------------------
15.8 | 16.4 | 0.6 | 3.80%
16.4 | 16.2 | -0.2 | -1.22%
16.6 | 16.3 | -0.3 | -1.81%
16.8 | 16.3 | -0.5 | -2.98%
16.6 | 16.8 | 0.2 | 1.20%
-------------------------------------------------------------------
16.44 16.4 -0.04 -0.24% Averages
The results didn't show any significant regression when the
pageblock_order is set to 7 on 16kb kernels.
Link: https://lkml.kernel.org/r/20250521215807.1860663-1-jyescas@google.com
Signed-off-by: Juan Yescas <jyescas@google.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Commit b67fbebd4cf9 ("mmu_gather: Force tlb-flush VM_PFNMAP vmas") added a
forced tlbflush to tlb_vma_end(), which is required to avoid a race
between munmap() and unmap_mapping_range(). However it added some
overhead to other paths where tlb_vma_end() is used, but vmas are not
removed, e.g. madvise(MADV_DONTNEED).
Fix this by moving the tlb flush out of tlb_end_vma() into new
tlb_flush_vmas() called from free_pgtables(), somewhat similar to the
stable version of the original commit: commit 895428ee124a ("mm: Force TLB
flush for PFNMAP mappings before unlink_file_vma()").
Note, that if tlb->fullmm is set, no flush is required, as the whole mm is
about to be destroyed.
Link: https://lkml.kernel.org/r/20250522012838.163876-1-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Jann Horn <jannh@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@kernel.org>
Cc: Nick Piggin <npiggin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
As of this writing, multiple major distros including Alma, Amazon,
Android, CentOS, Debian, Fedora, and Oracle are build-enabling DAMON (set
CONFIG_DAMON[1]). Enabling it by default will save configuration setup
time for the current and future DAMON users.
Build-enabling DAMON does not introduce a real risk since it makes no
behavioral change by default. It requires explicit user requests to do
anything. Only one potential risk is making the size of the kernel a
little bit larger. On a production-purpose configuration, it increases
the resulting kernel package size by about 0.1 % of the final package
file. I believe that's too small to be a real problem in common setups.
Hence, the benefit of enabling CONFIG_DAMON outweighs the potential risk.
Set CONFIG_DAMON by default.
Link: https://oracle.github.io/kconfigs/?config=UTS_RELEASE&config=DAMON [1]
Link: https://lkml.kernel.org/r/20250521042755.39653-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Acked-by: Honggyu Kim <honggyu.kim@sk.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm/damon: build-enable essential DAMON components by
default".
As of this writing, multiple major distros including Alma, Amazon,
Android, CentOS, Debian, Fedora, and Oracle are build-enabling DAMON (set
CONFIG_DAMON[1]). Configuring DAMON is not very easy, since it is
disabled by default, and there are multiple essential options that need to
be manually turned on, one by one. Make it easier, by grouping essential
configurations to be enabled with one selection, and enabling build of the
essential parts of DAMON by default.
Note that build-enabling DAMON does not introduce any real risk, since it
makes no behavioral change by default. It requires explicit user requests
to do anything. Only one potential risk is making the size of the kernel
a little bit larger. On a production-purpose configuration, it increases
the resulting kernel package binary size by about 0.1 % of the final
package file. I believe that's too small to be a real problem in common
setups.
DAMON_{VADDR,PADDR,SYSFS} are de-facto essential parts of DAMON for normal
usages. Because those need to be enabled one by one, however, and there
are other test-purpose or non-essential configurations, it is easy to be
confused and make mistakes at setup. Make the essential configurations
default to CONFIG_DAMON, so that those can be enabled by default with a
single change.
Link: https://oracle.github.io/kconfigs/?config=UTS_RELEASE&config=DAMON [1]
Link: https://lkml.kernel.org/r/20250521042755.39653-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20250521042755.39653-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Acked-by: Honggyu Kim <honggyu.kim@sk.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The number of pre-allocated huge pages should be nr_huge_pages, not
free_huge_pages, although they are same during booting stage
Link: https://lkml.kernel.org/r/20250515114231.65824-1-xuwenjie04@baidu.com
Signed-off-by: Wenjie Xu <xuwenjie04@baidu.com>
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Acked-by: Oscar Salvador <osalvador@suse.de>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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As only value entry will be added to fbatch in shmem_find_swap_entries(),
there is no need to do xa_is_value() check in shmem_unuse_swap_entries().
Link: https://lkml.kernel.org/r/20250516170939.965736-6-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Even if we fail to allocate a swap entry, the inode might have previously
allocated entry and we might take inode containing swap entry off
swaplist. As a result, try_to_unuse() may enter a potential dead loop to
repeatedly look for inode and clean it's swap entry. Only take inode off
swaplist when it's swapped page count is 0 to fix the issue.
Link: https://lkml.kernel.org/r/20250516170939.965736-5-shikemeng@huaweicloud.com
Fixes: b487a2da3575 ("mm, swap: simplify folio swap allocation")
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Kairui Song <kasong@tencent.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202505161438.9009cf47-lkp@intel.com
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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If multi shmem_unuse() for different swap type is called concurrently, a
dead loop could occur as following:
shmem_unuse(typeA) shmem_unuse(typeB)
mutex_lock(&shmem_swaplist_mutex)
list_for_each_entry_safe(info, next, ...)
...
mutex_unlock(&shmem_swaplist_mutex)
/* info->swapped may drop to 0 */
shmem_unuse_inode(&info->vfs_inode, type)
mutex_lock(&shmem_swaplist_mutex)
list_for_each_entry(info, next, ...)
if (!info->swapped)
list_del_init(&info->swaplist)
...
mutex_unlock(&shmem_swaplist_mutex)
mutex_lock(&shmem_swaplist_mutex)
/* iterate with offlist entry and encounter a dead loop */
next = list_next_entry(info, swaplist);
...
Restart the iteration if the inode is already off shmem_swaplist list to
fix the issue.
Link: https://lkml.kernel.org/r/20250516170939.965736-4-shikemeng@huaweicloud.com
Fixes: b56a2d8af914 ("mm: rid swapoff of quadratic complexity")
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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We will miss shmem_unacct_size() when is_idmapped_mnt() returns a failure.
Move is_idmapped_mnt() before shmem_acct_size() to fix the issue.
Link: https://lkml.kernel.org/r/20250516170939.965736-3-shikemeng@huaweicloud.com
Fixes: 7a80e5b8c6fa ("shmem: support idmapped mounts for tmpfs")
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "Some random fixes and cleanup to shmem", v3.
This series contains some simple fixes and cleanup which are made during
learning shmem. More details can be found in respective patches.
This patch (of 5):
If we get a folio from swap_cache_get_folio() successfully but encounter a
failure before the folio is locked, we will unlock the folio which was not
previously locked.
Put the folio and set it to NULL when a failure occurs before the folio is
locked to fix the issue.
Link: https://lkml.kernel.org/r/20250516170939.965736-1-shikemeng@huaweicloud.com
Link: https://lkml.kernel.org/r/20250516170939.965736-2-shikemeng@huaweicloud.com
Fixes: 058313515d5a ("mm: shmem: fix potential data corruption during shmem swapin")
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Kairui Song <kasong@tencent.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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When the number of the monitoring targets in running contexts is reduced,
there may be DAMOS quotas referencing the targets that will be destroyed.
Applying the scheme action for such DAMOS scheme will be skipped forever
looking for the starting part of the region for the destroyed monitoring
target.
To fix this issue, when the monitoring target is destroyed, reset the
starting part for all DAMOS quotas that reference the target.
Link: https://lkml.kernel.org/r/20250517141852.142802-1-akinobu.mita@gmail.com
Fixes: da87878010e5 ("mm/damon/sysfs: support online inputs update")
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Currently kernel maintains memory related stats updates per-cgroup to
optimize stats flushing. The stats_updates is defined as atomic64_t which
is not nmi-safe on some archs. Actually we don't really need 64bit atomic
as the max value stats_updates can get should be less than nr_cpus *
MEMCG_CHARGE_BATCH. A normal atomic_t should suffice.
Also the function cgroup_rstat_updated() is still not nmi-safe but there
is parallel effort to make it nmi-safe, so until then let's ignore it in
the nmi context.
Link: https://lkml.kernel.org/r/20250519063142.111219-6-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The objcg based kmem [un]charging can be called in nmi context and it may
need to update NR_SLAB_[UN]RECLAIMABLE_B stats. So, let's correctly
handle the updates of these stats in the nmi context.
Link: https://lkml.kernel.org/r/20250519063142.111219-5-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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