Merge tag 'v6.6.75' into for/openbmc/dev-6.6

This is the 6.6.75 stable release

cachestat: fix page cache statistics permission checking

commit 5f537664e705b0bf8b7e329861f20128534f6a83 upstream.

When the 'cachestat()' system call was added in commit cf264e1329fb
("cachestat: i

cachestat: fix page cache statistics permission checking

commit 5f537664e705b0bf8b7e329861f20128534f6a83 upstream.

When the 'cachestat()' system call was added in commit cf264e1329fb
("cachestat: implement cachestat syscall"), it was meant to be a much
more convenient (and performant) version of mincore() that didn't need
mapping things into the user virtual address space in order to work.

But it ended up missing the "check for writability or ownership" fix for
mincore(), done in commit 134fca9063ad ("mm/mincore.c: make mincore()
more conservative").

This just adds equivalent logic to 'cachestat()', modified for the file
context (rather than vma).

Reported-by: Sudheendra Raghav Neela <sneela@tugraz.at>
Fixes: cf264e1329fb ("cachestat: implement cachestat syscall")
Tested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

Merge tag 'v6.6.74' into for/openbmc/dev-6.6

This is the 6.6.74 stable release

filemap: avoid truncating 64-bit offset to 32 bits

commit f505e6c91e7a22d10316665a86d79f84d9f0ba76 upstream.

On 32-bit kernels, folio_seek_hole_data() was inadvertently truncating a
64-bit value to

filemap: avoid truncating 64-bit offset to 32 bits

commit f505e6c91e7a22d10316665a86d79f84d9f0ba76 upstream.

On 32-bit kernels, folio_seek_hole_data() was inadvertently truncating a
64-bit value to 32 bits, leading to a possible infinite loop when writing
to an xfs filesystem.

Link: https://lkml.kernel.org/r/20250102190540.1356838-1-marco.nelissen@gmail.com
Fixes: 54fa39ac2e00 ("iomap: use mapping_seek_hole_data")
Signed-off-by: Marco Nelissen <marco.nelissen@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

Merge tag 'v6.6.62' into for/openbmc/dev-6.6

This is the 6.6.62 stable release

mm: support order-1 folios in the page cache

commit 8897277acfef7f70fdecc054073bea2542fc7a1b upstream.

Folios of order 1 have no space to store the deferred list. This is not a
problem for the pag

mm: support order-1 folios in the page cache

commit 8897277acfef7f70fdecc054073bea2542fc7a1b upstream.

Folios of order 1 have no space to store the deferred list. This is not a
problem for the page cache as file-backed folios are never placed on the
deferred list. All we need to do is prevent the core MM from touching the
deferred list for order 1 folios and remove the code which prevented us
from allocating order 1 folios.

Link: https://lore.kernel.org/linux-mm/90344ea7-4eec-47ee-5996-0c22f42d6a6a@google.com/
Link: https://lkml.kernel.org/r/20240226205534.1603748-3-zi.yan@sent.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Zi Yan <ziy@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Michal Koutny <mkoutny@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

Merge tag 'v6.6.61' into for/openbmc/dev-6.6

This is the 6.6.61 stable release

filemap: Fix bounds checking in filemap_read()

commit ace149e0830c380ddfce7e466fe860ca502fe4ee upstream.

If the caller supplies an iocb->ki_pos value that is close to the
filesystem upper limit, an

filemap: Fix bounds checking in filemap_read()

commit ace149e0830c380ddfce7e466fe860ca502fe4ee upstream.

If the caller supplies an iocb->ki_pos value that is close to the
filesystem upper limit, and an iterator with a count that causes us to
overflow that limit, then filemap_read() enters an infinite loop.

This behaviour was discovered when testing xfstests generic/525 with the
"localio" optimisation for loopback NFS mounts.

Reported-by: Mike Snitzer <snitzer@kernel.org>
Fixes: c2a9737f45e2 ("vfs,mm: fix a dead loop in truncate_inode_pages_range()")
Tested-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

Merge tag 'v6.6.54' into for/openbmc/dev-6.6

This is the 6.6.54 stable release

mm/filemap: optimize filemap folio adding

commit 6758c1128ceb45d1a35298912b974eb4895b7dd9 upstream.

Instead of doing multiple tree walks, do one optimism range check with
lock hold, and exit if rac

mm/filemap: optimize filemap folio adding

commit 6758c1128ceb45d1a35298912b974eb4895b7dd9 upstream.

Instead of doing multiple tree walks, do one optimism range check with
lock hold, and exit if raced with another insertion. If a shadow exists,
check it with a new xas_get_order helper before releasing the lock to
avoid redundant tree walks for getting its order.

Drop the lock and do the allocation only if a split is needed.

In the best case, it only need to walk the tree once. If it needs to
alloc and split, 3 walks are issued (One for first ranged conflict check
and order retrieving, one for the second check after allocation, one for
the insert after split).

Testing with 4K pages, in an 8G cgroup, with 16G brd as block device:

echo 3 > /proc/sys/vm/drop_caches

fio -name=cached --numjobs=16 --filename=/mnt/test.img \
--buffered=1 --ioengine=mmap --rw=randread --time_based \
--ramp_time=30s --runtime=5m --group_reporting

Before:
bw ( MiB/s): min= 1027, max= 3520, per=100.00%, avg=2445.02, stdev=18.90, samples=8691
iops : min=263001, max=901288, avg=625924.36, stdev=4837.28, samples=8691

After (+7.3%):
bw ( MiB/s): min= 493, max= 3947, per=100.00%, avg=2625.56, stdev=25.74, samples=8651
iops : min=126454, max=1010681, avg=672142.61, stdev=6590.48, samples=8651

Test result with THP (do a THP randread then switch to 4K page in hope it
issues a lot of splitting):

echo 3 > /proc/sys/vm/drop_caches

fio -name=cached --numjobs=16 --filename=/mnt/test.img \
--buffered=1 --ioengine=mmap -thp=1 --readonly \
--rw=randread --time_based --ramp_time=30s --runtime=10m \
--group_reporting

fio -name=cached --numjobs=16 --filename=/mnt/test.img \
--buffered=1 --ioengine=mmap \
--rw=randread --time_based --runtime=5s --group_reporting

Before:
bw ( KiB/s): min= 4141, max=14202, per=100.00%, avg=7935.51, stdev=96.85, samples=18976
iops : min= 1029, max= 3548, avg=1979.52, stdev=24.23, samples=18976·

READ: bw=4545B/s (4545B/s), 4545B/s-4545B/s (4545B/s-4545B/s), io=64.0KiB (65.5kB), run=14419-14419msec

After (+12.5%):
bw ( KiB/s): min= 4611, max=15370, per=100.00%, avg=8928.74, stdev=105.17, samples=19146
iops : min= 1151, max= 3842, avg=2231.27, stdev=26.29, samples=19146

READ: bw=4635B/s (4635B/s), 4635B/s-4635B/s (4635B/s-4635B/s), io=64.0KiB (65.5kB), run=14137-14137msec

The performance is better for both 4K (+7.5%) and THP (+12.5%) cached read.

Link: https://lkml.kernel.org/r/20240415171857.19244-5-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Closes: https://lore.kernel.org/linux-mm/A5A976CB-DB57-4513-A700-656580488AB6@flyingcircus.io/
[ kasong@tencent.com: minor adjustment of variable declarations ]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

mm/filemap: return early if failed to allocate memory for split

commit de60fd8ddeda2b41fbe11df11733838c5f684616 upstream.

xas_split_alloc could fail with NOMEM, and in such case, it should abort
ea

mm/filemap: return early if failed to allocate memory for split

commit de60fd8ddeda2b41fbe11df11733838c5f684616 upstream.

xas_split_alloc could fail with NOMEM, and in such case, it should abort
early instead of keep going and fail the xas_split below.

Link: https://lkml.kernel.org/r/20240416071722.45997-1-ryncsn@gmail.com
Link: https://lkml.kernel.org/r/20240415171857.19244-1-ryncsn@gmail.com
Link: https://lkml.kernel.org/r/20240415171857.19244-2-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Acked-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: 6758c1128ceb ("mm/filemap: optimize filemap folio adding")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

Merge tag 'v6.6.42' into dev-6.6

This is the 6.6.42 stable release

mm: page_ref: remove folio_try_get_rcu()

commit fa2690af573dfefb47ba6eef888797a64b6b5f3c upstream.

The below bug was reported on a non-SMP kernel:

[ 275.267158][ T4335] ------------[ cut here ]--

mm: page_ref: remove folio_try_get_rcu()

commit fa2690af573dfefb47ba6eef888797a64b6b5f3c upstream.

The below bug was reported on a non-SMP kernel:

[ 275.267158][ T4335] ------------[ cut here ]------------
[ 275.267949][ T4335] kernel BUG at include/linux/page_ref.h:275!
[ 275.268526][ T4335] invalid opcode: 0000 [#1] KASAN PTI
[ 275.269001][ T4335] CPU: 0 PID: 4335 Comm: trinity-c3 Not tainted 6.7.0-rc4-00061-gefa7df3e3bb5 #1
[ 275.269787][ T4335] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[ 275.270679][ T4335] RIP: 0010:try_get_folio (include/linux/page_ref.h:275 (discriminator 3) mm/gup.c:79 (discriminator 3))
[ 275.272813][ T4335] RSP: 0018:ffffc90005dcf650 EFLAGS: 00010202
[ 275.273346][ T4335] RAX: 0000000000000246 RBX: ffffea00066e0000 RCX: 0000000000000000
[ 275.274032][ T4335] RDX: fffff94000cdc007 RSI: 0000000000000004 RDI: ffffea00066e0034
[ 275.274719][ T4335] RBP: ffffea00066e0000 R08: 0000000000000000 R09: fffff94000cdc006
[ 275.275404][ T4335] R10: ffffea00066e0037 R11: 0000000000000000 R12: 0000000000000136
[ 275.276106][ T4335] R13: ffffea00066e0034 R14: dffffc0000000000 R15: ffffea00066e0008
[ 275.276790][ T4335] FS: 00007fa2f9b61740(0000) GS:ffffffff89d0d000(0000) knlGS:0000000000000000
[ 275.277570][ T4335] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 275.278143][ T4335] CR2: 00007fa2f6c00000 CR3: 0000000134b04000 CR4: 00000000000406f0
[ 275.278833][ T4335] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 275.279521][ T4335] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 275.280201][ T4335] Call Trace:
[ 275.280499][ T4335] <TASK>
[ 275.280751][ T4335] ? die (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:434 arch/x86/kernel/dumpstack.c:447)
[ 275.281087][ T4335] ? do_trap (arch/x86/kernel/traps.c:112 arch/x86/kernel/traps.c:153)
[ 275.281463][ T4335] ? try_get_folio (include/linux/page_ref.h:275 (discriminator 3) mm/gup.c:79 (discriminator 3))
[ 275.281884][ T4335] ? try_get_folio (include/linux/page_ref.h:275 (discriminator 3) mm/gup.c:79 (discriminator 3))
[ 275.282300][ T4335] ? do_error_trap (arch/x86/kernel/traps.c:174)
[ 275.282711][ T4335] ? try_get_folio (include/linux/page_ref.h:275 (discriminator 3) mm/gup.c:79 (discriminator 3))
[ 275.283129][ T4335] ? handle_invalid_op (arch/x86/kernel/traps.c:212)
[ 275.283561][ T4335] ? try_get_folio (include/linux/page_ref.h:275 (discriminator 3) mm/gup.c:79 (discriminator 3))
[ 275.283990][ T4335] ? exc_invalid_op (arch/x86/kernel/traps.c:264)
[ 275.284415][ T4335] ? asm_exc_invalid_op (arch/x86/include/asm/idtentry.h:568)
[ 275.284859][ T4335] ? try_get_folio (include/linux/page_ref.h:275 (discriminator 3) mm/gup.c:79 (discriminator 3))
[ 275.285278][ T4335] try_grab_folio (mm/gup.c:148)
[ 275.285684][ T4335] __get_user_pages (mm/gup.c:1297 (discriminator 1))
[ 275.286111][ T4335] ? __pfx___get_user_pages (mm/gup.c:1188)
[ 275.286579][ T4335] ? __pfx_validate_chain (kernel/locking/lockdep.c:3825)
[ 275.287034][ T4335] ? mark_lock (kernel/locking/lockdep.c:4656 (discriminator 1))
[ 275.287416][ T4335] __gup_longterm_locked (mm/gup.c:1509 mm/gup.c:2209)
[ 275.288192][ T4335] ? __pfx___gup_longterm_locked (mm/gup.c:2204)
[ 275.288697][ T4335] ? __pfx_lock_acquire (kernel/locking/lockdep.c:5722)
[ 275.289135][ T4335] ? __pfx___might_resched (kernel/sched/core.c:10106)
[ 275.289595][ T4335] pin_user_pages_remote (mm/gup.c:3350)
[ 275.290041][ T4335] ? __pfx_pin_user_pages_remote (mm/gup.c:3350)
[ 275.290545][ T4335] ? find_held_lock (kernel/locking/lockdep.c:5244 (discriminator 1))
[ 275.290961][ T4335] ? mm_access (kernel/fork.c:1573)
[ 275.291353][ T4335] process_vm_rw_single_vec+0x142/0x360
[ 275.291900][ T4335] ? __pfx_process_vm_rw_single_vec+0x10/0x10
[ 275.292471][ T4335] ? mm_access (kernel/fork.c:1573)
[ 275.292859][ T4335] process_vm_rw_core+0x272/0x4e0
[ 275.293384][ T4335] ? hlock_class (arch/x86/include/asm/bitops.h:227 arch/x86/include/asm/bitops.h:239 include/asm-generic/bitops/instrumented-non-atomic.h:142 kernel/locking/lockdep.c:228)
[ 275.293780][ T4335] ? __pfx_process_vm_rw_core+0x10/0x10
[ 275.294350][ T4335] process_vm_rw (mm/process_vm_access.c:284)
[ 275.294748][ T4335] ? __pfx_process_vm_rw (mm/process_vm_access.c:259)
[ 275.295197][ T4335] ? __task_pid_nr_ns (include/linux/rcupdate.h:306 (discriminator 1) include/linux/rcupdate.h:780 (discriminator 1) kernel/pid.c:504 (discriminator 1))
[ 275.295634][ T4335] __x64_sys_process_vm_readv (mm/process_vm_access.c:291)
[ 275.296139][ T4335] ? syscall_enter_from_user_mode (kernel/entry/common.c:94 kernel/entry/common.c:112)
[ 275.296642][ T4335] do_syscall_64 (arch/x86/entry/common.c:51 (discriminator 1) arch/x86/entry/common.c:82 (discriminator 1))
[ 275.297032][ T4335] ? __task_pid_nr_ns (include/linux/rcupdate.h:306 (discriminator 1) include/linux/rcupdate.h:780 (discriminator 1) kernel/pid.c:504 (discriminator 1))
[ 275.297470][ T4335] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4300 kernel/locking/lockdep.c:4359)
[ 275.297988][ T4335] ? do_syscall_64 (arch/x86/include/asm/cpufeature.h:171 arch/x86/entry/common.c:97)
[ 275.298389][ T4335] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4300 kernel/locking/lockdep.c:4359)
[ 275.298906][ T4335] ? do_syscall_64 (arch/x86/include/asm/cpufeature.h:171 arch/x86/entry/common.c:97)
[ 275.299304][ T4335] ? do_syscall_64 (arch/x86/include/asm/cpufeature.h:171 arch/x86/entry/common.c:97)
[ 275.299703][ T4335] ? do_syscall_64 (arch/x86/include/asm/cpufeature.h:171 arch/x86/entry/common.c:97)
[ 275.300115][ T4335] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:129)

This BUG is the VM_BUG_ON(!in_atomic() && !irqs_disabled()) assertion in
folio_ref_try_add_rcu() for non-SMP kernel.

The process_vm_readv() calls GUP to pin the THP. An optimization for
pinning THP instroduced by commit 57edfcfd3419 ("mm/gup: accelerate thp
gup even for "pages != NULL"") calls try_grab_folio() to pin the THP,
but try_grab_folio() is supposed to be called in atomic context for
non-SMP kernel, for example, irq disabled or preemption disabled, due to
the optimization introduced by commit e286781d5f2e ("mm: speculative
page references").

The commit efa7df3e3bb5 ("mm: align larger anonymous mappings on THP
boundaries") is not actually the root cause although it was bisected to.
It just makes the problem exposed more likely.

The follow up discussion suggested the optimization for non-SMP kernel
may be out-dated and not worth it anymore [1]. So removing the
optimization to silence the BUG.

However calling try_grab_folio() in GUP slow path actually is
unnecessary, so the following patch will clean this up.

[1] https://lore.kernel.org/linux-mm/821cf1d6-92b9-4ac4-bacc-d8f2364ac14f@paulmck-laptop/

Link: https://lkml.kernel.org/r/20240625205350.1777481-1-yang@os.amperecomputing.com
Fixes: 57edfcfd3419 ("mm/gup: accelerate thp gup even for "pages != NULL"")
Signed-off-by: Yang Shi <yang@os.amperecomputing.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Tested-by: Oliver Sang <oliver.sang@intel.com>
Acked-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Vivek Kasireddy <vivek.kasireddy@intel.com>
Cc: <stable@vger.kernel.org> [6.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

Merge tag 'v6.6.41' into dev-6.6

This is the 6.6.41 stable release

mm/filemap: skip to create PMD-sized page cache if needed

commit 3390916aca7af1893ed2ebcdfee1d6fdb65bb058 upstream.

On ARM64, HPAGE_PMD_ORDER is 13 when the base page size is 64KB. The
PMD-sized p

mm/filemap: skip to create PMD-sized page cache if needed

commit 3390916aca7af1893ed2ebcdfee1d6fdb65bb058 upstream.

On ARM64, HPAGE_PMD_ORDER is 13 when the base page size is 64KB. The
PMD-sized page cache can't be supported by xarray as the following error
messages indicate.

------------[ cut here ]------------
WARNING: CPU: 35 PID: 7484 at lib/xarray.c:1025 xas_split_alloc+0xf8/0x128
Modules linked in: nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib \
nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct \
nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 \
ip_set rfkill nf_tables nfnetlink vfat fat virtio_balloon drm \
fuse xfs libcrc32c crct10dif_ce ghash_ce sha2_ce sha256_arm64 \
sha1_ce virtio_net net_failover virtio_console virtio_blk failover \
dimlib virtio_mmio
CPU: 35 PID: 7484 Comm: test Kdump: loaded Tainted: G W 6.10.0-rc5-gavin+ #9
Hardware name: QEMU KVM Virtual Machine, BIOS edk2-20240524-1.el9 05/24/2024
pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : xas_split_alloc+0xf8/0x128
lr : split_huge_page_to_list_to_order+0x1c4/0x720
sp : ffff800087a4f6c0
x29: ffff800087a4f6c0 x28: ffff800087a4f720 x27: 000000001fffffff
x26: 0000000000000c40 x25: 000000000000000d x24: ffff00010625b858
x23: ffff800087a4f720 x22: ffffffdfc0780000 x21: 0000000000000000
x20: 0000000000000000 x19: ffffffdfc0780000 x18: 000000001ff40000
x17: 00000000ffffffff x16: 0000018000000000 x15: 51ec004000000000
x14: 0000e00000000000 x13: 0000000000002000 x12: 0000000000000020
x11: 51ec000000000000 x10: 51ece1c0ffff8000 x9 : ffffbeb961a44d28
x8 : 0000000000000003 x7 : ffffffdfc0456420 x6 : ffff0000e1aa6eb8
x5 : 20bf08b4fe778fca x4 : ffffffdfc0456420 x3 : 0000000000000c40
x2 : 000000000000000d x1 : 000000000000000c x0 : 0000000000000000
Call trace:
xas_split_alloc+0xf8/0x128
split_huge_page_to_list_to_order+0x1c4/0x720
truncate_inode_partial_folio+0xdc/0x160
truncate_inode_pages_range+0x1b4/0x4a8
truncate_pagecache_range+0x84/0xa0
xfs_flush_unmap_range+0x70/0x90 [xfs]
xfs_file_fallocate+0xfc/0x4d8 [xfs]
vfs_fallocate+0x124/0x2e8
ksys_fallocate+0x4c/0xa0
__arm64_sys_fallocate+0x24/0x38
invoke_syscall.constprop.0+0x7c/0xd8
do_el0_svc+0xb4/0xd0
el0_svc+0x44/0x1d8
el0t_64_sync_handler+0x134/0x150
el0t_64_sync+0x17c/0x180

Fix it by skipping to allocate PMD-sized page cache when its size is
larger than MAX_PAGECACHE_ORDER. For this specific case, we will fall to
regular path where the readahead window is determined by BDI's sysfs file
(read_ahead_kb).

Link: https://lkml.kernel.org/r/20240627003953.1262512-4-gshan@redhat.com
Fixes: 4687fdbb805a ("mm/filemap: Support VM_HUGEPAGE for file mappings")
Signed-off-by: Gavin Shan <gshan@redhat.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Zhenyu Zhang <zhenyzha@redhat.com>
Cc: <stable@vger.kernel.org> [5.18+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

Merge tag 'v6.6.24' into dev-6.6

This is the 6.6.24 stable release

mm: cachestat: fix two shmem bugs

commit d5d39c707a4cf0bcc84680178677b97aa2cb2627 upstream.

When cachestat on shmem races with swapping and invalidation, there
are two possible bugs:

1) A swapin e

mm: cachestat: fix two shmem bugs

commit d5d39c707a4cf0bcc84680178677b97aa2cb2627 upstream.

When cachestat on shmem races with swapping and invalidation, there
are two possible bugs:

1) A swapin error can have resulted in a poisoned swap entry in the
shmem inode's xarray. Calling get_shadow_from_swap_cache() on it
will result in an out-of-bounds access to swapper_spaces[].

Validate the entry with non_swap_entry() before going further.

2) When we find a valid swap entry in the shmem's inode, the shadow
entry in the swapcache might not exist yet: swap IO is still in
progress and we're before __remove_mapping; swapin, invalidation,
or swapoff have removed the shadow from swapcache after we saw the
shmem swap entry.

This will send a NULL to workingset_test_recent(). The latter
purely operates on pointer bits, so it won't crash - node 0, memcg
ID 0, eviction timestamp 0, etc. are all valid inputs - but it's a
bogus test. In theory that could result in a false "recently
evicted" count.

Such a false positive wouldn't be the end of the world. But for
code clarity and (future) robustness, be explicit about this case.

Bail on get_shadow_from_swap_cache() returning NULL.

Link: https://lkml.kernel.org/r/20240315095556.GC581298@cmpxchg.org
Fixes: cf264e1329fb ("cachestat: implement cachestat syscall")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Chengming Zhou <chengming.zhou@linux.dev> [Bug #1]
Reported-by: Jann Horn <jannh@google.com> [Bug #2]
Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: <stable@vger.kernel.org> [v6.5+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Merge tag 'v6.6.21' into dev-6.6

This is the 6.6.21 stable release

mm: cachestat: fix folio read-after-free in cache walk

commit 3a75cb05d53f4a6823a32deb078de1366954a804 upstream.

In cachestat, we access the folio from the page cache's xarray to compute
its page o

mm: cachestat: fix folio read-after-free in cache walk

commit 3a75cb05d53f4a6823a32deb078de1366954a804 upstream.

In cachestat, we access the folio from the page cache's xarray to compute
its page offset, and check for its dirty and writeback flags. However, we
do not hold a reference to the folio before performing these actions,
which means the folio can concurrently be released and reused as another
folio/page/slab.

Get around this altogether by just using xarray's existing machinery for
the folio page offsets and dirty/writeback states.

This changes behavior for tmpfs files to now always report zeroes in their
dirty and writeback counters. This is okay as tmpfs doesn't follow
conventional writeback cache behavior: its pages get "cleaned" during
swapout, after which they're no longer resident etc.

Link: https://lkml.kernel.org/r/20240220153409.GA216065@cmpxchg.org
Fixes: cf264e1329fb ("cachestat: implement cachestat syscall")
Reported-by: Jann Horn <jannh@google.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: Jann Horn <jannh@google.com>
Cc: <stable@vger.kernel.org> [6.4+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Merge tag 'v6.6.10' into dev-6.6

This is the 6.6.10 stable release

Merge tag 'v6.6.7' into dev-6.6

This is the 6.6.7 stable release

mm/filemap: avoid buffered read/write race to read inconsistent data

commit e2c27b803bb664748e090d99042ac128b3f88d92 upstream.

The following concurrency may cause the data read to be inconsistent w

mm/filemap: avoid buffered read/write race to read inconsistent data

commit e2c27b803bb664748e090d99042ac128b3f88d92 upstream.

The following concurrency may cause the data read to be inconsistent with
the data on disk:

cpu1 cpu2
------------------------------|------------------------------
// Buffered write 2048 from 0
ext4_buffered_write_iter
generic_perform_write
copy_page_from_iter_atomic
ext4_da_write_end
ext4_da_do_write_end
block_write_end
__block_commit_write
folio_mark_uptodate
// Buffered read 4096 from 0 smp_wmb()
ext4_file_read_iter set_bit(PG_uptodate, folio_flags)
generic_file_read_iter i_size_write // 2048
filemap_read unlock_page(page)
filemap_get_pages
filemap_get_read_batch
folio_test_uptodate(folio)
ret = test_bit(PG_uptodate, folio_flags)
if (ret)
smp_rmb();
// Ensure that the data in page 0-2048 is up-to-date.

// New buffered write 2048 from 2048
ext4_buffered_write_iter
generic_perform_write
copy_page_from_iter_atomic
ext4_da_write_end
ext4_da_do_write_end
block_write_end
__block_commit_write
folio_mark_uptodate
smp_wmb()
set_bit(PG_uptodate, folio_flags)
i_size_write // 4096
unlock_page(page)

isize = i_size_read(inode) // 4096
// Read the latest isize 4096, but without smp_rmb(), there may be
// Load-Load disorder resulting in the data in the 2048-4096 range
// in the page is not up-to-date.
copy_page_to_iter
// copyout 4096

In the concurrency above, we read the updated i_size, but there is no read
barrier to ensure that the data in the page is the same as the i_size at
this point, so we may copy the unsynchronized page out. Hence adding the
missing read memory barrier to fix this.

This is a Load-Load reordering issue, which only occurs on some weak
mem-ordering architectures (e.g. ARM64, ALPHA), but not on strong
mem-ordering architectures (e.g. X86). And theoretically the problem
doesn't only happen on ext4, filesystems that call filemap_read() but
don't hold inode lock (e.g. btrfs, f2fs, ubifs ...) will have this
problem, while filesystems with inode lock (e.g. xfs, nfs) won't have
this problem.

Link: https://lkml.kernel.org/r/20231213062324.739009-1-libaokun1@huawei.com
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: yangerkun <yangerkun@huawei.com>
Cc: Yu Kuai <yukuai3@huawei.com>
Cc: Zhang Yi <yi.zhang@huawei.com>
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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mm: fix oops when filemap_map_pmd() without prealloc_pte

commit 9aa1345d66b8132745ffb99b348b1492088da9e2 upstream.

syzbot reports oops in lockdep's __lock_acquire(), called from
__pte_offset_map_lo

mm: fix oops when filemap_map_pmd() without prealloc_pte

commit 9aa1345d66b8132745ffb99b348b1492088da9e2 upstream.

syzbot reports oops in lockdep's __lock_acquire(), called from
__pte_offset_map_lock() called from filemap_map_pages(); or when I run the
repro, the oops comes in pmd_install(), called from filemap_map_pmd()
called from filemap_map_pages(), just before the __pte_offset_map_lock().

The problem is that filemap_map_pmd() has been assuming that when it finds
pmd_none(), a page table has already been prepared in prealloc_pte; and
indeed do_fault_around() has been careful to preallocate one there, when
it finds pmd_none(): but what if *pmd became none in between?

My 6.6 mods in mm/khugepaged.c, avoiding mmap_lock for write, have made it
easy for *pmd to be cleared while servicing a page fault; but even before
those, a huge *pmd might be zapped while a fault is serviced.

The difference in symptomatic stack traces comes from the "memory model"
in use: pmd_install() uses pmd_populate() uses page_to_pfn(): in some
models that is strict, and will oops on the NULL prealloc_pte; in other
models, it will construct a bogus value to be populated into *pmd, then
__pte_offset_map_lock() oops when trying to access split ptlock pointer
(or some other symptom in normal case of ptlock embedded not pointer).

Link: https://lore.kernel.org/linux-mm/20231115065506.19780-1-jose.pekkarinen@foxhound.fi/
Link: https://lkml.kernel.org/r/6ed0c50c-78ef-0719-b3c5-60c0c010431c@google.com
Fixes: f9ce0be71d1f ("mm: Cleanup faultaround and finish_fault() codepaths")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reported-and-tested-by: syzbot+89edd67979b52675ddec@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-mm/0000000000005e44550608a0806c@google.com/
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Jann Horn <jannh@google.com>,
Cc: José Pekkarinen <jose.pekkarinen@foxhound.fi>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org> [5.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Merge tag 'mm-hotfixes-stable-2023-10-01-08-34' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
"Fourteen hotfixes, eleven of which are cc:stable. The r

Merge tag 'mm-hotfixes-stable-2023-10-01-08-34' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
"Fourteen hotfixes, eleven of which are cc:stable. The remainder
pertain to issues which were introduced after 6.5"

* tag 'mm-hotfixes-stable-2023-10-01-08-34' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
Crash: add lock to serialize crash hotplug handling
selftests/mm: fix awk usage in charge_reserved_hugetlb.sh and hugetlb_reparenting_test.sh that may cause error
mm: mempolicy: keep VMA walk if both MPOL_MF_STRICT and MPOL_MF_MOVE are specified
mm/damon/vaddr-test: fix memory leak in damon_do_test_apply_three_regions()
mm, memcg: reconsider kmem.limit_in_bytes deprecation
mm: zswap: fix potential memory corruption on duplicate store
arm64: hugetlb: fix set_huge_pte_at() to work with all swap entries
mm: hugetlb: add huge page size param to set_huge_pte_at()
maple_tree: add MAS_UNDERFLOW and MAS_OVERFLOW states
maple_tree: add mas_is_active() to detect in-tree walks
nilfs2: fix potential use after free in nilfs_gccache_submit_read_data()
mm: abstract moving to the next PFN
mm: report success more often from filemap_map_folio_range()
fs: binfmt_elf_efpic: fix personality for ELF-FDPIC

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mm: report success more often from filemap_map_folio_range()

Even though we had successfully mapped the relevant page, we would rarely
return success from filemap_map_folio_range(). That leads to f

mm: report success more often from filemap_map_folio_range()

Even though we had successfully mapped the relevant page, we would rarely
return success from filemap_map_folio_range(). That leads to falling back
from the VMA lock path to the mmap_lock path, which is a speed &
scalability issue. Found by inspection.

Link: https://lkml.kernel.org/r/20230920035336.854212-1-willy@infradead.org
Fixes: 617c28ecab22 ("filemap: batch PTE mappings")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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