[moderation] [cgroups?] [mm?] KCSAN: data-race in mem_cgroup_track_foreign_dirty_slowpath / mem_cgroup_track_foreign_dirty_slowpath (9)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 372800cb95a3 Merge tag 'for-6.19-rc4-tag' of git://git.ker..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=105049fc580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b319ff1b6a2797ca
dashboard link: https://syzkaller.appspot.com/bug?extid=346193c9e07ec5006acd
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
CC: [ak...@linux-foundation.org cgr...@vger.kernel.org han...@cmpxchg.org linux-...@vger.kernel.org linu...@kvack.org mho...@kernel.org muchu...@linux.dev roman.g...@linux.dev shakee...@linux.dev]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8543bb0498db/disk-372800cb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/66027c524d0e/vmlinux-372800cb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2f88be755a57/bzImage-372800cb.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+346193...@syzkaller.appspotmail.com

ext4 filesystem being mounted at /100/file1 supports timestamps until 2038-01-19 (0x7fffffff)
==================================================================
BUG: KCSAN: data-race in mem_cgroup_track_foreign_dirty_slowpath / mem_cgroup_track_foreign_dirty_slowpath

write to 0xffff88811b370568 of 8 bytes by task 15762 on cpu 0:
mem_cgroup_track_foreign_dirty_slowpath+0x321/0x440 mm/memcontrol.c:3504
mem_cgroup_track_foreign_dirty include/linux/memcontrol.h:1540 [inline]
folio_account_dirtied mm/page-writeback.c:2664 [inline]
__folio_mark_dirty+0x3c2/0x4a0 mm/page-writeback.c:2711
mark_buffer_dirty+0x11e/0x210 fs/buffer.c:1206
block_commit_write fs/buffer.c:2218 [inline]
block_page_mkwrite+0x287/0x3d0 fs/buffer.c:2643
ext4_page_mkwrite+0x859/0xb90 fs/ext4/inode.c:6689
do_page_mkwrite mm/memory.c:3528 [inline]
do_shared_fault mm/memory.c:5831 [inline]
do_fault mm/memory.c:5893 [inline]
do_pte_missing mm/memory.c:4401 [inline]
handle_pte_fault mm/memory.c:6273 [inline]
__handle_mm_fault mm/memory.c:6411 [inline]
handle_mm_fault+0x1601/0x2c60 mm/memory.c:6580
do_user_addr_fault+0x630/0x1080 arch/x86/mm/fault.c:1336
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618

read to 0xffff88811b370568 of 8 bytes by task 15766 on cpu 1:
mem_cgroup_track_foreign_dirty_slowpath+0xd5/0x440 mm/memcontrol.c:3484
mem_cgroup_track_foreign_dirty include/linux/memcontrol.h:1540 [inline]
folio_account_dirtied mm/page-writeback.c:2664 [inline]
__folio_mark_dirty+0x3c2/0x4a0 mm/page-writeback.c:2711
mark_buffer_dirty+0x11e/0x210 fs/buffer.c:1206
folio_zero_new_buffers+0x28c/0x2e0 fs/buffer.c:2032
block_write_end+0x200/0x210 fs/buffer.c:2289
ext4_da_do_write_end fs/ext4/inode.c:3218 [inline]
ext4_da_write_end+0x1d3/0x800 fs/ext4/inode.c:3292
generic_perform_write+0x312/0x490 mm/filemap.c:4335
ext4_buffered_write_iter+0x1ee/0x3c0 fs/ext4/file.c:299
ext4_file_write_iter+0x387/0xf60 fs/ext4/file.c:-1
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x52a/0x960 fs/read_write.c:686
ksys_write+0xda/0x1a0 fs/read_write.c:738
__do_sys_write fs/read_write.c:749 [inline]
__se_sys_write fs/read_write.c:746 [inline]
__x64_sys_write+0x40/0x50 fs/read_write.c:746
x64_sys_call+0x2847/0x3000 arch/x86/include/generated/asm/syscalls_64.h:2
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000100010166 -> 0x00000001000101ce

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 15766 Comm: syz.0.14954 Tainted: G W syzkaller #0 PREEMPT(voluntary)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================


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