syzbot

EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback.
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BUG: KCSAN: data-race in mem_cgroup_track_foreign_dirty_slowpath / mem_cgroup_track_foreign_dirty_slowpath

write to 0xffff88810021cd68 of 8 bytes by task 23879 on cpu 1:
 mem_cgroup_track_foreign_dirty_slowpath+0x321/0x460 mm/memcontrol.c:3525
 mem_cgroup_track_foreign_dirty include/linux/memcontrol.h:1554 [inline]
 folio_account_dirtied mm/page-writeback.c:2620 [inline]
 __folio_mark_dirty+0x3c1/0x4a0 mm/page-writeback.c:2667
 mark_buffer_dirty+0x120/0x220 fs/buffer.c:1204
 block_commit_write fs/buffer.c:2216 [inline]
 block_page_mkwrite+0x287/0x3c0 fs/buffer.c:2641
 ext4_page_mkwrite+0x859/0xb90 fs/ext4/inode.c:6637
 do_page_mkwrite mm/memory.c:3581 [inline]
 do_shared_fault mm/memory.c:5866 [inline]
 do_fault mm/memory.c:5928 [inline]
 do_pte_missing mm/memory.c:4469 [inline]
 handle_pte_fault mm/memory.c:6308 [inline]
 __handle_mm_fault mm/memory.c:6446 [inline]
 handle_mm_fault+0x18f2/0x3020 mm/memory.c:6615
 do_user_addr_fault+0x62f/0x1050 arch/x86/mm/fault.c:1334
 handle_page_fault arch/x86/mm/fault.c:1474 [inline]
 exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1527
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618

read to 0xffff88810021cd68 of 8 bytes by task 23880 on cpu 0:
 mem_cgroup_track_foreign_dirty_slowpath+0xd5/0x460 mm/memcontrol.c:3505
 mem_cgroup_track_foreign_dirty include/linux/memcontrol.h:1554 [inline]
 folio_account_dirtied mm/page-writeback.c:2620 [inline]
 __folio_mark_dirty+0x3c1/0x4a0 mm/page-writeback.c:2667
 mark_buffer_dirty+0x120/0x220 fs/buffer.c:1204
 folio_zero_new_buffers+0x28c/0x2e0 fs/buffer.c:2030
 block_write_end+0x200/0x210 fs/buffer.c:2287
 ext4_write_end+0x133/0x750 fs/ext4/inode.c:1446
 ext4_da_write_end+0x65/0x810 fs/ext4/inode.c:3271
 generic_perform_write+0x311/0x490 mm/filemap.c:4335
 ext4_buffered_write_iter+0x1ee/0x3c0 fs/ext4/file.c:300
 ext4_file_write_iter+0x380/0xfa0 fs/ext4/file.c:-1
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x5a6/0x9f0 fs/read_write.c:688
 ksys_pwrite64 fs/read_write.c:795 [inline]
 __do_sys_pwrite64 fs/read_write.c:803 [inline]
 __se_sys_pwrite64 fs/read_write.c:800 [inline]
 __x64_sys_pwrite64+0xfd/0x150 fs/read_write.c:800
 x64_sys_call+0xa2a/0x3020 arch/x86/include/generated/asm/syscalls_64.h:19
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x000000010000cc59 -> 0x000000010000ccfb

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 23880 Comm: syz.0.6348 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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