EXT4-fs (loop5): unmounting filesystem 00000000-0000-0000-0000-000000000000.
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BUG: KCSAN: data-race in __lru_add_drain_all / folio_add_lru

read-write to 0xffff888237c26528 of 1 bytes by task 13597 on cpu 0:
 folio_batch_add include/linux/folio_batch.h:77 [inline]
 __folio_batch_add_and_move mm/swap.c:229 [inline]
 folio_add_lru+0xa5/0x250 mm/swap.c:562
 shmem_alloc_and_add_folio mm/shmem.c:2018 [inline]
 shmem_get_folio_gfp+0x7cc/0xd90 mm/shmem.c:2512
 shmem_get_folio mm/shmem.c:2618 [inline]
 shmem_fallocate+0x5ef/0x8f0 mm/shmem.c:3712
 vfs_fallocate+0x3ac/0x400 fs/open.c:338
 ksys_fallocate fs/open.c:362 [inline]
 __do_sys_fallocate fs/open.c:367 [inline]
 __se_sys_fallocate fs/open.c:365 [inline]
 __x64_sys_fallocate+0x7a/0xd0 fs/open.c:365
 x64_sys_call+0x1e1d/0x2550 arch/x86/include/generated/asm/syscalls_64.h:286
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237c26528 of 1 bytes by task 12133 on cpu 1:
 folio_batch_count include/linux/folio_batch.h:56 [inline]
 cpu_needs_drain mm/swap.c:831 [inline]
 __lru_add_drain_all+0x180/0x450 mm/swap.c:928
 lru_add_drain_all+0x10/0x20 mm/swap.c:944
 invalidate_bdev+0x47/0x70 block/bdev.c:101
 ext4_put_super+0x614/0x7c0 fs/ext4/super.c:1355
 generic_shutdown_super+0xee/0x220 fs/super.c:769
 kill_block_super+0x2d/0xb0 fs/super.c:1918
 ext4_kill_sb+0x42/0x80 fs/ext4/super.c:7507
 deactivate_locked_super+0x75/0x200 fs/super.c:603
 deactivate_super+0x9a/0xb0 fs/super.c:632
 cleanup_mnt+0x2c3/0x340 fs/namespace.c:1317
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1324
 task_work_run+0x130/0x1a0 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
 exit_to_user_mode_loop+0x1e4/0x8c0 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:336 [inline]
 do_syscall_64+0x212/0x360 arch/x86/entry/syscall_64.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x17 -> 0x19

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 12133 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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