EXT4-fs (loop3): unmounting filesystem 00000000-0000-0000-0000-000000000000.
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BUG: KCSAN: data-race in __lru_add_drain_all / folios_put_refs

write to 0xffff888237d266e8 of 1 bytes by task 12137 on cpu 1:
 folio_batch_reinit include/linux/folio_batch.h:50 [inline]
 folios_put_refs+0x28f/0x2d0 mm/swap.c:1002
 folios_put include/linux/mm.h:2149 [inline]
 folio_batch_move_lru+0x263/0x290 mm/swap.c:179
 lru_add_drain_cpu+0x66/0x210 mm/swap.c:654
 lru_add_drain+0x25/0x70 mm/swap.c:743
 wp_can_reuse_anon_folio mm/memory.c:4185 [inline]
 do_wp_page+0xf96/0x2040 mm/memory.c:4299
 handle_pte_fault mm/memory.c:6427 [inline]
 __handle_mm_fault mm/memory.c:6549 [inline]
 handle_mm_fault+0x8b9/0x2e70 mm/memory.c:6718
 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 0xffff888237d266e8 of 1 bytes by task 12126 on cpu 0:
 folio_batch_count include/linux/folio_batch.h:56 [inline]
 cpu_needs_drain mm/swap.c:786 [inline]
 __lru_add_drain_all+0x17e/0x450 mm/swap.c:883
 lru_add_drain_all+0x10/0x20 mm/swap.c:899
 invalidate_bdev+0x47/0x70 block/bdev.c:101
 ext4_put_super+0x610/0x7b0 fs/ext4/super.c:1355
 generic_shutdown_super+0xee/0x220 fs/super.c:646
 kill_block_super+0x2a/0x70 fs/super.c:1725
 ext4_kill_sb+0x42/0x80 fs/ext4/super.c:7492
 deactivate_locked_super+0x75/0x1c0 fs/super.c:476
 deactivate_super+0x97/0xa0 fs/super.c:509
 cleanup_mnt+0x2bb/0x330 fs/namespace.c:1312
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1319
 task_work_run+0x130/0x1a0 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x4ae/0x1530 kernel/exit.c:975
 do_group_exit+0xfe/0x140 kernel/exit.c:1117
 get_signal+0xe30/0xf20 kernel/signal.c:3037
 arch_do_signal_or_restart+0x96/0x450 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x6a/0x6f0 kernel/entry/common.c:98
 __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:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x232/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x04 -> 0x03

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 12126 Comm: syz.3.9087 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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