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EXT4-fs (loop6): unmounting filesystem 76b65be2-f6da-4727-8c75-0525a5b65a09.
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BUG: KCSAN: data-race in mlock_folio / need_mlock_drain

read-write to 0xffff888237d27010 of 1 bytes by task 27264 on cpu 1:
 folio_batch_add include/linux/pagevec.h:77 [inline]
 mlock_folio+0x14d/0x240 mm/mlock.c:257
 mlock_vma_folio mm/internal.h:1035 [inline]
 __folio_add_anon_rmap mm/rmap.c:1455 [inline]
 folio_add_anon_rmap_ptes+0x24e/0x250 mm/rmap.c:1478
 remove_migration_pte+0x873/0xca0 mm/migrate.c:432
 rmap_walk_anon+0x280/0x430 mm/rmap.c:2861
 rmap_walk+0x8b/0xd0 mm/rmap.c:2966
 remove_migration_ptes mm/migrate.c:472 [inline]
 migrate_folio_move mm/migrate.c:1391 [inline]
 migrate_folios_move mm/migrate.c:1721 [inline]
 migrate_pages_batch+0x165a/0x2400 mm/migrate.c:1977
 migrate_pages_sync mm/migrate.c:2007 [inline]
 migrate_pages+0x1079/0x18c0 mm/migrate.c:2116
 do_mbind mm/mempolicy.c:1609 [inline]
 kernel_mbind mm/mempolicy.c:1752 [inline]
 __do_sys_mbind mm/mempolicy.c:1826 [inline]
 __se_sys_mbind+0xc9c/0xde0 mm/mempolicy.c:1822
 __x64_sys_mbind+0x78/0x90 mm/mempolicy.c:1822
 x64_sys_call+0x2a2b/0x3000 arch/x86/include/generated/asm/syscalls_64.h:238
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc0/0x2a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237d27010 of 1 bytes by task 11017 on cpu 0:
 folio_batch_count include/linux/pagevec.h:56 [inline]
 need_mlock_drain+0x30/0x50 mm/mlock.c:235
 cpu_needs_drain mm/swap.c:786 [inline]
 __lru_add_drain_all+0x273/0x450 mm/swap.c:877
 lru_add_drain_all+0x10/0x20 mm/swap.c:893
 invalidate_bdev+0x47/0x70 block/bdev.c:101
 ext4_put_super+0x624/0x7d0 fs/ext4/super.c:1348
 generic_shutdown_super+0xe6/0x210 fs/super.c:643
 kill_block_super+0x2a/0x70 fs/super.c:1722
 ext4_kill_sb+0x42/0x80 fs/ext4/super.c:7444
 deactivate_locked_super+0x75/0x1c0 fs/super.c:474
 deactivate_super+0x97/0xa0 fs/super.c:507
 cleanup_mnt+0x2bb/0x330 fs/namespace.c:1318
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1325
 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:44 [inline]
 exit_to_user_mode_loop+0x1f7/0x6f0 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x1d3/0x2a0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 11017 Comm: syz-executor 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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