==================================================================
BUG: KCSAN: data-race in __lru_add_drain_all / folio_batch_move_lru

write to 0xffff888237c29e88 of 1 bytes by task 1671 on cpu 0:
 folio_batch_reinit include/linux/pagevec.h:48 [inline]
 folio_batch_move_lru+0x2bf/0x2f0 mm/swap.c:225
 folio_batch_add_and_move mm/swap.c:234 [inline]
 folio_activate+0x15c/0x1c0 mm/swap.c:361
 folio_mark_accessed+0x119/0x190 mm/swap.c:481
 shmem_get_folio_gfp+0x7e7/0xb40 mm/shmem.c:2007
 shmem_get_folio mm/shmem.c:2134 [inline]
 shmem_write_begin+0xa0/0x1b0 mm/shmem.c:2717
 generic_perform_write+0x1c9/0x410 mm/filemap.c:3930
 shmem_file_write_iter+0xc8/0xe0 mm/shmem.c:2893
 do_iter_readv_writev+0x2b0/0x330
 vfs_iter_write+0x270/0x5a0 fs/read_write.c:895
 lo_write_bvec drivers/block/loop.c:246 [inline]
 lo_write_simple drivers/block/loop.c:267 [inline]
 do_req_filebacked drivers/block/loop.c:491 [inline]
 loop_handle_cmd drivers/block/loop.c:1909 [inline]
 loop_process_work+0xacb/0x10e0 drivers/block/loop.c:1944
 loop_rootcg_workfn+0x22/0x30 drivers/block/loop.c:1975
 process_one_work kernel/workqueue.c:2633 [inline]
 process_scheduled_works+0x5b8/0xa40 kernel/workqueue.c:2706
 worker_thread+0x525/0x730 kernel/workqueue.c:2787
 kthread+0x1d7/0x210 kernel/kthread.c:388
 ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

read to 0xffff888237c29e88 of 1 bytes by task 31478 on cpu 1:
 folio_batch_count include/linux/pagevec.h:53 [inline]
 cpu_needs_drain mm/swap.c:800 [inline]
 __lru_add_drain_all+0x21d/0x420 mm/swap.c:889
 lru_add_drain_all+0x10/0x20 mm/swap.c:905
 invalidate_bdev+0x54/0x70 block/bdev.c:89
 ext4_put_super+0x51b/0x7e0 fs/ext4/super.c:1361
 generic_shutdown_super+0xdb/0x210 fs/super.c:646
 kill_block_super+0x2a/0x60 fs/super.c:1680
 ext4_kill_sb+0x44/0x80 fs/ext4/super.c:7319
 deactivate_locked_super+0x7a/0x1c0 fs/super.c:477
 deactivate_super+0x9b/0xb0 fs/super.c:510
 cleanup_mnt+0x272/0x2e0 fs/namespace.c:1267
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1274
 task_work_run+0x135/0x1a0 kernel/task_work.c:180
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:108 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline]
 syscall_exit_to_user_mode+0xbd/0x130 kernel/entry/common.c:212
 do_syscall_64+0xda/0x1d0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0f -> 0x08

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 31478 Comm: syz-executor.4 Not tainted 6.8.0-rc4-syzkaller-00180-g4f5e5092fdbf #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
==================================================================
EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.