EXT4-fs (loop0): unmounting filesystem 00000000-0000-0000-0000-000000000000.
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BUG: KCSAN: data-race in find_get_block_common / has_bh_in_lru

read-write to 0xffff888237d277f8 of 8 bytes by task 16697 on cpu 1:
 bh_lru_install fs/buffer.c:1230 [inline]
 find_get_block_common+0x4ae/0x870 fs/buffer.c:1295
 bdev_getblk+0x4c/0x3c0 include/linux/gfp.h:-1
 __bread_gfp+0x51/0x240 fs/buffer.c:1400
 sb_bread include/linux/buffer_head.h:344 [inline]
 fat_ent_bread+0xbe/0x1a0 fs/fat/fatent.c:109
 fat_ent_read+0x3b6/0x5c0 fs/fat/fatent.c:372
 fat_get_cluster+0x4f8/0x830 fs/fat/cache.c:261
 fat_free fs/fat/file.c:349 [inline]
 fat_truncate_blocks+0x284/0x5b0 fs/fat/file.c:397
 fat_write_failed fs/fat/inode.c:219 [inline]
 fat_write_end+0xba/0x160 fs/fat/inode.c:247
 generic_perform_write+0x314/0x490 mm/filemap.c:4395
 __generic_file_write_iter+0x9e/0x120 mm/filemap.c:4491
 generic_file_write_iter+0x77/0x1f0 mm/filemap.c:4517
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x57f/0x9a0 fs/read_write.c:687
 ksys_write+0xdc/0x1a0 fs/read_write.c:739
 __do_sys_write fs/read_write.c:750 [inline]
 __se_sys_write fs/read_write.c:747 [inline]
 __x64_sys_write+0x40/0x50 fs/read_write.c:747
 x64_sys_call+0x154e/0x2550 arch/x86/include/generated/asm/syscalls_64.h:2
 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 0xffff888237d277f8 of 8 bytes by task 15089 on cpu 0:
 has_bh_in_lru+0x8c/0x1f0 fs/buffer.c:1436
 cpu_needs_drain mm/folio.c:768 [inline]
 __lru_add_drain_all+0x2c1/0x520 mm/folio.c:860
 lru_add_drain_all+0x10/0x20 mm/folio.c:876
 invalidate_bdev+0x47/0x70 block/bdev.c:100
 ext4_put_super+0x620/0x7c0 fs/ext4/super.c:1357
 generic_shutdown_super+0xee/0x220 fs/super.c:751
 kill_block_super+0x2d/0xb0 fs/super.c:1903
 ext4_kill_sb+0x42/0x80 fs/ext4/super.c:7528
 deactivate_locked_super+0x73/0x180 fs/super.c:586
 deactivate_super+0x9a/0xb0 fs/super.c:614
 cleanup_mnt+0x143/0x1c0 fs/namespace.c:1392
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1399
 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:343 [inline]
 do_syscall_64+0x212/0x360 arch/x86/entry/syscall_64.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000000 -> 0xffff88811a92f0c0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 15089 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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