EXT4-fs (loop2): 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 0xffff888237c275e0 of 8 bytes by task 7187 on cpu 0:
 bh_lru_install fs/buffer.c:1323 [inline]
 find_get_block_common+0x45c/0x870 fs/buffer.c:1388
 bdev_getblk+0x4c/0x3c0 include/linux/gfp.h:-1
 __bread_gfp+0x51/0x240 fs/buffer.c:1493
 sb_bread include/linux/buffer_head.h:348 [inline]
 __fat_write_inode+0x151/0x540 fs/fat/inode.c:877
 fat_sync_inode+0x1a/0x30 fs/fat/inode.c:935
 fat_free fs/fat/file.c:336 [inline]
 fat_truncate_blocks+0x1df/0x5b0 fs/fat/file.c:398
 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:4379
 __generic_file_write_iter+0x9e/0x120 mm/filemap.c:4475
 generic_file_write_iter+0x77/0x1f0 mm/filemap.c:4501
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x57d/0x990 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+0x27e1/0x3020 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237c275e0 of 8 bytes by task 29199 on cpu 1:
 has_bh_in_lru+0x35/0x1f0 fs/buffer.c:1529
 smp_call_function_many_cond+0x297/0xb60 kernel/smp.c:856
 on_each_cpu_cond_mask+0x3c/0x80 kernel/smp.c:1077
 on_each_cpu_cond include/linux/smp.h:106 [inline]
 invalidate_bh_lrus+0x2a/0x30 fs/buffer.c:1538
 invalidate_bdev+0x42/0x70 block/bdev.c:100
 ext4_put_super+0x614/0x7c0 fs/ext4/super.c:1355
 generic_shutdown_super+0xee/0x220 fs/super.c:647
 kill_block_super+0x2a/0x70 fs/super.c:1671
 ext4_kill_sb+0x42/0x80 fs/ext4/super.c:7499
 deactivate_locked_super+0x75/0x1c0 fs/super.c:477
 deactivate_super+0x97/0xa0 fs/super.c:510
 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:318 [inline]
 do_syscall_64+0x23c/0x3c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff888134ef0d20 -> 0xffff88810812a660

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 29199 Comm: syz-executor Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
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