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BUG: KCSAN: data-race in find_get_block_common / has_bh_in_lru

read-write to 0xffff888237d26f70 of 8 bytes by task 12022 on cpu 1:
 bh_lru_install fs/buffer.c:1351 [inline]
 find_get_block_common+0x4f0/0x960 fs/buffer.c:1416
 __find_get_block_nonatomic fs/buffer.c:1435 [inline]
 bdev_getblk+0x83/0x3d0 fs/buffer.c:1459
 __bread_gfp+0x51/0x250 fs/buffer.c:1521
 sb_bread include/linux/buffer_head.h:348 [inline]
 fat_ent_bread+0xc9/0x1a0 fs/fat/fatent.c:109
 fat_ent_read+0x3ad/0x5a0 fs/fat/fatent.c:368
 fat_get_cluster+0x4b2/0x7b0 fs/fat/cache.c:266
 fat_free fs/fat/file.c:346 [inline]
 fat_truncate_blocks+0x27d/0x550 fs/fat/file.c:394
 fat_write_failed fs/fat/inode.c:218 [inline]
 fat_write_end+0xba/0x160 fs/fat/inode.c:244
 generic_perform_write+0x312/0x490 mm/filemap.c:4124
 __generic_file_write_iter+0x9e/0x120 mm/filemap.c:4220
 generic_file_write_iter+0x8d/0x2f0 mm/filemap.c:4246
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x4a0/0x8e0 fs/read_write.c:686
 ksys_pwrite64 fs/read_write.c:793 [inline]
 __do_sys_pwrite64 fs/read_write.c:801 [inline]
 __se_sys_pwrite64 fs/read_write.c:798 [inline]
 __x64_sys_pwrite64+0xfd/0x150 fs/read_write.c:798
 x64_sys_call+0xe45/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:19
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237d26f70 of 8 bytes by task 3329 on cpu 0:
 has_bh_in_lru+0x35/0x1f0 fs/buffer.c:1557
 cpu_needs_drain mm/swap.c:780 [inline]
 __lru_add_drain_all+0x234/0x3f0 mm/swap.c:867
 lru_add_drain_all+0x10/0x20 mm/swap.c:883
 invalidate_bdev+0x47/0x70 block/bdev.c:101
 ext4_put_super+0x624/0x7d0 fs/ext4/super.c:1339
 generic_shutdown_super+0xe6/0x210 fs/super.c:643
 kill_block_super+0x2a/0x70 fs/super.c:1760
 ext4_kill_sb+0x42/0x80 fs/ext4/super.c:7391
 deactivate_locked_super+0x75/0x1c0 fs/super.c:474
 deactivate_super+0x97/0xa0 fs/super.c:507
 cleanup_mnt+0x269/0x2e0 fs/namespace.c:1432
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1439
 task_work_run+0x12e/0x1a0 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xe4/0x100 kernel/entry/common.c:114
 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
 do_syscall_64+0x1d6/0x200 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000000 -> 0xffff888111603ea0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3329 Comm: syz-executor Not tainted 6.15.0-syzkaller-08486-gf66bc387efbe #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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