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BUG: KCSAN: data-race in find_get_block_common / has_bh_in_lru

read-write to 0xffff888237c26f20 of 8 bytes by task 7696 on cpu 0:
 bh_lru_install fs/buffer.c:1351 [inline]
 find_get_block_common+0x528/0x960 fs/buffer.c:1416
 __find_get_block_nonatomic fs/buffer.c:1435 [inline]
 bdev_getblk+0x83/0x3d0 fs/buffer.c:1459
 __getblk include/linux/buffer_head.h:382 [inline]
 sb_getblk include/linux/buffer_head.h:388 [inline]
 ext4_read_block_bitmap_nowait+0x168/0x680 fs/ext4/balloc.c:488
 ext4_read_block_bitmap+0x1e/0x70 fs/ext4/balloc.c:600
 ext4_discard_preallocations+0x3ba/0x960 fs/ext4/mballoc.c:5598
 ext4_truncate+0x69c/0xad0 fs/ext4/inode.c:4571
 ext4_truncate_failed_write fs/ext4/truncate.h:22 [inline]
 ext4_write_end+0x44b/0x730 fs/ext4/inode.c:1465
 ext4_da_write_end+0x70/0x810 fs/ext4/inode.c:3208
 generic_perform_write+0x312/0x490 mm/filemap.c:4133
 ext4_buffered_write_iter+0x1ee/0x3c0 fs/ext4/file.c:299
 ext4_file_write_iter+0x383/0xf00 fs/ext4/file.c:-1
 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 0xffff888237c26f20 of 8 bytes by task 3315 on cpu 1:
 has_bh_in_lru+0x70/0x1f0 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:1753
 ext4_kill_sb+0x42/0x80 fs/ext4/super.c:7391
 deactivate_locked_super+0x72/0x1c0 fs/super.c:474
 deactivate_super+0x97/0xa0 fs/super.c:507
 cleanup_mnt+0x269/0x2e0 fs/namespace.c:1417
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1424
 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 -> 0xffff8881200758f0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3315 Comm: syz-executor Not tainted 6.16.0-rc1-syzkaller-00239-g08215f5486ec #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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