syzbot

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BUG: KCSAN: data-race in find_get_block_common / has_bh_in_lru

read-write to 0xffff888237d26f10 of 8 bytes by task 3290 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
 __getblk include/linux/buffer_head.h:382 [inline]
 sb_getblk include/linux/buffer_head.h:388 [inline]
 __ext4_get_inode_loc+0x303/0x930 fs/ext4/inode.c:4797
 ext4_get_inode_loc fs/ext4/inode.c:4925 [inline]
 ext4_reserve_inode_write+0xd7/0x250 fs/ext4/inode.c:6244
 __ext4_mark_inode_dirty+0x8c/0x3f0 fs/ext4/inode.c:6422
 ext4_dirty_inode+0x92/0xc0 fs/ext4/inode.c:6459
 __mark_inode_dirty+0x15f/0x760 fs/fs-writeback.c:2527
 generic_update_time fs/inode.c:2064 [inline]
 inode_update_time fs/inode.c:2077 [inline]
 __file_update_time fs/inode.c:2305 [inline]
 file_update_time+0x288/0x2b0 fs/inode.c:2335
 ext4_page_mkwrite+0x18b/0xba0 fs/ext4/inode.c:6577
 do_page_mkwrite mm/memory.c:3378 [inline]
 wp_page_shared mm/memory.c:3779 [inline]
 do_wp_page+0xe5a/0x2400 mm/memory.c:3998
 handle_pte_fault mm/memory.c:6085 [inline]
 __handle_mm_fault mm/memory.c:6212 [inline]
 handle_mm_fault+0x77d/0x2be0 mm/memory.c:6381
 do_user_addr_fault+0x636/0x1090 arch/x86/mm/fault.c:1336
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

read to 0xffff888237d26f10 of 8 bytes by task 6711 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:1755
 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:1417
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1424
 task_work_run+0x131/0x1a0 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 -> 0xffff8881069841a0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 6711 Comm: syz-executor Not tainted 6.16.0-rc5-syzkaller-00266-g3f31a806a62e #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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