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BUG: KCSAN: data-race in find_get_block_common / has_bh_in_lru

read-write to 0xffff888237d27ce0 of 8 bytes by task 3289 on cpu 1:
 bh_lru_install fs/buffer.c:1234 [inline]
 find_get_block_common+0x457/0x870 fs/buffer.c:1299
 bdev_getblk+0x4b/0x370 fs/buffer.c:-1
 __getblk include/linux/buffer_head.h:436 [inline]
 sb_getblk include/linux/buffer_head.h:442 [inline]
 __ext4_get_inode_loc+0x311/0x970 fs/ext4/inode.c:5714
 ext4_get_inode_loc fs/ext4/inode.c:5842 [inline]
 ext4_reserve_inode_write+0xd7/0x250 fs/ext4/inode.c:7424
 __ext4_mark_inode_dirty+0x87/0x430 fs/ext4/inode.c:7618
 ext4_dirty_inode+0x92/0xc0 fs/ext4/inode.c:7655
 __mark_inode_dirty+0x164/0x700 fs/fs-writeback.c:2751
 generic_update_time fs/inode.c:2263 [inline]
 file_update_time_flags+0x299/0x2d0 fs/inode.c:2493
 file_update_time+0x17/0x20 fs/inode.c:2514
 ext4_page_mkwrite+0x15e/0xc70 fs/ext4/inode.c:7840
 do_page_mkwrite mm/memory.c:3889 [inline]
 wp_page_shared mm/memory.c:4295 [inline]
 do_wp_page+0xbae/0x1ea0 mm/memory.c:4518
 handle_pte_fault mm/memory.c:6692 [inline]
 __handle_mm_fault mm/memory.c:6817 [inline]
 handle_mm_fault+0xe44/0x3bd0 mm/memory.c:6984
 do_user_addr_fault+0x3ce/0xde0 arch/x86/mm/fault.c:1343
 handle_page_fault arch/x86/mm/fault.c:1483 [inline]
 exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1536
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595

read to 0xffff888237d27ce0 of 8 bytes by task 3306 on cpu 0:
 has_bh_in_lru+0x35/0x1f0 fs/buffer.c:1440
 smp_call_function_many_cond+0x2d1/0xbc0 kernel/smp.c:962
 on_each_cpu_cond_mask+0x35/0x50 kernel/smp.c:1195
 on_each_cpu_cond include/linux/smp.h:105 [inline]
 invalidate_bh_lrus+0x2a/0x30 fs/buffer.c:1449
 kill_bdev block/bdev.c:89 [inline]
 blkdev_flush_mapping+0x94/0x1a0 block/bdev.c:757
 blkdev_put_whole block/bdev.c:764 [inline]
 bdev_release+0x2c1/0x3d0 block/bdev.c:1189
 blkdev_release+0x15/0x20 block/fops.c:690
 __fput+0x286/0x610 fs/file_table.c:512
 ____fput+0x1c/0x30 fs/file_table.c:541
 task_work_run+0x133/0x190 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+0x216/0x380 arch/x86/entry/syscall_64.c:107
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000000 -> 0xffff8881060708a0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3306 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
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