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BUG: KCSAN: data-race in find_get_block_common / has_bh_in_lru

read-write to 0xffff888237d275e0 of 8 bytes by task 3285 on cpu 1:
 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
 __getblk include/linux/buffer_head.h:382 [inline]
 sb_getblk include/linux/buffer_head.h:388 [inline]
 __ext4_get_inode_loc+0x311/0x930 fs/ext4/inode.c:4891
 ext4_get_inode_loc fs/ext4/inode.c:5019 [inline]
 ext4_reserve_inode_write+0xd7/0x250 fs/ext4/inode.c:6424
 __ext4_mark_inode_dirty+0x8c/0x3d0 fs/ext4/inode.c:6602
 ext4_dirty_inode+0x92/0xc0 fs/ext4/inode.c:6639
 __mark_inode_dirty+0x164/0x700 fs/fs-writeback.c:2709
 generic_update_time fs/inode.c:2257 [inline]
 file_update_time_flags+0x29b/0x2e0 fs/inode.c:2487
 file_update_time+0x17/0x20 fs/inode.c:2508
 ext4_page_mkwrite+0x15d/0xa90 fs/ext4/inode.c:6805
 do_page_mkwrite mm/memory.c:3684 [inline]
 wp_page_shared mm/memory.c:4085 [inline]
 do_wp_page+0xc50/0x2030 mm/memory.c:4304
 handle_pte_fault mm/memory.c:6395 [inline]
 __handle_mm_fault mm/memory.c:6517 [inline]
 handle_mm_fault+0x8bc/0x2da0 mm/memory.c:6686
 do_user_addr_fault+0x634/0x1060 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 0xffff888237d275e0 of 8 bytes by task 3295 on cpu 0:
 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
 kill_bdev block/bdev.c:90 [inline]
 blkdev_flush_mapping+0x94/0x1a0 block/bdev.c:715
 blkdev_put_whole block/bdev.c:722 [inline]
 bdev_release+0x2c1/0x3d0 block/bdev.c:1147
 blkdev_release+0x15/0x20 block/fops.c:680
 __fput+0x29e/0x630 fs/file_table.c:512
 ____fput+0x1c/0x30 fs/file_table.c:540
 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: 0xffff888104f8f480 -> 0xffff8881005dc8a0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3295 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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