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BUG: KCSAN: data-race in find_get_block_common / has_bh_in_lru

read-write to 0xffff888237c27550 of 8 bytes by task 3311 on cpu 0:
 bh_lru_install fs/buffer.c:1345 [inline]
 find_get_block_common+0x4f3/0x950 fs/buffer.c:1410
 bdev_getblk+0x4d/0x3f0 include/linux/gfp.h:-1
 __getblk include/linux/buffer_head.h:380 [inline]
 sb_getblk include/linux/buffer_head.h:386 [inline]
 __ext4_get_inode_loc+0x303/0x930 fs/ext4/inode.c:4835
 ext4_get_inode_loc fs/ext4/inode.c:4963 [inline]
 ext4_reserve_inode_write+0xd7/0x250 fs/ext4/inode.c:6287
 __ext4_mark_inode_dirty+0x8c/0x3f0 fs/ext4/inode.c:6465
 ext4_dirty_inode+0x92/0xc0 fs/ext4/inode.c:6502
 __mark_inode_dirty+0x162/0x750 fs/fs-writeback.c:2587
 generic_update_time fs/inode.c:2155 [inline]
 inode_update_time fs/inode.c:2168 [inline]
 file_update_time_flags+0x2e5/0x310 fs/inode.c:2395
 file_update_time+0x17/0x20 fs/inode.c:2416
 ext4_page_mkwrite+0x18c/0xb90 fs/ext4/inode.c:6668
 do_page_mkwrite mm/memory.c:3528 [inline]
 wp_page_shared mm/memory.c:3929 [inline]
 do_wp_page+0xa77/0x2510 mm/memory.c:4148
 handle_pte_fault mm/memory.c:6289 [inline]
 __handle_mm_fault mm/memory.c:6411 [inline]
 handle_mm_fault+0x7b0/0x2c60 mm/memory.c:6580
 do_user_addr_fault+0x630/0x1080 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:618

read to 0xffff888237c27550 of 8 bytes by task 5054 on cpu 1:
 has_bh_in_lru+0x35/0x1f0 fs/buffer.c:1551
 smp_call_function_many_cond+0x2a9/0xc60 kernel/smp.c:821
 on_each_cpu_cond_mask+0x3c/0x80 kernel/smp.c:1043
 on_each_cpu_cond include/linux/smp.h:105 [inline]
 invalidate_bh_lrus+0x2a/0x30 fs/buffer.c:1560
 kill_bdev block/bdev.c:90 [inline]
 blkdev_flush_mapping+0x9a/0x1a0 block/bdev.c:729
 blkdev_put_whole block/bdev.c:736 [inline]
 bdev_release+0x2bf/0x3d0 block/bdev.c:1161
 blkdev_release+0x15/0x20 block/fops.c:706
 __fput+0x29b/0x650 fs/file_table.c:468
 ____fput+0x1c/0x30 fs/file_table.c:496
 task_work_run+0x131/0x1a0 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:44 [inline]
 exit_to_user_mode_loop+0x1fe/0x740 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x1ef/0x2c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff888107e63888 -> 0xffff8881007cc618

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 5054 Comm: syz-executor Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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