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BUG: KCSAN: data-race in __mark_inode_dirty / __writeback_single_inode

read-write to 0xffff8881072335c0 of 4 bytes by task 4380 on cpu 1:
 __writeback_single_inode+0x1e3/0x7c0 fs/fs-writeback.c:1755
 writeback_sb_inodes+0x48f/0xa30 fs/fs-writeback.c:2015
 __writeback_inodes_wb+0x94/0x1a0 fs/fs-writeback.c:2086
 wb_writeback+0x266/0x5c0 fs/fs-writeback.c:2197
 wb_check_start_all fs/fs-writeback.c:2323 [inline]
 wb_do_writeback fs/fs-writeback.c:2349 [inline]
 wb_workfn+0x4c9/0x910 fs/fs-writeback.c:2382
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3346
 worker_thread+0x582/0x770 kernel/workqueue.c:3427
 kthread+0x486/0x510 kernel/kthread.c:463
 ret_from_fork+0x11f/0x1b0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff8881072335c0 of 4 bytes by task 8090 on cpu 0:
 __mark_inode_dirty+0x191/0x750 fs/fs-writeback.c:2588
 generic_update_time fs/inode.c:2105 [inline]
 inode_update_time fs/inode.c:2118 [inline]
 __file_update_time fs/inode.c:2345 [inline]
 file_update_time+0x288/0x2b0 fs/inode.c:2375
 ext4_page_mkwrite+0x18c/0xb90 fs/ext4/inode.c:6675
 do_page_mkwrite mm/memory.c:3488 [inline]
 do_shared_fault mm/memory.c:5774 [inline]
 do_fault mm/memory.c:5836 [inline]
 do_pte_missing mm/memory.c:4361 [inline]
 handle_pte_fault mm/memory.c:6177 [inline]
 __handle_mm_fault mm/memory.c:6318 [inline]
 handle_mm_fault+0x15cb/0x2be0 mm/memory.c:6487
 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:623

value changed: 0x00020052 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 8090 Comm: syz.1.1840 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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