syzbot

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BUG: KCSAN: data-race in __mark_inode_dirty / redirty_tail_locked

read-write to 0xffff888106e58a50 of 4 bytes by task 4738 on cpu 1:
 redirty_tail_locked+0x56/0x280 fs/fs-writeback.c:1412
 requeue_inode fs/fs-writeback.c:-1 [inline]
 writeback_sb_inodes+0x72c/0xa30 fs/fs-writeback.c:2044
 wb_writeback+0x252/0x5c0 fs/fs-writeback.c:2195
 wb_do_writeback fs/fs-writeback.c:2342 [inline]
 wb_workfn+0x194/0x910 fs/fs-writeback.c:2382
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3346
 worker_thread+0x582/0x770 kernel/workqueue.c:3427
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x122/0x1b0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff888106e58a50 of 4 bytes by task 3304 on cpu 0:
 __mark_inode_dirty+0x191/0x750 fs/fs-writeback.c:2588
 mark_buffer_dirty+0x133/0x210 fs/buffer.c:1209
 block_commit_write fs/buffer.c:2218 [inline]
 block_page_mkwrite+0x287/0x3d0 fs/buffer.c:2643
 ext4_page_mkwrite+0x859/0xb90 fs/ext4/inode.c:6704
 do_page_mkwrite mm/memory.c:3489 [inline]
 wp_page_shared mm/memory.c:3890 [inline]
 do_wp_page+0xa77/0x2510 mm/memory.c:4109
 handle_pte_fault mm/memory.c:6211 [inline]
 __handle_mm_fault mm/memory.c:6336 [inline]
 handle_mm_fault+0x77d/0x2be0 mm/memory.c:6505
 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

value changed: 0x00020042 -> 0x00000040

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3304 Comm: syz-executor Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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