syzbot

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BUG: KCSAN: data-race in __mark_inode_dirty / __writeback_single_inode

read-write to 0xffff8881005eea38 of 4 bytes by task 37 on cpu 1:
 __writeback_single_inode+0x1f4/0x850 fs/fs-writeback.c:1716
 writeback_sb_inodes+0x461/0xa30 fs/fs-writeback.c:1976
 wb_writeback+0x262/0x640 fs/fs-writeback.c:2156
 wb_do_writeback fs/fs-writeback.c:2303 [inline]
 wb_workfn+0x1a8/0x940 fs/fs-writeback.c:2343
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4db/0xa20 kernel/workqueue.c:3319
 worker_thread+0x51d/0x6f0 kernel/workqueue.c:3400
 kthread+0x4ae/0x520 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

read to 0xffff8881005eea38 of 4 bytes by task 27921 on cpu 0:
 __mark_inode_dirty+0x198/0x7e0 fs/fs-writeback.c:2537
 mark_buffer_dirty+0x149/0x230 fs/buffer.c:1199
 __block_commit_write fs/buffer.c:2189 [inline]
 block_page_mkwrite+0x29c/0x3f0 fs/buffer.c:2633
 ext4_page_mkwrite+0x73d/0xb70 fs/ext4/inode.c:6181
 do_page_mkwrite mm/memory.c:3257 [inline]
 wp_page_shared mm/memory.c:3658 [inline]
 do_wp_page+0xca1/0x2340 mm/memory.c:3808
 handle_pte_fault mm/memory.c:5923 [inline]
 __handle_mm_fault mm/memory.c:6050 [inline]
 handle_mm_fault+0xc63/0x2ac0 mm/memory.c:6219
 do_user_addr_fault arch/x86/mm/fault.c:1337 [inline]
 handle_page_fault arch/x86/mm/fault.c:1480 [inline]
 exc_page_fault+0x3b9/0x650 arch/x86/mm/fault.c:1538
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

value changed: 0x0001002a -> 0x00000022

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 27921 Comm: syz.5.7368 Not tainted 6.14.0-rc6-syzkaller-00103-g4003c9e78778 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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