syzbot

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BUG: KCSAN: data-race in __mark_inode_dirty / move_expired_inodes

write to 0xffff8881017e25a8 of 8 bytes by task 1790 on cpu 1:
 move_expired_inodes+0x1ca/0x4c0 fs/fs-writeback.c:1403
 queue_io+0xe1/0x270 fs/fs-writeback.c:1450
 wb_writeback+0x265/0x700 fs/fs-writeback.c:2049
 wb_check_start_all fs/fs-writeback.c:2177 [inline]
 wb_do_writeback+0x330/0x510 fs/fs-writeback.c:2203
 wb_workfn+0xc8/0x520 fs/fs-writeback.c:2237
 process_one_work+0x3e9/0x8f0 kernel/workqueue.c:2276
 worker_thread+0x636/0xae0 kernel/workqueue.c:2422
 kthread+0x262/0x280 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

read to 0xffff8881017e25a8 of 8 bytes by task 7570 on cpu 0:
 __mark_inode_dirty+0xda/0x680 fs/fs-writeback.c:2419
 mark_buffer_dirty+0x143/0x200 fs/buffer.c:1112
 __ext4_handle_dirty_metadata+0x20c/0x590 fs/ext4/ext4_jbd2.c:359
 ext4_do_update_inode fs/ext4/inode.c:5139 [inline]
 ext4_mark_iloc_dirty+0x1306/0x1750 fs/ext4/inode.c:5724
 __ext4_mark_inode_dirty+0x4db/0x5b0 fs/ext4/inode.c:5918
 ext4_dirty_inode+0x86/0xa0 fs/ext4/inode.c:5947
 __mark_inode_dirty+0x77/0x680 fs/fs-writeback.c:2398
 generic_update_time fs/inode.c:1772 [inline]
 update_time fs/inode.c:1785 [inline]
 file_update_time+0x3a4/0x3e0 fs/inode.c:2001
 ext4_page_mkwrite+0x11b/0xed0 fs/ext4/inode.c:6064
 do_page_mkwrite mm/memory.c:2870 [inline]
 do_shared_fault mm/memory.c:4236 [inline]
 do_fault mm/memory.c:4304 [inline]
 handle_pte_fault mm/memory.c:4558 [inline]
 __handle_mm_fault mm/memory.c:4693 [inline]
 handle_mm_fault+0x1089/0x1a50 mm/memory.c:4791
 do_user_addr_fault+0x609/0xbe0 arch/x86/mm/fault.c:1390
 handle_page_fault arch/x86/mm/fault.c:1475 [inline]
 exc_page_fault+0x91/0x220 arch/x86/mm/fault.c:1531
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:568

value changed: 0x0000000000000004 -> 0x0000000000020084

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7570 Comm: syz-executor.0 Not tainted 5.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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