syzbot

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BUG: KCSAN: data-race in __folio_end_writeback / writeout_period

write to 0xffffffff87004360 of 8 bytes by interrupt on cpu 1:
 writeout_period+0xa6/0xe0 mm/page-writeback.c:611
 call_timer_fn+0x2e/0x240 kernel/time/timer.c:1421
 expire_timers+0x116/0x240 kernel/time/timer.c:1466
 __run_timers+0x368/0x410 kernel/time/timer.c:1734
 run_timer_softirq+0x56/0x60 kernel/time/timer.c:1749
 __do_softirq+0x158/0x2de kernel/softirq.c:558
 run_ksoftirqd+0x1f/0x30 kernel/softirq.c:921
 smpboot_thread_fn+0x308/0x4a0 kernel/smpboot.c:164
 kthread+0x1bf/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

read to 0xffffffff87004360 of 8 bytes by task 16833 on cpu 0:
 wb_domain_writeout_add mm/page-writeback.c:560 [inline]
 __wb_writeout_add mm/page-writeback.c:581 [inline]
 __folio_end_writeback+0x35e/0x630 mm/page-writeback.c:2811
 folio_end_writeback+0x57/0x130 mm/filemap.c:1655
 end_page_writeback+0x3b/0xe0 mm/folio-compat.c:26
 ext4_finish_bio+0x30e/0x3f0 fs/ext4/page-io.c:143
 ext4_release_io_end+0x5f/0x140 fs/ext4/page-io.c:158
 ext4_end_io_end fs/ext4/page-io.c:192 [inline]
 ext4_do_flush_completed_IO fs/ext4/page-io.c:257 [inline]
 ext4_end_io_rsv_work+0x1f6/0x240 fs/ext4/page-io.c:271
 process_one_work+0x3e3/0x970 kernel/workqueue.c:2289
 worker_thread+0x638/0xaa0 kernel/workqueue.c:2436
 kthread+0x1bf/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

value changed: 0x000000010000d0d2 -> 0x000000010000d1fe

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 16833 Comm: kworker/u4:9 Not tainted 5.17.0-syzkaller-07593-g52deda9551a0-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
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