==================================================================
BUG: KCSAN: data-race in __folio_end_writeback / writeout_period

write to 0xffffffff86dda330 of 8 bytes by interrupt on cpu 1:
 writeout_period+0xa6/0xe0 mm/page-writeback.c:623
 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
 __irq_exit_rcu kernel/softirq.c:637 [inline]
 irq_exit_rcu+0x37/0x70 kernel/softirq.c:649
 sysvec_apic_timer_interrupt+0x8d/0xb0 arch/x86/kernel/apic/apic.c:1097
 asm_sysvec_apic_timer_interrupt+0x12/0x20
 kcsan_setup_watchpoint+0x43d/0x460 kernel/kcsan/core.c:694
 xas_start lib/xarray.c:188 [inline]
 xas_load+0xc6/0x2a0 lib/xarray.c:233
 filemap_get_read_batch+0x7b/0x410 mm/filemap.c:2350
 filemap_get_pages mm/filemap.c:2552 [inline]
 filemap_read+0x34b/0x16d0 mm/filemap.c:2642
 generic_file_read_iter+0x72/0x2a0 mm/filemap.c:2792
 call_read_iter include/linux/fs.h:2156 [inline]
 generic_file_splice_read+0x24f/0x330 fs/splice.c:311
 do_splice_to fs/splice.c:796 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:870
 do_splice_direct+0x106/0x190 fs/splice.c:979
 do_sendfile+0x675/0xc40 fs/read_write.c:1245
 __do_sys_sendfile64 fs/read_write.c:1310 [inline]
 __se_sys_sendfile64 fs/read_write.c:1296 [inline]
 __x64_sys_sendfile64+0x102/0x140 fs/read_write.c:1296
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffffffff86dda330 of 8 bytes by task 43 on cpu 0:
 wb_domain_writeout_add mm/page-writeback.c:572 [inline]
 __wb_writeout_add mm/page-writeback.c:593 [inline]
 __folio_end_writeback+0x2b3/0x580 mm/page-writeback.c:2821
 folio_end_writeback+0x57/0x130 mm/filemap.c:1605
 end_page_writeback+0x37/0x50 mm/folio-compat.c:25
 ext4_finish_bio+0x30e/0x360 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+0x3f6/0x960 kernel/workqueue.c:2307
 worker_thread+0x616/0xa70 kernel/workqueue.c:2454
 kthread+0x2c7/0x2e0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30

value changed: 0x00000000ffffcdc5 -> 0x00000000ffffcef1

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 43 Comm: kworker/u4:2 Not tainted 5.16.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
==================================================================