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BUG: KCSAN: data-race in __folio_end_writeback / writeout_period

write to 0xffffffff84152490 of 8 bytes by interrupt on cpu 0:
 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:636 [inline]
 irq_exit_rcu+0x37/0x70 kernel/softirq.c:648
 sysvec_apic_timer_interrupt+0x8d/0xb0 arch/x86/kernel/apic/apic.c:1097
 asm_sysvec_apic_timer_interrupt+0x12/0x20
 __rcu_read_unlock+0x82/0x290 kernel/rcu/tree_plugin.h:429
 rcu_read_unlock include/linux/rcupdate.h:720 [inline]
 avc_has_perm_noaudit+0x1c0/0x270 security/selinux/avc.c:1163
 selinux_inode_permission+0x2da/0x3f0 security/selinux/hooks.c:3191
 security_inode_permission+0x72/0xc0 security/security.c:1314
 inode_permission fs/namei.c:532 [inline]
 may_lookup fs/namei.c:1683 [inline]
 link_path_walk+0x1e4/0x930 fs/namei.c:2239
 path_parentat fs/namei.c:2496 [inline]
 filename_parentat+0x123/0x480 fs/namei.c:2519
 do_unlinkat+0x83/0x540 fs/namei.c:4138
 __do_sys_unlink fs/namei.c:4215 [inline]
 __se_sys_unlink fs/namei.c:4213 [inline]
 __x64_sys_unlink+0x2c/0x30 fs/namei.c:4213
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffffffff84152490 of 8 bytes by task 516 on cpu 1:
 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:2814
 folio_end_writeback+0x58/0xd0 mm/filemap.c:1590
 end_page_writeback+0x37/0x50 mm/folio-compat.c:25
 ext4_finish_bio+0x3e2/0x430 fs/ext4/page-io.c:143
 ext4_release_io_end+0x98/0x200 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+0x306/0x360 fs/ext4/page-io.c:271
 process_one_work+0x3fc/0x980 kernel/workqueue.c:2298
 worker_thread+0x616/0xa70 kernel/workqueue.c:2445
 kthread+0x2c7/0x2e0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30

value changed: 0x0000000100008409 -> 0x0000000100008535

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 516 Comm: kworker/u4:5 Not tainted 5.15.0-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
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