FAT-fs (loop4): Invalid FSINFO signature: 0x00000000, 0x00000000 (sector = 1)
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BUG: KCSAN: data-race in wb_timer_fn / wbt_wait

write to 0xffff88821a246104 of 4 bytes by interrupt on cpu 1:
 calc_wb_limits block/blk-wbt.c:304 [inline]
 scale_up block/blk-wbt.c:313 [inline]
 wb_timer_fn+0x42d/0xa40 block/blk-wbt.c:382
 blk_stat_timer_fn+0x3f4/0x410 block/blk-stat.c:99
 call_timer_fn+0x30/0x2a0 kernel/time/timer.c:1413
 expire_timers+0x116/0x290 kernel/time/timer.c:1458
 __run_timers+0x348/0x3e0 kernel/time/timer.c:1755
 run_timer_softirq+0x2e/0x60 kernel/time/timer.c:1768
 __do_softirq+0x198/0x360 kernel/softirq.c:298
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 do_softirq_own_stack+0x5d/0x80 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:393 [inline]
 __irq_exit_rcu+0x115/0x120 kernel/softirq.c:423
 sysvec_apic_timer_interrupt+0xba/0xd0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581
 arch_local_irq_restore arch/x86/include/asm/paravirt.h:770 [inline]
 kcsan_setup_watchpoint+0x44b/0x4a0 kernel/kcsan/core.c:563
 tomoyo_compare_number_union security/tomoyo/file.c:117 [inline]
 tomoyo_check_path_number_acl+0xc5/0x160 security/tomoyo/file.c:282
 tomoyo_check_acl+0xcc/0x220 security/tomoyo/domain.c:175
 tomoyo_path_number_perm+0x1af/0x2d0 security/tomoyo/file.c:733
 tomoyo_path_chmod+0x23/0x30 security/tomoyo/tomoyo.c:342
 security_path_chmod+0x92/0xe0 security/security.c:1151
 chmod_common+0xe6/0x280 fs/open.c:578
 vfs_fchmod fs/open.c:598 [inline]
 __do_sys_fchmod fs/open.c:607 [inline]
 __se_sys_fchmod fs/open.c:601 [inline]
 __x64_sys_fchmod+0xac/0xf0 fs/open.c:601
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88821a246104 of 4 bytes by task 7 on cpu 0:
 rwb_enabled block/blk-wbt.c:80 [inline]
 bio_to_wbt_flags block/blk-wbt.c:543 [inline]
 wbt_wait+0x36/0x2b0 block/blk-wbt.c:576
 __rq_qos_throttle+0x39/0x70 block/blk-rq-qos.c:72
 rq_qos_throttle block/blk-rq-qos.h:182 [inline]
 blk_mq_submit_bio+0x244/0x1130 block/blk-mq.c:2168
 __submit_bio_noacct_mq block/blk-core.c:1180 [inline]
 submit_bio_noacct+0x772/0x950 block/blk-core.c:1213
 submit_bio+0x200/0x370 block/blk-core.c:1283
 mpage_bio_submit fs/mpage.c:66 [inline]
 __mpage_writepage+0xbc3/0x1070 fs/mpage.c:637
 write_cache_pages+0x4cb/0x840 mm/page-writeback.c:2246
 mpage_writepages+0x6d/0x120 fs/mpage.c:714
 fat_writepages+0x20/0x30 fs/fat/inode.c:205
 do_writepages+0x7b/0x150 mm/page-writeback.c:2352
 __writeback_single_inode+0x84/0x600 fs/fs-writeback.c:1461
 writeback_sb_inodes+0x6c0/0xff0 fs/fs-writeback.c:1721
 wb_writeback+0x28d/0x6f0 fs/fs-writeback.c:1894
 wb_do_writeback+0x101/0x5f0 fs/fs-writeback.c:2039
 wb_workfn+0xc8/0x470 fs/fs-writeback.c:2080
 process_one_work+0x3e1/0x9a0 kernel/workqueue.c:2269
 worker_thread+0x665/0xbe0 kernel/workqueue.c:2415
 kthread+0x20d/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7 Comm: kworker/u4:0 Not tainted 5.9.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: writeback wb_workfn (flush-7:4)
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