================================================================== BUG: KCSAN: data-race in fprop_new_period / fprop_reflect_period_percpu read-write to 0xffffffff8830b820 of 4 bytes by interrupt on cpu 0: fprop_new_period+0xd7/0x130 lib/flex_proportions.c:83 writeout_period+0x55/0xe0 mm/page-writeback.c:628 call_timer_fn+0x2e/0x240 kernel/time/timer.c:1410 expire_timers+0x116/0x260 kernel/time/timer.c:1455 __run_timers+0x328/0x3c0 kernel/time/timer.c:1747 run_timer_softirq+0x2d/0x30 kernel/time/timer.c:1762 __do_softirq+0x12c/0x2b1 kernel/softirq.c:298 asm_call_irq_on_stack+0xf/0x20 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline] do_softirq_own_stack+0x32/0x40 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:393 [inline] __irq_exit_rcu+0xb2/0xc0 kernel/softirq.c:423 sysvec_apic_timer_interrupt+0x74/0x90 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631 native_restore_fl arch/x86/include/asm/irqflags.h:41 [inline] arch_local_irq_restore arch/x86/include/asm/irqflags.h:84 [inline] kcsan_setup_watchpoint+0x1ec/0x4d0 kernel/kcsan/core.c:591 tomoyo_check_acl+0x9a/0x200 security/tomoyo/domain.c:173 tomoyo_path_permission security/tomoyo/file.c:586 [inline] tomoyo_path_perm+0x22f/0x330 security/tomoyo/file.c:838 tomoyo_inode_getattr+0x18/0x20 security/tomoyo/tomoyo.c:123 security_inode_getattr+0x7f/0xd0 security/security.c:1279 vfs_getattr fs/stat.c:121 [inline] vfs_fstat+0x45/0x390 fs/stat.c:146 __do_sys_newfstat fs/stat.c:386 [inline] __se_sys_newfstat+0x35/0x240 fs/stat.c:383 __x64_sys_newfstat+0x2d/0x40 fs/stat.c:383 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffffffff8830b820 of 4 bytes by task 3042 on cpu 1: fprop_reflect_period_percpu+0x22/0x1a0 lib/flex_proportions.c:192 __fprop_inc_percpu+0x1a/0x80 lib/flex_proportions.c:222 __fprop_inc_percpu_max+0x3f/0x190 lib/flex_proportions.c:271 wb_domain_writeout_inc mm/page-writeback.c:575 [inline] __wb_writeout_inc+0x54/0x1a0 mm/page-writeback.c:599 test_clear_page_writeback+0x2fa/0x450 mm/page-writeback.c:2745 end_page_writeback+0xa7/0x110 mm/filemap.c:1487 ext4_finish_bio+0x429/0x490 fs/ext4/page-io.c:146 ext4_release_io_end+0x98/0x200 fs/ext4/page-io.c:161 ext4_end_io_end fs/ext4/page-io.c:195 [inline] ext4_do_flush_completed_IO fs/ext4/page-io.c:260 [inline] ext4_end_io_rsv_work+0x306/0x360 fs/ext4/page-io.c:274 process_one_work+0x3e1/0x950 kernel/workqueue.c:2272 worker_thread+0x635/0xb90 kernel/workqueue.c:2418 kthread+0x1fa/0x220 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 3042 Comm: kworker/u4:4 Not tainted 5.10.0-rc4-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 ==================================================================