syzbot


INFO: rcu detected stall in chrdev_open

Status: auto-closed as invalid on 2020/05/02 02:53
Reported-by: syzbot+811771edb3c20aaa1c86@syzkaller.appspotmail.com
First crash: 998d, last: 998d
similar bugs (5):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: rcu detected stall in chrdev_open (2) 1 864d 864d 0/1 auto-closed as invalid on 2020/09/12 23:19
linux-4.14 INFO: rcu detected stall in chrdev_open C error 4 174d 280d 0/1 upstream: reported C repro on 2021/12/21 07:54
linux-4.19 INFO: rcu detected stall in chrdev_open (3) C error 16 173d 553d 0/1 upstream: reported C repro on 2021/03/22 19:09
upstream INFO: rcu detected stall in chrdev_open (2) C done inconclusive 55 252d 1019d 0/24 closed as invalid on 2022/02/08 10:45
upstream INFO: rcu detected stall in chrdev_open 4 1028d 1029d 0/24 closed as invalid on 2019/12/04 14:04

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 0, t=10502 jiffies, g=273229, q=31)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295085511-4295075009), jiffies_till_next_fqs=1, root ->qsmask 0x0
syz-executor.0  R  running task    26784  5439   7743 0x00000000
Call Trace:
 <IRQ>
 sched_show_task kernel/sched/core.c:5338 [inline]
 sched_show_task.cold+0x2ee/0x35d kernel/sched/core.c:5313
 print_other_cpu_stall kernel/rcu/tree.c:1430 [inline]
 check_cpu_stall kernel/rcu/tree.c:1557 [inline]
 __rcu_pending kernel/rcu/tree.c:3293 [inline]
 rcu_pending kernel/rcu/tree.c:3336 [inline]
 rcu_check_callbacks.cold+0xaa1/0xd90 kernel/rcu/tree.c:2682
 update_process_times+0x32/0x80 kernel/time/timer.c:1638
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:164
 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1274
 __run_hrtimer kernel/time/hrtimer.c:1398 [inline]
 __hrtimer_run_queues+0x33b/0xdc0 kernel/time/hrtimer.c:1460
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1518
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1067 [inline]
 smp_apic_timer_interrupt+0x111/0x550 arch/x86/kernel/apic/apic.c:1092
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893
 </IRQ>
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x54/0x90 kernel/locking/spinlock.c:192
Code: c0 d8 5b f2 88 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 33 48 83 3d 4d ff a5 01 00 74 20 fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 22 b4 fc f9 65 8b 05 2b 91 b5 78 85 c0 74 06 41
RSP: 0018:ffff88809fab7718 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff11e4b7b RBX: ffff888095934b60 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff888095934dbc
RBP: ffff88809fab7720 R08: ffff888095934540 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880ae82c240
R13: ffffffff87aa96a0 R14: ffff888095934540 R15: ffff8880ae82c240
 rq_unlock_irq kernel/sched/sched.h:1842 [inline]
 __schedule+0x1495/0x1dc0 kernel/sched/core.c:3518
 schedule+0x92/0x1c0 kernel/sched/core.c:3559
 tty_open+0x765/0xb70 drivers/tty/tty_io.c:2036
 chrdev_open+0x245/0x6b0 fs/char_dev.c:423
 do_dentry_open+0x4c3/0x1210 fs/open.c:796
 vfs_open+0xa0/0xd0 fs/open.c:905
 do_last fs/namei.c:3418 [inline]
 path_openat+0x10d7/0x45e0 fs/namei.c:3534
 do_filp_open+0x1a1/0x280 fs/namei.c:3564
 do_sys_open+0x3fe/0x550 fs/open.c:1088
 __do_sys_openat fs/open.c:1115 [inline]
 __se_sys_openat fs/open.c:1109 [inline]
 __x64_sys_openat+0x9d/0x100 fs/open.c:1109
 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45a9e9
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f6a76257c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045a9e9
RDX: 0000000000000000 RSI: 0000000020000240 RDI: ffffffffffffff9c
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6a762586d4
R13: 00000000004c87ee R14: 00000000004e0018 R15: 00000000ffffffff
rcu: rcu_preempt kthread starved for 10502 jiffies! g273229 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    29104    10      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2826 [inline]
 __schedule+0x866/0x1dc0 kernel/sched/core.c:3515
 schedule+0x92/0x1c0 kernel/sched/core.c:3559
 schedule_timeout+0x4db/0xfc0 kernel/time/timer.c:1806
 rcu_gp_kthread+0xd5c/0x2190 kernel/rcu/tree.c:2202
 kthread+0x354/0x420 kernel/kthread.c:246
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-19 2020/01/03 02:52 linux-4.19.y c7ecf3e3a71c 25a0186e .config log report
* Struck through repros no longer work on HEAD.