syzbot


INFO: rcu detected stall in __do_softirq

Status: auto-closed as invalid on 2019/12/20 09:57
Reported-by: syzbot+ea09550fd283be3329bf@syzkaller.appspotmail.com
First crash: 1259d, last: 1194d
similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: rcu detected stall in __do_softirq (2) 9 807d 992d 0/1 auto-closed as invalid on 2021/01/10 17:25
linux-4.14 INFO: rcu detected stall in __do_softirq 1 1259d 1259d 0/1 auto-closed as invalid on 2019/10/25 08:47
upstream INFO: rcu detected stall in __do_softirq syz done 34 415d 1211d 0/24 upstream: reported syz repro on 2019/08/05 15:28

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 1, t=30025 jiffies, g=57045, q=389)
rcu: All QSes seen, last rcu_preempt kthread activity 30025 (4295005994-4294975969), jiffies_till_next_fqs=1, root ->qsmask 0x0
syz-executor.4  R  running task    28088 20573   7495 0x00000008
Call Trace:
 <IRQ>
 sched_show_task kernel/sched/core.c:5297 [inline]
 sched_show_task.cold+0x2ee/0x35d kernel/sched/core.c:5272
 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:1636
 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:1029 [inline]
 smp_apic_timer_interrupt+0x111/0x550 arch/x86/kernel/apic/apic.c:1054
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893
RIP: 0010:ffs arch/x86/include/asm/bitops.h:416 [inline]
RIP: 0010:__do_softirq+0x227/0x921 kernel/softirq.c:280
Code: c7 c0 d8 44 72 88 48 c1 e8 03 42 80 3c 38 00 0f 85 a7 06 00 00 48 83 3d be 42 52 01 00 0f 84 bb 05 00 00 fb 66 0f 1f 44 00 00 <b8> ff ff ff ff 48 c7 45 c8 00 91 60 88 0f bc 45 d4 83 c0 01 89 45
RSP: 0018:ffff8880ae907f10 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff10e489b RBX: ffff88805c176440 RCX: 1ffff1100b82ed9c
RDX: 0000000000000000 RSI: ffff88805c176ce8 RDI: ffff88805c176cbc
RBP: ffff8880ae907f98 R08: ffff88805c176440 R09: ffff88805c176ce0
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88808de97968
R13: 0000000000000027 R14: 0000000000000027 R15: dffffc0000000000
 invoke_softirq kernel/softirq.c:372 [inline]
 irq_exit+0x180/0x1d0 kernel/softirq.c:412
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 do_IRQ+0x113/0x1d0 arch/x86/kernel/irq.c:258
 common_interrupt+0xf/0xf arch/x86/entry/entry_64.S:670
 </IRQ>
RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:23 [inline]
RIP: 0010:static_key_false include/linux/jump_label.h:138 [inline]
RIP: 0010:lapic_in_kernel arch/x86/kvm/lapic.h:159 [inline]
RIP: 0010:kvm_apic_present arch/x86/kvm/lapic.h:184 [inline]
RIP: 0010:kvm_lapic_enabled arch/x86/kvm/lapic.h:189 [inline]
RIP: 0010:vcpu_enter_guest+0x258f/0x6120 arch/x86/kvm/x86.c:7594
Code: c8 7f 08 84 c0 0f 85 9f 31 00 00 41 0f b6 9c 24 44 2c 00 00 31 ff 89 de e8 4e ce 5e 00 84 db 0f 85 08 7e 01 00 e8 01 cd 5e 00 <e9> 9b 04 00 00 e8 f7 cc 5e 00 49 8d bc 24 e0 03 00 00 48 b8 00 00
RSP: 0018:ffff88808de97a10 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffd8
RAX: 0000000000040000 RBX: 0000000000000000 RCX: ffffc9000e6c3000
RDX: 0000000000040000 RSI: ffffffff810c922f RDI: 0000000000000001
RBP: ffff88808de97b20 R08: ffff88805c176440 R09: 0000000000000001
R10: ffff88808de97b38 R11: 00000000c89a0c80 R12: ffff888054be1680
R13: ffff888054be5b04 R14: 0000000000000000 R15: ffff888054be16b0
 vcpu_run arch/x86/kvm/x86.c:7798 [inline]
 kvm_arch_vcpu_ioctl_run+0x457/0x16b0 arch/x86/kvm/x86.c:7998
 kvm_vcpu_ioctl+0x4dc/0xf90 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2617
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xd5f/0x1380 fs/ioctl.c:688
 ksys_ioctl+0xab/0xd0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:710
 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459829
Code: fd b7 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f019ea61c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459829
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000009
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f019ea626d4
R13: 00000000004c2bcf R14: 00000000004d6210 R15: 00000000ffffffff
rcu: rcu_preempt kthread starved for 30025 jiffies! g57045 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    29024    10      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2826 [inline]
 __schedule+0x866/0x1dc0 kernel/sched/core.c:3474
 schedule+0x92/0x1c0 kernel/sched/core.c:3518
 schedule_timeout+0x4db/0xfc0 kernel/time/timer.c:1804
 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 (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-19 2019/08/22 09:57 linux-4.19.y a5aa80588fcd 4ea67ff8 .config log report
ci2-linux-4-19 2019/06/18 23:12 linux-4.19.y 6500aa436df4 34bf9440 .config log report
* Struck through repros no longer work on HEAD.