INFO: rcu detected stall in kvm_vcpu_ioctl

Status: upstream: reported C repro on 2020/01/10 19:56
Reported-by: syzbot+fdc7ca10e5f338f55f79@syzkaller.appspotmail.com
First crash: 2404d, last: 1749d
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in kvm_vcpu_ioctl (2) kvm-x86 1 1 733d 733d 0/29 auto-obsoleted due to no activity on 2024/11/06 13:35
upstream INFO: rcu detected stall in kvm_vcpu_ioctl (4) prio:high kvm kvm-x86 1 syz, C error 8 4d13h 227d 1/29 upstream: reported C repro on 2025/12/27 03:34
upstream INFO: rcu detected stall in kvm_vcpu_ioctl (3) kvm-x86 1 2 528d 593d 0/29 auto-obsoleted due to no activity on 2025/05/30 15:19
upstream INFO: rcu detected stall in kvm_vcpu_ioctl mm 1 syz, C error unreliable 251 1714d 2891d 0/29 closed as invalid on 2022/02/08 10:48
linux-4.14 INFO: rcu detected stall in kvm_vcpu_ioctl 1 syz, C error 12 2305d 2463d 0/1 upstream: reported C repro on 2019/11/13 08:08
linux-5.15 INFO: rcu detected stall in kvm_vcpu_ioctl origin:lts-only 1 syz, C error 9 65d 431d 0/3 upstream: reported C repro on 2025/06/05 19:21
linux-4.19 BUG: soft lockup in kvm_vcpu_ioctl 1 syz, C error 2 1927d 1930d 0/1 upstream: reported C repro on 2021/04/28 21:34
android-5-15 BUG: soft lockup in kvm_vcpu_ioctl 1 1 849d 849d 0/2 auto-obsoleted due to no activity on 2024/07/12 20:15
▶ ▼ Fix bisection attempts (5)
Created Duration User Patch Repo Result
2020/10/13 21:27 4m bisect fix linux-4.19.y error job log
2020/09/13 19:50 29m bisect fix linux-4.19.y OK (0) job log log
2020/08/13 08:39 30m bisect fix linux-4.19.y OK (0) job log log
2020/06/17 20:16 29m bisect fix linux-4.19.y OK (0) job log log
2020/05/18 19:39 36m bisect fix linux-4.19.y OK (0) job log log

Sample crash report:
kvm: emulating exchange as write
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 1, t=10502 jiffies, g=7029, q=9)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295015275-4295004773), jiffies_till_next_fqs=1, root ->qsmask 0x0
syz-executor855 R  running task    28120  8454   8328 0x00000800
Call Trace:
 <IRQ>
 sched_show_task kernel/sched/core.c:5338 [inline]
 sched_show_task.cold+0x2e2/0x343 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+0xaf0/0xddc kernel/rcu/tree.c:2682
 update_process_times+0x2a/0x70 kernel/time/timer.c:1638
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:168
 tick_sched_timer+0x42/0x130 kernel/time/tick-sched.c:1278
 __run_hrtimer kernel/time/hrtimer.c:1401 [inline]
 __hrtimer_run_queues+0x2fc/0xd50 kernel/time/hrtimer.c:1463
 hrtimer_interrupt+0x312/0x770 kernel/time/hrtimer.c:1521
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1067 [inline]
 smp_apic_timer_interrupt+0x10c/0x550 arch/x86/kernel/apic/apic.c:1092
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893
 </IRQ>
RIP: 0010:vcpu_enter_guest+0xed3/0x5ed0 arch/x86/kvm/x86.c:7831
Code: ff df 48 c1 e8 03 80 3c 10 00 0f 85 cb 44 00 00 48 83 3d 67 2f a6 07 00 0f 84 c0 36 00 00 e8 84 71 5b 00 fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 13 73 3a 00 65 8b 1d 7c c6 f5 7e 31 ff 89 de e8
RSP: 0018:ffff88809fa37a30 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13
RAX: ffff88809f51e540 RBX: ffff88809f51e540 RCX: 1ffff11013ea3dbc
RDX: 0000000000000000 RSI: ffffffff810c273c RDI: ffff88809f51edbc
RBP: ffff88809fa37b40 R08: ffff88809f51e540 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880a4f306c0
R13: ffff8880a4f306ec R14: fffffe92e03ed1ee R15: 0000000000000000
 vcpu_run arch/x86/kvm/x86.c:7913 [inline]
 kvm_arch_vcpu_ioctl_run+0x446/0x16a0 arch/x86/kvm/x86.c:8113
 kvm_vcpu_ioctl+0x493/0xe20 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2667
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcda/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x44a9e9
Code: e8 ec e7 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 1b ff fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f0d0e1e4ce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000006dfc58 RCX: 000000000044a9e9
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000008
RBP: 00000000006dfc50 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dfc5c
R13: 00007ffec2d9748f R14: 00007f0d0e1e59c0 R15: 0000000000000005
rcu: rcu_preempt kthread starved for 10502 jiffies! g7029 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    29152    10      2 0x80000000
Call Trace:
 schedule+0x8d/0x1b0 kernel/sched/core.c:3559
 schedule_timeout+0x4d1/0xf20 kernel/time/timer.c:1806
 rcu_gp_kthread+0xcee/0x2060 kernel/rcu/tree.c:2202
 kthread+0x34a/0x420 kernel/kthread.c:246
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

Crashes (46):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/03/01 17:44 linux-4.19.y a083db76118d c88c7b75 .config console log report syz C ci2-linux-4-19
2021/10/27 15:37 linux-4.19.y 3f8a27f9e27b be531bb4 .config console log report info ci2-linux-4-19 INFO: rcu detected stall in kvm_vcpu_ioctl
2020/08/14 19:50 linux-4.19.y c14d30dc9987 5ce13532 .config console log report ci2-linux-4-19
2020/07/14 08:39 linux-4.19.y dce0f88600e4 ce4c95b3 .config console log report ci2-linux-4-19
2020/07/03 05:24 linux-4.19.y 399849e4654e f30c14bf .config console log report ci2-linux-4-19
2020/04/18 19:15 linux-4.19.y 8488c3f3bc86 365fba24 .config console log report ci2-linux-4-19
2020/04/13 20:46 linux-4.19.y 6dd0e32665e5 17a986e5 .config console log report ci2-linux-4-19
2020/04/12 08:30 linux-4.19.y dda0e2920330 a8c6a3f8 .config console log report ci2-linux-4-19
2020/04/09 13:15 linux-4.19.y dda0e2920330 a8c6a3f8 .config console log report ci2-linux-4-19
2020/04/08 07:59 linux-4.19.y dda0e2920330 db9bcd4b .config console log report ci2-linux-4-19
2020/04/03 01:26 linux-4.19.y dda0e2920330 a34e2c33 .config console log report ci2-linux-4-19
2020/04/02 20:22 linux-4.19.y dda0e2920330 a34e2c33 .config console log report ci2-linux-4-19
2020/04/02 02:22 linux-4.19.y 54b4fa6d3955 a34e2c33 .config console log report ci2-linux-4-19
2020/04/01 19:58 linux-4.19.y 54b4fa6d3955 a34e2c33 .config console log report ci2-linux-4-19
2020/04/01 17:19 linux-4.19.y 54b4fa6d3955 a34e2c33 .config console log report ci2-linux-4-19
2020/03/31 07:37 linux-4.19.y 54b4fa6d3955 c8d1cc20 .config console log report ci2-linux-4-19
2020/03/30 18:47 linux-4.19.y 54b4fa6d3955 c8d1cc20 .config console log report ci2-linux-4-19
2020/03/30 04:29 linux-4.19.y 54b4fa6d3955 05736b29 .config console log report ci2-linux-4-19
2020/03/28 03:41 linux-4.19.y 54b4fa6d3955 831e9a81 .config console log report ci2-linux-4-19
2020/03/24 13:48 linux-4.19.y 14cfdbd39e31 33e14df3 .config console log report ci2-linux-4-19
2020/03/23 16:25 linux-4.19.y 14cfdbd39e31 84f999d6 .config console log report ci2-linux-4-19
2020/03/23 10:02 linux-4.19.y 14cfdbd39e31 78267cec .config console log report ci2-linux-4-19
2020/03/20 09:06 linux-4.19.y 93556fb211fa 2c31c529 .config console log report ci2-linux-4-19
2020/03/20 02:10 linux-4.19.y 93556fb211fa 2c31c529 .config console log report ci2-linux-4-19
2020/03/19 07:23 linux-4.19.y 93556fb211fa 2c31c529 .config console log report ci2-linux-4-19
2020/03/16 07:18 linux-4.19.y 569209711609 749688d2 .config console log report ci2-linux-4-19
2020/03/16 00:00 linux-4.19.y 569209711609 749688d2 .config console log report ci2-linux-4-19
2020/03/15 22:19 linux-4.19.y 569209711609 749688d2 .config console log report ci2-linux-4-19
2020/03/13 10:48 linux-4.19.y 569209711609 fd69032d .config console log report ci2-linux-4-19
2020/03/12 21:13 linux-4.19.y 569209711609 d850e9d0 .config console log report ci2-linux-4-19
2020/03/11 13:26 linux-4.19.y 7472c4028e23 e103bc9e .config console log report ci2-linux-4-19
2020/03/11 11:12 linux-4.19.y 7472c4028e23 e103bc9e .config console log report ci2-linux-4-19
2020/03/10 20:14 linux-4.19.y 7472c4028e23 35f53e45 .config console log report ci2-linux-4-19
2020/03/09 17:30 linux-4.19.y 7472c4028e23 35f53e45 .config console log report ci2-linux-4-19
2020/03/08 03:47 linux-4.19.y 7472c4028e23 2e9971bb .config console log report ci2-linux-4-19
2020/03/07 05:38 linux-4.19.y 7472c4028e23 fd2a5f28 .config console log report ci2-linux-4-19
2020/03/04 02:23 linux-4.19.y a083db76118d 1f73b64b .config console log report ci2-linux-4-19
2020/03/03 07:10 linux-4.19.y a083db76118d 4a4e0509 .config console log report ci2-linux-4-19
2020/03/03 06:26 linux-4.19.y a083db76118d 4a4e0509 .config console log report ci2-linux-4-19
2020/03/03 05:37 linux-4.19.y a083db76118d 4a4e0509 .config console log report ci2-linux-4-19
2020/03/03 01:04 linux-4.19.y a083db76118d 4a4e0509 .config console log report ci2-linux-4-19
2020/03/02 09:01 linux-4.19.y a083db76118d 4a4e0509 .config console log report ci2-linux-4-19
2020/03/02 08:40 linux-4.19.y a083db76118d 4a4e0509 .config console log report ci2-linux-4-19
2020/03/01 14:50 linux-4.19.y a083db76118d c88c7b75 .config console log report ci2-linux-4-19
2020/02/29 14:28 linux-4.19.y a083db76118d c88c7b75 .config console log report ci2-linux-4-19
2020/01/10 19:55 linux-4.19.y cb1f9a169a0e 532ec44e .config console log report ci2-linux-4-19
* Struck through repros no longer work on HEAD.