syzbot

 sign-in | mailing list | source | docs
🐞 Open [1594]
≡ Subsystems
🐞 Fixed [6235]
🐞 Invalid [15804]
⬇ Missing Backports [184]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
Total Repo Heatmap Subsystems Heatmap
💬 Send us feedback

INFO: rcu detected stall in schedule_tail (4)

Status: auto-obsoleted due to no activity on 2023/09/05 02:08
Subsystems: arm
[Documentation on labels]
First crash: 792d, last: 714d
▶ ▼ Similar bugs (6)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in schedule_tail 1 312d 312d 0/3 auto-obsoleted due to no activity on 2024/10/21 04:18
upstream INFO: rcu detected stall in schedule_tail kernel 145 1995d 1997d 0/28 closed as invalid on 2019/12/04 14:14
upstream INFO: rcu detected stall in schedule_tail (3) cgroups mm 40 1960d 1960d 0/28 closed as invalid on 2020/01/09 08:13
upstream INFO: rcu detected stall in schedule_tail (5) mm 2 586d 587d 0/28 auto-obsoleted due to no activity on 2024/01/11 06:31
upstream INFO: rcu detected stall in schedule_tail (6) mm C 8 135d 230d 0/28 auto-obsoleted due to no activity on 2025/04/16 03:50
upstream INFO: rcu detected stall in schedule_tail (2) kernel 26 1960d 1960d 0/28 closed as invalid on 2020/01/08 05:23

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5326/1:b..l
rcu: 	(detected by 1, t=10504 jiffies, g=27681, q=44 ncpus=2)
task:syz-fuzzer      state:R  running task     stack:22600 pid:5326  ppid:5062   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5304 [inline]
 __schedule+0x173b/0x4630 kernel/sched/core.c:6622
 preempt_schedule_common+0x83/0xc0 kernel/sched/core.c:6791
 preempt_schedule+0xdd/0xf0 kernel/sched/core.c:6815
 preempt_schedule_thunk+0x1a/0x20 arch/x86/entry/thunk_64.S:34
 __local_bh_enable_ip+0x179/0x1f0 kernel/softirq.c:403
 rcu_read_unlock_bh include/linux/rcupdate.h:843 [inline]
 ip_finish_output2+0xee8/0x1290 net/ipv4/ip_output.c:229
 dst_output include/net/dst.h:444 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 __ip_queue_xmit+0x12e3/0x1da0 net/ipv4/ip_output.c:532
 __tcp_transmit_skb+0x1e23/0x3340 net/ipv4/tcp_output.c:1399
 tcp_transmit_skb net/ipv4/tcp_output.c:1417 [inline]
 tcp_write_xmit+0x1a60/0x64c0 net/ipv4/tcp_output.c:2693
 __tcp_push_pending_frames+0x94/0x250 net/ipv4/tcp_output.c:2877
 tcp_sendmsg_locked+0x37af/0x4100 net/ipv4/tcp.c:1456
 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1484
 sock_sendmsg_nosec net/socket.c:724 [inline]
 sock_sendmsg net/socket.c:747 [inline]
 sock_write_iter+0x397/0x520 net/socket.c:1138
 call_write_iter include/linux/fs.h:1851 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x7b2/0xbb0 fs/read_write.c:584
 ksys_write+0x1a0/0x2c0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x403ace
RSP: 002b:000000c0084a5100 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000403ace
RDX: 00000000000000f0 RSI: 000000c000228200 RDI: 0000000000000003
RBP: 000000c0084a5140 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000000c0084a5280
R13: 0000000000000000 R14: 000000c0004864e0 R15: 000000c0000ae900
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g27681 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=21157
rcu: rcu_preempt kthread starved for 10502 jiffies! g27681 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:I stack:26552 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5304 [inline]
 __schedule+0x173b/0x4630 kernel/sched/core.c:6622
 schedule+0xc3/0x180 kernel/sched/core.c:6698
 schedule_timeout+0x1bd/0x310 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x2c6/0x1010 kernel/rcu/tree.c:1608
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:1807
 kthread+0x270/0x300 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 8652 Comm: syz-executor.0 Not tainted 6.3.0-rc3-syzkaller-00016-g2faac9a98f01 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
RIP: 0010:__sanitizer_cov_trace_const_cmp2+0x80/0x90 kernel/kcov.c:299
Code: 8d 42 28 4c 39 c8 77 22 89 f8 89 f6 49 ff c2 4c 89 11 48 c7 44 0a 08 03 00 00 00 48 89 44 0a 10 48 89 74 0a 18 4c 89 44 0a 20 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 4c 8b
RSP: 0018:ffffc90000007c88 EFLAGS: 00000046
RAX: 0000000080010002 RBX: ffff888044f71940 RCX: ffff888044f71940
RDX: ffff8880475a1d40 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 174e97c07ab70000 R08: ffffffff88c7d845 R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: 0000000000000000
R13: 174e97c07ab60000 R14: ffff888044f71800 R15: ffff8880454fb340
FS:  00007fb06c6cc700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb06b9ad988 CR3: 0000000026de3000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 advance_sched+0x4e5/0xc80 net/sched/sch_taprio.c:963
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x59f/0xd10 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x396/0x980 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1096 [inline]
 __sysvec_apic_timer_interrupt+0x13f/0x480 arch/x86/kernel/apic/apic.c:1113
 sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1107
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645
RIP: 0010:finish_lock_switch+0x95/0x110 kernel/sched/core.c:5063
Code: 45 31 c9 68 67 96 60 81 e8 d8 81 09 00 48 83 c4 08 4c 89 ff e8 bc c2 fe ff 66 90 4c 89 ff e8 a2 8b 49 09 e8 3d 71 30 00 fb 5b <41> 5c 41 5d 41 5e 41 5f c3 44 89 f1 80 e1 07 80 c1 03 38 c1 7c 83
RSP: 0018:ffffc9001599fea8 EFLAGS: 00000286
RAX: 11debd1e69c8e600 RBX: ffff88801b820034 RCX: ffffffff91ad7003
RDX: dffffc0000000000 RSI: ffffffff8aea7d60 RDI: ffffffff8b37fdc0
RBP: ffffc9001599ff20 R08: dffffc0000000000 R09: fffffbfff1ca6eae
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: 1ffff1101730797b R14: ffff8880b983cbd8 R15: ffff8880b983be80
 finish_task_switch+0x134/0x650 kernel/sched/core.c:5181
 schedule_tail+0xf/0xb0 kernel/sched/core.c:5239
 ret_from_fork+0x8/0x30 arch/x86/entry/entry_64.S:293
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/03/22 00:22 upstream 2faac9a98f01 8b4eb097 .config console log report info ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in schedule_tail
2023/06/07 02:06 upstream a4d7d7011219 a4ae4f42 .config console log report info ci-qemu2-arm64-compat BUG: soft lockup in schedule_tail
* Struck through repros no longer work on HEAD.