syzbot

 sign-in | mailing list | source | docs | 🏰
🐞 Open [1340]
≡ Subsystems
🐞 Fixed [7129]
🐞 Invalid [18870]
⬇ Missing Backports [220]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
Total Repo Heatmap Subsystems Heatmap
✨ AI
💬 Send us feedback

INFO: rcu detected stall in clone3 (4)

Status: auto-obsoleted due to no activity on 2023/11/22 09:08
Subsystems: mm net
[Documentation on labels]
First crash: 1093d, last: 1013d
▶ ▼ Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 INFO: rcu detected stall in clone3 origin:lts-only 1 C inconclusive 2 179d 243d 0/2 upstream: reported C repro on 2025/10/02 07:48
upstream INFO: rcu detected stall in clone3 (5) mm 1 7 519d 729d 0/29 auto-obsoleted due to no activity on 2025/03/30 08:38
upstream INFO: rcu detected stall in clone3 mm 1 2 1603d 1629d 0/29 closed as invalid on 2022/02/08 10:10
linux-5.15 INFO: rcu detected stall in clone3 (2) 1 1 94d 94d 0/3 upstream: reported on 2026/03/01 00:21
linux-5.15 INFO: rcu detected stall in clone3 1 2 301d 335d 0/3 auto-obsoleted due to no activity on 2025/11/14 02:35
upstream INFO: rcu detected stall in clone3 (2) kernfs 1 1 1451d 1451d 0/29 auto-closed as invalid on 2022/09/10 23:49
upstream INFO: rcu detected stall in clone3 (3) kernel 1 1 1200d 1200d 0/29 auto-obsoleted due to no activity on 2023/05/19 23:49
upstream INFO: rcu detected stall in clone3 (6) cgroups mm prio:high 1 31 8d05h 6d05h 0/29 upstream: reported on 2026/05/28 01:12

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-.... } 2635 jiffies s: 53969 root: 0x1/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 24453 Comm: syz-executor.1 Not tainted 6.4.0-rc5-syzkaller-00002-gf8dba31b0a82 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:200
Code: 06 ef 8e 02 66 0f 1f 44 00 00 f3 0f 1e fa 48 8b be a8 01 00 00 e8 b0 ff ff ff 31 c0 c3 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 <f3> 0f 1e fa 65 8b 05 7d 75 7f 7e 89 c1 48 8b 34 24 81 e1 00 01 00
RSP: 0018:ffffc90000007618 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffff8880489afbe0 RCX: ffffffff883f1caa
RDX: ffff888021f73b80 RSI: 0000000000000100 RDI: 0000000000000001
RBP: ffff888028001800 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0200000000000000 R12: dffffc0000000000
R13: ffff888028001ae0 R14: ffff888028001af0 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b9800000(0063) knlGS:00000000f7ef9b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000002d945000 CR3: 000000001e689000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 __list_add include/linux/list.h:72 [inline]
 list_add_tail include/linux/list.h:102 [inline]
 list_move_tail include/linux/list.h:230 [inline]
 fq_pie_qdisc_dequeue+0x728/0x9c0 net/sched/sch_fq_pie.c:248
 dequeue_skb net/sched/sch_generic.c:292 [inline]
 qdisc_restart net/sched/sch_generic.c:397 [inline]
 __qdisc_run+0x1b2/0x1780 net/sched/sch_generic.c:415
 __dev_xmit_skb net/core/dev.c:3868 [inline]
 __dev_queue_xmit+0x2215/0x3b10 net/core/dev.c:4210
 dev_queue_xmit include/linux/netdevice.h:3085 [inline]
 neigh_connected_output+0x3c2/0x550 net/core/neighbour.c:1581
 neigh_output include/net/neighbour.h:544 [inline]
 ip6_finish_output2+0x55a/0x1560 net/ipv6/ip6_output.c:134
 __ip6_finish_output net/ipv6/ip6_output.c:195 [inline]
 ip6_finish_output+0x69a/0x1170 net/ipv6/ip6_output.c:206
 NF_HOOK_COND include/linux/netfilter.h:292 [inline]
 ip6_output+0x1f1/0x540 net/ipv6/ip6_output.c:227
 dst_output include/net/dst.h:458 [inline]
 NF_HOOK include/linux/netfilter.h:303 [inline]
 ndisc_send_skb+0xa63/0x1850 net/ipv6/ndisc.c:508
 ndisc_send_rs+0x132/0x6f0 net/ipv6/ndisc.c:718
 addrconf_rs_timer+0x3f1/0x870 net/ipv6/addrconf.c:3936
 call_timer_fn+0x1a0/0x580 kernel/time/timer.c:1700
 expire_timers+0x29b/0x4b0 kernel/time/timer.c:1751
 __run_timers kernel/time/timer.c:2022 [inline]
 __run_timers kernel/time/timer.c:1995 [inline]
 run_timer_softirq+0x326/0x910 kernel/time/timer.c:2035
 __do_softirq+0x1d4/0x905 kernel/softirq.c:571
 invoke_softirq kernel/softirq.c:445 [inline]
 __irq_exit_rcu+0x114/0x190 kernel/softirq.c:650
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:662
 sysvec_apic_timer_interrupt+0x97/0xc0 arch/x86/kernel/apic/apic.c:1106
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645
RIP: 0010:lock_release+0x3f4/0x670 kernel/locking/lockdep.c:5713
Code: 7e 83 f8 01 0f 85 40 01 00 00 9c 58 f6 c4 02 0f 85 2b 01 00 00 48 f7 04 24 00 02 00 00 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c5 48 c7 45 00 00 00 00 00 c7 45 08 00 00 00 00 48 8b 84 24
RSP: 0018:ffffc90016d1f718 EFLAGS: 00000206
RAX: dffffc0000000000 RBX: ecb24668d20c01a3 RCX: ffffc90016d1f768
RDX: 1ffff110043ee8c7 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 1ffff92002da3ee5 R08: 0000000000000001 R09: ffffffff8e7a7f17
R10: fffffbfff1cf4fe2 R11: 1ffff110050bf442 R12: 0000000000000001
R13: ffff888021f74640 R14: 0000000000000002 R15: ffff888021f73b80
 rcu_lock_release include/linux/rcupdate.h:332 [inline]
 rcu_read_unlock include/linux/rcupdate.h:806 [inline]
 inet_twsk_purge+0x562/0x900 net/ipv4/inet_timewait_sock.c:336
 ops_exit_list+0x125/0x170 net/core/net_namespace.c:175
 setup_net+0x7fb/0xc50 net/core/net_namespace.c:362
 copy_net_ns+0x4ee/0x8e0 net/core/net_namespace.c:491
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 copy_namespaces+0x410/0x500 kernel/nsproxy.c:179
 copy_process+0x322c/0x75c0 kernel/fork.c:2510
 kernel_clone+0xeb/0x890 kernel/fork.c:2915
 __do_sys_clone3+0x1cd/0x240 kernel/fork.c:3216
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 entry_SYSENTER_compat_after_hwframe+0x70/0x82
RIP: 0023:0xf7efe579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f7ef949c EFLAGS: 00000286 ORIG_RAX: 00000000000001b3
RAX: ffffffffffffffda RBX: 00000000f7ef94d0 RCX: 0000000000000058
RDX: 0000000000000000 RSI: 0000000040000000 RDI: 0000000000000000
RBP: 0000000020000180 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/06/05 23:27 upstream f8dba31b0a82 a4ae4f42 .config console log report info ci-upstream-kasan-gce-386 INFO: rcu detected stall in clone3
2023/08/24 09:03 linux-next 2b3bd393093b 4d7ae7ab .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in clone3
* Struck through repros no longer work on HEAD.