INFO: rcu detected stall in rtnl_dellink (3)

Status: upstream: reported on 2026/10/12 00:39
Reported-by: syzbot+0815ef6f1faf4a43d915@syzkaller.appspotmail.com
First crash: 8d19h, last: 8d19h
▶ ▼ Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in rtnl_dellink 1 1 604d 604d 0/3 auto-obsoleted due to no activity on 2025/06/03 01:04
linux-6.6 INFO: rcu detected stall in rtnl_dellink 1 1 268d 268d 0/2 auto-obsoleted due to no activity on 2026/05/05 01:43
linux-5.15 INFO: rcu detected stall in rtnl_dellink (3) 1 4 7d01h 36d 0/3 upstream: reported on 2026/09/14 01:32
linux-6.1 INFO: rcu detected stall in rtnl_dellink (2) 1 3 184d 257d 0/3 auto-obsoleted due to no activity on 2026/07/28 06:17
linux-5.15 INFO: rcu detected stall in rtnl_dellink (2) 1 3 148d 253d 0/3 auto-obsoleted due to no activity on 2026/09/02 10:41
upstream INFO: rcu detected stall in rtnl_dellink net 1 2 604d 672d 0/29 auto-obsoleted due to no activity on 2025/05/23 22:00
linux-5.15 INFO: rcu detected stall in rtnl_dellink 1 3 392d 472d 0/3 auto-obsoleted due to no activity on 2026/01/01 07:23

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-.... } 2669 jiffies s: 266773 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: 14762 Comm: syz.4.9731 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:22 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:130 [inline]
RIP: 0010:rcu_read_unlock_special+0x3e8/0x510 kernel/rcu/tree_plugin.h:681
Code: 30 48 8b 7c 24 28 e8 97 99 21 00 eb 1d bf 09 00 00 00 e8 eb 41 e2 ff 4c 8b 64 24 18 41 f7 c4 00 02 00 00 74 05 e8 88 a5 1b 00 <42> c6 44 2b 04 00 48 c7 44 24 60 00 00 00 00 9c 8f 44 24 60 f7 44
RSP: 0018:ffffc90000007240 EFLAGS: 00000046
RAX: ffffffff818ea401 RBX: 1ffff92000000e50 RCX: ffff88805c211e00
RDX: 0000000000000100 RSI: 0000000000000101 RDI: 0000000000000000
RBP: ffffc90000007340 R08: ffffc90000007167 R09: 1ffff92000000e2c
R10: dffffc0000000000 R11: fffff52000000e2d R12: 0000000000000046
R13: dffffc0000000000 R14: ffff8880b8c3bbc8 R15: 1ffff1101718777a
FS:  00007fe249bf66c0(0000) GS:ffff8880b8c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff27f634ff8 CR3: 0000000064237000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000200000000340 DR2: 0000200000000340
DR3: 0000200000000340 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 __perf_event_output kernel/events/core.c:7751 [inline]
 perf_event_output_forward+0x271/0x2f0 kernel/events/core.c:7760
 __perf_event_overflow+0x457/0x630 kernel/events/core.c:9506
 perf_swevent_overflow+0x19b/0x230 kernel/events/core.c:9589
 perf_swevent_event+0x458/0x570 kernel/events/core.c:-1
 perf_tp_event+0x36b/0xc10 kernel/events/core.c:10074
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10042
 perf_trace_preemptirq_template+0x268/0x320 include/trace/events/preemptirq.h:14
 trace_irq_enable_rcuidle+0xd3/0x140 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x24/0x40 kernel/trace/trace_preemptirq.c:44
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728
RIP: 0010:rcu_read_unlock_special+0x7f/0x510 kernel/rcu/tree_plugin.h:685
Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 d2 68 95 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc90000007ae0 EFLAGS: 00000206
RAX: 51b1ea119aecc500 RBX: 1ffff92000000f64 RCX: 51b1ea119aecc500
RDX: dffffc0000000000 RSI: ffffffff8a8c19a0 RDI: ffffffff8adf71a0
RBP: ffffc90000007bd0 R08: ffffffff9193424f R09: 1ffffffff2326849
R10: dffffc0000000000 R11: fffffbfff232684a R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8c3bb00 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 ieee80211_iterate_active_interfaces_atomic+0x156/0x170 net/mac80211/util.c:826
 mac80211_hwsim_beacon+0xb7/0x1b0 drivers/net/wireless/mac80211_hwsim.c:2153
 __run_hrtimer kernel/time/hrtimer.c:1751 [inline]
 __hrtimer_run_queues+0x522/0xc90 kernel/time/hrtimer.c:1815
 hrtimer_run_softirq+0x173/0x290 kernel/time/hrtimer.c:1832
 handle_softirqs+0x291/0x910 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:should_resched arch/x86/include/asm/preempt.h:103 [inline]
RIP: 0010:__local_bh_enable_ip+0x13e/0x1c0 kernel/softirq.c:428
Code: 8a e8 e6 b2 e4 08 65 66 8b 05 9e 65 b4 7e 66 85 c0 75 54 bf 01 00 00 00 e8 cf 82 09 00 e8 ba 72 39 00 fb 65 8b 05 8a 32 b3 7e <85> c0 75 05 e8 99 46 b1 ff 48 c7 04 24 0e 36 e0 45 4b c7 04 37 00
RSP: 0018:ffffc90004ed68a0 EFLAGS: 00000286
RAX: 0000000080000000 RBX: 0000000000000201 RCX: 51b1ea119aecc500
RDX: dffffc0000000000 RSI: ffffffff8a8c19a0 RDI: ffffffff8adf71a0
RBP: ffffc90004ed6930 R08: ffffffff9193424f R09: 1ffffffff2326849
R10: dffffc0000000000 R11: fffffbfff232684a R12: ffffffff88f4ac67
R13: ffff88806146b1b8 R14: dffffc0000000000 R15: 1ffff920009dad14
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 addrconf_ifdown+0x697/0x1a30 net/ipv6/addrconf.c:3867
 addrconf_notify+0x405/0xf60 net/ipv6/addrconf.c:-1
 notifier_call_chain kernel/notifier.c:87 [inline]
 raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:455
 call_netdevice_notifiers_extack net/core/dev.c:2052 [inline]
 call_netdevice_notifiers net/core/dev.c:2066 [inline]
 dev_close_many+0x2a2/0x400 net/core/dev.c:1614
 unregister_netdevice_many_notify+0x497/0x1990 net/core/dev.c:10997
 macsec_notify+0x43d/0x680 drivers/net/macsec.c:4389
 notifier_call_chain kernel/notifier.c:87 [inline]
 raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:455
 call_netdevice_notifiers_extack net/core/dev.c:2052 [inline]
 call_netdevice_notifiers net/core/dev.c:2066 [inline]
 unregister_netdevice_many_notify+0x10b1/0x1990 net/core/dev.c:11023
 rtnl_delete_link net/core/rtnetlink.c:3187 [inline]
 rtnl_dellink+0x55d/0x830 net/core/rtnetlink.c:3239
 rtnetlink_rcv_msg+0x863/0xfb0 net/core/rtnetlink.c:6166
 netlink_rcv_skb+0x1ef/0x440 net/netlink/af_netlink.c:2516
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x7ad/0x920 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8ad/0xbd0 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5ed/0x9a0 net/socket.c:2519
 ___sys_sendmsg+0x2a2/0x360 net/socket.c:2573
 __sys_sendmsg net/socket.c:2602 [inline]
 __do_sys_sendmsg net/socket.c:2611 [inline]
 __se_sys_sendmsg+0x1c3/0x2b0 net/socket.c:2609
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fe24b99e1d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe249bf6028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fe24bc25fa0 RCX: 00007fe24b99e1d9
RDX: 0000000000000000 RSI: 00002000000000c0 RDI: 0000000000000009
RBP: 00007fe24ba35888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe24bc26038 R14: 00007fe24bc25fa0 R15: 00007ffe2a0d9758
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/12 00:38 linux-6.1.y a500ba24937a 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in rtnl_dellink
* Struck through repros no longer work on HEAD.