INFO: rcu detected stall in rtnl_dellink (2)

Status: upstream: reported on 2026/02/05 02:24
Reported-by: syzbot+8f938bb07bba5be3eaeb@syzkaller.appspotmail.com
First crash: 172d, last: 99d
▶ ▼ Similar bugs (5)
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 519d 519d 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 183d 183d 0/2 auto-obsoleted due to no activity on 2026/05/05 01:43
linux-5.15 INFO: rcu detected stall in rtnl_dellink (2) 1 3 62d 168d 0/3 upstream: reported on 2026/02/09 08:45
upstream INFO: rcu detected stall in rtnl_dellink net 1 2 519d 587d 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 307d 386d 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: { 1-.... } 2681 jiffies s: 177737 root: 0x2/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 21811 Comm: syz.4.5391 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:101 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0x65/0x290 mm/kasan/generic.c:189
Code: ff df 49 89 fe 49 c1 ee 03 49 ba 00 00 00 00 00 fc ff df 4f 8d 1c 16 4c 8d 44 3e ff 4d 89 c1 49 c1 e9 03 4b 8d 1c 21 49 89 df <4d> 29 df 49 83 ff 10 7f 29 4d 85 ff 0f 84 38 01 00 00 4c 89 cb 48
RSP: 0018:ffffc900001e0350 EFLAGS: 00000807
RAX: ffffffff81a51c01 RBX: fffff5200003c083 RCX: ffffffff81a51d44
RDX: 0000000000000001 RSI: 0000000000000038 RDI: ffffc900001e03e0
RBP: 0000000000000000 R08: ffffc900001e0417 R09: 1ffff9200003c082
R10: dffffc0000000000 R11: fffff5200003c07c R12: dffffc0000000001
R13: ffffc900001e0440 R14: 1ffff9200003c07c R15: fffff5200003c083
FS:  00007ff8685a66c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000029c0 CR3: 0000000029675000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 memset+0x1e/0x40 mm/kasan/shadow.c:44
 __perf_event_output kernel/events/core.c:7723 [inline]
 perf_event_output_forward+0x184/0x2f0 kernel/events/core.c:7750
 __perf_event_overflow+0x448/0x610 kernel/events/core.c:9496
 perf_swevent_overflow kernel/events/core.c:9579 [inline]
 perf_swevent_event+0x315/0x570 kernel/events/core.c:9630
 perf_tp_event+0x3e7/0xc30 kernel/events/core.c:10064
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10032
 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 33 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:ffffc900001e0ac0 EFLAGS: 00000206
RAX: 14f34eb8b9925000 RBX: 1ffff9200003c160 RCX: 14f34eb8b9925000
RDX: dffffc0000000000 RSI: ffffffff8a8c1120 RDI: ffffffff8adf13a0
RBP: ffffc900001e0bb0 R08: ffffffff90af924f R09: 1ffffffff215f249
R10: dffffc0000000000 R11: fffffbfff215f24a R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8f3b900 R15: 0000000000000002
 __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:2147
 __run_hrtimer kernel/time/hrtimer.c:1747 [inline]
 __hrtimer_run_queues+0x54a/0xd50 kernel/time/hrtimer.c:1811
 hrtimer_run_softirq+0x183/0x2a0 kernel/time/hrtimer.c:1828
 handle_softirqs+0x2a1/0x930 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:orc_find arch/x86/kernel/unwind_orc.c:169 [inline]
RIP: 0010:unwind_next_frame+0x1d3/0x20b0 arch/x86/kernel/unwind_orc.c:448
Code: f4 17 00 00 44 89 f0 4c 8d 24 85 dc 7c 3e 8f 4c 89 e0 48 c1 e8 03 42 0f b6 04 28 84 c0 4d 89 ef 0f 85 57 19 00 00 45 8b 24 24 <44> 89 f0 ff c0 4c 8d 2c 85 dc 7c 3e 8f 4c 89 e8 48 c1 e8 03 42 0f
RSP: 0018:ffffc90005cd62b0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffc90005cd6388 RCX: ffffffff96c00100
RDX: dffffc0000000000 RSI: 0000000000096079 RDI: ffffffff81391adf
RBP: ffffffff8a0bfe5e R08: ffffc90005cd6450 R09: 000000000000000c
R10: dffffc0000000000 R11: fffff52000b9ac7d R12: 000000000019edc2
R13: dffffc0000000000 R14: 0000000000090bfe R15: dffffc0000000000
 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 ____kasan_kmalloc mm/kasan/common.c:375 [inline]
 __kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:384
 kmalloc include/linux/slab.h:563 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 ipv6_add_addr+0x42d/0xfc0 net/ipv6/addrconf.c:1115
 addrconf_add_linklocal+0x26f/0x6d0 net/ipv6/addrconf.c:3257
 addrconf_addr_gen+0x55e/0x6a0 net/ipv6/addrconf.c:3388
 addrconf_init_auto_addrs+0x752/0xaf0 net/ipv6/addrconf.c:-1
 addrconf_notify+0xaca/0xf40 net/ipv6/addrconf.c:3685
 notifier_call_chain kernel/notifier.c:87 [inline]
 raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:455
 call_netdevice_notifiers_mtu net/core/dev.c:2089 [inline]
 dev_set_mtu_ext+0x45f/0x680 net/core/dev.c:8819
 dev_set_mtu+0x41/0xc0 net/core/dev.c:8840
 hsr_del_port+0x183/0x2b0 net/hsr/hsr_slave.c:227
 hsr_del_ports+0x2d/0x90 net/hsr/hsr_device.c:416
 hsr_dellink+0x3f/0x70 net/hsr/hsr_netlink.c:113
 rtnl_delete_link net/core/rtnetlink.c:3177 [inline]
 rtnl_dellink+0x54c/0x830 net/core/rtnetlink.c:3230
 rtnetlink_rcv_msg+0x87c/0xfc0 net/core/rtnetlink.c:6157
 netlink_rcv_skb+0x1fb/0x450 net/netlink/af_netlink.c:2511
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x74d/0x8d0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8ad/0xbd0 net/netlink/af_netlink.c:1872
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5be/0x970 net/socket.c:2518
 ___sys_sendmsg+0x2a2/0x360 net/socket.c:2572
 __sys_sendmsg net/socket.c:2601 [inline]
 __do_sys_sendmsg net/socket.c:2610 [inline]
 __se_sys_sendmsg+0x1bb/0x2a0 net/socket.c:2608
 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: 0033:0x7ff86779c819
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:00007ff8685a6028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ff867a15fa0 RCX: 00007ff86779c819
RDX: 0000000000044004 RSI: 0000200000000600 RDI: 0000000000000009
RBP: 00007ff867832c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff867a16038 R14: 00007ff867a15fa0 R15: 00007ffc5e201438
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/19 06:17 linux-6.1.y 7c87defbd336 303e2802 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in rtnl_dellink
2026/04/03 07:55 linux-6.1.y 1989cd3d56e2 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in rtnl_dellink
2026/02/05 02:23 linux-6.1.y cd9b81672742 ea10c935 .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.