INFO: rcu detected stall in rtnl_dellink (2)

Status: upstream: reported on 2026/02/09 08:45
Reported-by: syzbot+5ba61b2fe62d7a25a361@syzkaller.appspotmail.com
First crash: 166d, last: 60d
▶ ▼ 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 517d 517d 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 181d 181d 0/2 auto-obsoleted due to no activity on 2026/05/05 01:43
linux-6.1 INFO: rcu detected stall in rtnl_dellink (2) 1 3 97d 170d 0/3 upstream: reported on 2026/02/05 02:24
upstream INFO: rcu detected stall in rtnl_dellink net 1 2 517d 585d 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 305d 384d 0/3 auto-obsoleted due to no activity on 2026/01/01 07:23

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-....: (1 GPs behind) idle=4f1/1/0x4000000000000002 softirq=41240/41241 fqs=5250 
	(detected by 1, t=10502 jiffies, g=53397, q=321)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 15700 Comm: syz.5.3018 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:__srcu_read_lock+0x25/0x80 kernel/rcu/srcutree.c:404
Code: 00 00 0f 1f 00 41 57 41 56 53 48 89 fb 49 bf 00 00 00 00 00 fc ff df 48 81 c7 08 02 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 38 <84> c0 75 3f 44 8b b3 08 02 00 00 41 83 e6 01 48 81 c3 30 02 00 00
RSP: 0018:ffffc90000007858 EFLAGS: 00000806
RAX: 0000000000000000 RBX: ffffffff8c35eb40 RCX: ffff888029899dc0
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffffffff8c35ed48
RBP: 0000000000000000 R08: ffffffff8d89f82f R09: 1ffffffff1b13f05
R10: dffffc0000000000 R11: fffffbfff1b13f06 R12: 0000000000000000
R13: 0000000000000000 R14: ffffffff89e00e46 R15: dffffc0000000000
FS:  00007f1b664b96c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c34b855 CR3: 000000001f392000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff1 DR7: 0000000000000600
Call Trace:
 <IRQ>
 srcu_read_lock_notrace include/linux/srcu.h:174 [inline]
 trace_irq_enable_rcuidle+0xbf/0x180 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674
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 df 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc90000007960 EFLAGS: 00000206
RAX: 5375d2b065803100 RBX: 1ffff92000000f30 RCX: 5375d2b065803100
RDX: dffffc0000000000 RSI: ffffffff8a2b3100 RDI: ffffffff8a7a0700
RBP: ffffc90000007a40 R08: ffffffff901d61c7 R09: 1ffffffff203ac38
R10: dffffc0000000000 R11: fffffbfff203ac39 R12: ffffffff8c323800
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
 rcu_read_unlock include/linux/rcupdate.h:772 [inline]
 ipv6_get_lladdr+0x333/0x3b0 net/ipv6/addrconf.c:1896
 addrconf_rs_timer+0x273/0x630 net/ipv6/addrconf.c:3955
 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
 expire_timers kernel/time/timer.c:1699 [inline]
 __run_timers+0x53e/0x800 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x339/0x830 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xbc/0x120 kernel/locking/spinlock.c:194
Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> bf 2a 8c f7 65 8b 05 f0 26 3c 76 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc90002d9e460 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a02 RCX: 5375d2b065803100
RDX: dffffc0000000000 RSI: ffffffff8a2b3100 RDI: 0000000000000001
RBP: ffffc90002d9e4f8 R08: ffffffff901d60cf R09: 1ffffffff203ac19
R10: dffffc0000000000 R11: fffffbfff203ac1a R12: dffffc0000000000
R13: ffff888055660000 R14: ffffffff964a22a8 R15: 1ffff920005b3c8c
 __debug_check_no_obj_freed lib/debugobjects.c:982 [inline]
 debug_check_no_obj_freed+0x515/0x530 lib/debugobjects.c:1003
 free_pages_prepare mm/page_alloc.c:1345 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x237/0x6c0 mm/page_alloc.c:3317
 free_unref_page+0x8f/0x2a0 mm/page_alloc.c:3396
 free_slab mm/slub.c:2020 [inline]
 discard_slab mm/slub.c:2026 [inline]
 __unfreeze_partials+0x1a5/0x200 mm/slub.c:2512
 put_cpu_partial+0x12d/0x190 mm/slub.c:2592
 qlist_free_all+0x35/0x90 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x150/0x160 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x2f/0xd0 mm/kasan/common.c:444
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519
 slab_alloc_node mm/slub.c:3225 [inline]
 slab_alloc mm/slub.c:3233 [inline]
 kmem_cache_alloc_trace+0x103/0x2a0 mm/slub.c:3250
 kmalloc include/linux/slab.h:607 [inline]
 kzalloc include/linux/slab.h:738 [inline]
 kobject_uevent_env+0x27a/0x890 lib/kobject_uevent.c:539
 __kobject_del+0xd2/0x2f0 lib/kobject.c:625
 kobject_cleanup lib/kobject.c:704 [inline]
 kobject_release lib/kobject.c:744 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x235/0x460 lib/kobject.c:761
 net_rx_queue_update_kobjects+0x420/0x490 net/core/net-sysfs.c:1124
 remove_queue_kobjects net/core/net-sysfs.c:1822 [inline]
 netdev_unregister_kobject+0x111/0x250 net/core/net-sysfs.c:1976
 unregister_netdevice_many+0x1518/0x19f0 net/core/dev.c:11187
 ipvlan_device_event+0x971/0x9f0 drivers/net/ipvlan/ipvlan_main.c:764
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391
 call_netdevice_notifiers_extack net/core/dev.c:2074 [inline]
 call_netdevice_notifiers net/core/dev.c:2088 [inline]
 unregister_netdevice_many+0x1049/0x19f0 net/core/dev.c:11160
 rtnl_delete_link net/core/rtnetlink.c:3117 [inline]
 rtnl_dellink+0x52b/0x7b0 net/core/rtnetlink.c:3168
 rtnetlink_rcv_msg+0x844/0xf30 net/core/rtnetlink.c:5687
 netlink_rcv_skb+0x1f5/0x440 net/netlink/af_netlink.c:2507
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x774/0x920 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:706 [inline]
 __sock_sendmsg net/socket.c:718 [inline]
 ____sys_sendmsg+0x5b7/0x8f0 net/socket.c:2445
 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2499
 __sys_sendmsg net/socket.c:2528 [inline]
 __do_sys_sendmsg net/socket.c:2537 [inline]
 __se_sys_sendmsg+0x1af/0x290 net/socket.c:2535
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f1b6825fe59
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:00007f1b664b9028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f1b684d8fa0 RCX: 00007f1b6825fe59
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000005
RBP: 00007f1b682f5d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1b684d9038 R14: 00007f1b684d8fa0 R15: 00007ffdb1a03418
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/25 10:41 linux-5.15.y 241d66fa280c c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in rtnl_dellink
2026/02/16 01:31 linux-5.15.y e45d5d41c134 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in rtnl_dellink
2026/02/09 08:44 linux-5.15.y 7b232985052f 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in rtnl_dellink
* Struck through repros no longer work on HEAD.