INFO: rcu detected stall in netlink_deliver_tap

Status: auto-obsoleted due to no activity on 2026/10/03 14:40
Subsystems: net
Labels: prio:normal
[Documentation on labels]
First crash: 101d, last: 101d
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ID Workflow Result Correct Bug Created Started Finished Revision
a20444d8 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ INFO: rcu detected stall in netlink_deliver_tap 2026/07/07 00:01 2026/07/07 00:01 2026/07/07 00:46 93f57954
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in netlink_deliver_tap 1 1 242d 242d 0/3 auto-obsoleted due to no activity on 2026/05/25 10:08

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P29/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=29829, q=693 ncpus=2)
task:kworker/1:1     state:R  running task     stack:22984 pid:29    tgid:29    ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x125c/0x6730 kernel/sched/core.c:7234
 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7556
 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline]
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
 irqentry_exit+0x205/0xa00 kernel/entry/common.c:167
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:679
RIP: 0010:orc_ip arch/x86/kernel/unwind_orc.c:81 [inline]
RIP: 0010:__orc_find+0x70/0xf0 arch/x86/kernel/unwind_orc.c:103
Code: ec 72 4e 4c 89 e2 48 29 ea 48 89 d6 48 c1 ea 3f 48 c1 fe 02 48 01 f2 48 d1 fa 48 8d 5c 95 00 48 89 da 48 c1 ea 03 0f b6 34 0a <48> 89 da 83 e2 07 83 c2 03 40 38 f2 7c 05 40 84 f6 75 4b 48 63 13
RSP: 0018:ffffc90000a46770 EFLAGS: 00000a03
RAX: ffffffff91bc9d54 RBX: ffffffff9136192c RCX: dffffc0000000000
RDX: 1ffffffff226c325 RSI: 0000000000000000 RDI: ffffffff9136192c
RBP: ffffffff9136192c R08: ffffffff91bc9d60 R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000004e06 R12: ffffffff91361930
R13: ffffffff814e0622 R14: ffffffff9136192c R15: ffffffff9136192c
 orc_find arch/x86/kernel/unwind_orc.c:238 [inline]
 unwind_next_frame+0x2ec/0x2090 arch/x86/kernel/unwind_orc.c:510
 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5362 [inline]
 __kmalloc_node_track_caller_noprof+0x331/0x830 mm/slub.c:5497
 kvasprintf+0xbc/0x150 lib/kasprintf.c:25
 kvasprintf_const+0x66/0x1a0 lib/kasprintf.c:49
 kobject_set_name_vargs+0x5a/0x140 lib/kobject.c:274
 dev_set_name+0xc7/0x100 drivers/base/core.c:3560
 i2c_register_adapter+0x337/0x1390 drivers/i2c/i2c-core-base.c:1588
 dvb_usb_i2c_init+0x24e/0x330 drivers/media/usb/dvb-usb/dvb-usb-i2c.c:31
 dvb_usb_init drivers/media/usb/dvb-usb/dvb-usb-init.c:183 [inline]
 dvb_usb_device_init.cold+0x37a/0x14bb drivers/media/usb/dvb-usb/dvb-usb-init.c:310
 digitv_probe+0x8d/0x150 drivers/media/usb/dvb-usb/digitv.c:282
 usb_probe_interface+0x303/0x8f0 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:628 [inline]
 really_probe+0x241/0xa60 drivers/base/dd.c:706
 __driver_probe_device+0x20e/0x450 drivers/base/dd.c:868
 driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
 __device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098
 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153
 bus_probe_device+0x64/0x160 drivers/base/bus.c:620
 device_add+0x121d/0x1970 drivers/base/core.c:3772
 usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2268
 usb_generic_driver_probe+0xa1/0xe0 drivers/usb/core/generic.c:250
 usb_probe_device+0xef/0x400 drivers/usb/core/driver.c:291
 call_driver_probe drivers/base/dd.c:628 [inline]
 really_probe+0x241/0xa60 drivers/base/dd.c:706
 __driver_probe_device+0x20e/0x450 drivers/base/dd.c:868
 driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
 __device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098
 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153
 bus_probe_device+0x64/0x160 drivers/base/bus.c:620
 device_add+0x121d/0x1970 drivers/base/core.c:3772
 usb_new_device.cold+0x685/0x115c drivers/usb/core/hub.c:2695
 hub_port_connect drivers/usb/core/hub.c:5567 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
 port_event drivers/usb/core/hub.c:5871 [inline]
 hub_event+0x314d/0x4af0 drivers/usb/core/hub.c:5953
 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
 process_scheduled_works kernel/workqueue.c:3405 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10493 jiffies! g29829 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=11241
rcu: rcu_preempt kthread starved for 10494 jiffies! g29829 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:27432 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x125c/0x6730 kernel/sched/core.c:7234
 __schedule_loop kernel/sched/core.c:7311 [inline]
 schedule+0xdd/0x2c0 kernel/sched/core.c:7326
 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123
 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </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 UID: 0 PID: 7168 Comm: syz.2.248 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:mark_usage kernel/locking/lockdep.c:4652 [inline]
RIP: 0010:__lock_acquire+0x458/0x1a40 kernel/locking/lockdep.c:5191
Code: 8b 05 84 37 7e 12 f6 43 22 03 0f 84 4c 02 00 00 85 c0 0f 85 38 0c 00 00 8b 85 84 0b 00 00 85 c0 0f 85 8f 0b 00 00 0f b6 43 22 <a8> 18 75 33 a8 03 0f 84 70 03 00 00 ba 03 00 00 00 48 89 de 48 89
RSP: 0018:ffffc90000007c18 EFLAGS: 00000046
RAX: 000000000000000c RBX: ffff88802f5fd738 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffff88802f5fd738 RDI: ffff88802f5fca80
RBP: ffff88802f5fca80 R08: 0000000000000001 R09: 0000000000000002
R10: 0000000000000006 R11: 0000000000000007 R12: 0000000000000000
R13: 0000000000000007 R14: 0000000000000000 R15: 0000000000000007
FS:  00007ff4acdf76c0(0000) GS:ffff888123dec000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f03d8000020 CR3: 00000000734f5000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 lock_acquire kernel/locking/lockdep.c:5868 [inline]
 lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
 _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:166
 debug_object_activate+0x144/0x4b0 lib/debugobjects.c:873
 debug_hrtimer_activate kernel/time/hrtimer.c:485 [inline]
 debug_activate kernel/time/hrtimer.c:528 [inline]
 enqueue_hrtimer+0x75/0x2f0 kernel/time/hrtimer.c:1109
 __run_hrtimer kernel/time/hrtimer.c:2048 [inline]
 __hrtimer_run_queues+0x6ed/0x9c0 kernel/time/hrtimer.c:2096
 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2215
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
 __sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:check_preemption_disabled+0x26/0xe0 lib/smp_processor_id.c:54
Code: 90 90 90 90 41 54 55 53 48 83 ec 08 65 8b 1d d5 75 aa 08 65 f7 05 c6 75 aa 08 ff ff ff 7f 74 0f 48 83 c4 08 89 d8 5b 5d 41 5c <c3> cc cc cc cc 9c 58 f6 c4 02 74 ea 65 4c 8b 25 8e 75 aa 08 48 89
RSP: 0018:ffffc900035a6b08 EFLAGS: 00000296
RAX: 0000000000000000 RBX: ffffc900035a7380 RCX: ffffffff925d1601
RDX: ffffc900035a7388 RSI: ffffffff8c400c00 RDI: ffffffff8c400c40
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000007
R10: 0000000000000200 R11: 000000000008cd9a R12: ffffc900035a6be8
R13: ffffc900035a6b98 R14: ffffc900035a7380 R15: ffffc900035a6bcc
 rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
 rcu_is_watching+0x12/0xc0 kernel/rcu/tree.c:752
 rcu_read_unlock include/linux/rcupdate.h:869 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1183 [inline]
 unwind_next_frame+0x745/0x2090 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4612 [inline]
 slab_alloc_node mm/slub.c:4945 [inline]
 kmem_cache_alloc_noprof+0x26b/0x6a0 mm/slub.c:4959
 skb_clone+0x190/0x400 net/core/skbuff.c:2110
 dev_queue_xmit_nit+0x255/0xa60 net/core/dev.c:2575
 xmit_one net/core/dev.c:3885 [inline]
 dev_hard_start_xmit+0x2f5/0x760 net/core/dev.c:3905
 __dev_queue_xmit+0x1b9d/0x4940 net/core/dev.c:4872
 dev_queue_xmit include/linux/netdevice.h:3446 [inline]
 __netlink_deliver_tap_skb net/netlink/af_netlink.c:308 [inline]
 __netlink_deliver_tap net/netlink/af_netlink.c:326 [inline]
 netlink_deliver_tap+0xa4d/0xcc0 net/netlink/af_netlink.c:339
 __netlink_sendskb net/netlink/af_netlink.c:1261 [inline]
 netlink_dump+0x909/0xd00 net/netlink/af_netlink.c:2373
 __netlink_dump_start+0x6d6/0x990 net/netlink/af_netlink.c:2446
 netlink_dump_start include/linux/netlink.h:341 [inline]
 xfrm_user_rcv_msg+0x879/0xd80 net/xfrm/xfrm_user.c:3867
 netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2556
 xfrm_netlink_rcv+0x71/0x90 net/xfrm/xfrm_user.c:3910
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec net/socket.c:775 [inline]
 __sock_sendmsg net/socket.c:790 [inline]
 ____sys_sendmsg+0xa4d/0xbe0 net/socket.c:2684
 ___sys_sendmsg+0x190/0x1e0 net/socket.c:2738
 __sys_sendmsg+0x160/0x210 net/socket.c:2770
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff4abf9de59
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:00007ff4acdf7028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ff4ac226090 RCX: 00007ff4abf9de59
RDX: 0000000000000000 RSI: 0000200000000040 RDI: 000000000000000c
RBP: 00007ff4ac033e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff4ac226128 R14: 00007ff4ac226090 R15: 00007ffdd5e556d8
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/05 14:29 upstream 7404ce516372 fcece630 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in netlink_deliver_tap
* Struck through repros no longer work on HEAD.