BUG: soft lockup in __netif_receive_skb_core (2)

Status: premoderation: reported on 2026/07/02 06:56
Reported-by: syzbot+c89265198ffdc57415a6@syzkaller.appspotmail.com
First crash: 21d, last: 21d
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-10 BUG: soft lockup in __netif_receive_skb_core 1 1 706d 706d 0/2 auto-obsoleted due to no activity on 2024/11/14 15:12
upstream INFO: rcu detected stall in __netif_receive_skb_core (2) batman 1 1 909d 909d 0/29 auto-obsoleted due to no activity on 2024/04/24 15:36
upstream INFO: rcu detected stall in __netif_receive_skb_core mm 1 1 1782d 1782d 0/29 auto-closed as invalid on 2021/12/03 17:24
linux-6.1 INFO: rcu detected stall in __netif_receive_skb_core 1 2 672d 720d 0/3 auto-obsoleted due to no activity on 2024/12/28 03:14
linux-6.1 INFO: rcu detected stall in __netif_receive_skb_core (2) 1 1 29d 29d 0/3 upstream: reported on 2026/06/24 03:33
upstream INFO: rcu detected stall in __netif_receive_skb_core (3) net 1 3 765d 798d 0/29 auto-obsoleted due to no activity on 2024/09/16 00:52

Sample crash report:
watchdog: BUG: soft lockup - CPU#1 stuck for 123s! [syz.8.32193:18812]
Modules linked in:
CPU: 1 PID: 18812 Comm: syz.8.32193 Tainted: G        W         syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__netif_receive_skb_core+0x2bdf/0x30b0 net/core/dev.c:5403
Code: 48 8b 9c 24 30 01 00 00 48 8b 84 24 88 00 00 00 42 80 3c 28 00 4c 8b b4 24 90 00 00 00 74 08 4c 89 f7 e8 84 de fe fd 49 89 1e <48> 8b 44 24 48 42 c6 44 28 12 f8 48 c7 84 24 a0 00 00 00 0e 36 e0
RSP: 0018:ffffc90000170b40 EFLAGS: 00000246
RAX: 1ffff9200002e1a6 RBX: ffff888141bf3dc0 RCX: ffff888164983b40
RDX: 0000000000000102 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000170d00 R08: ffff888164983b40 R09: 0000000000000002
R10: 000000000000a888 R11: 0000000000000102 R12: 0000000000000001
R13: dffffc0000000000 R14: ffffc90000170d30 R15: ffff88813b094000
FS:  00007f2bf291a6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2bf3f0e540 CR3: 000000012f17c000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000200000000300
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 __netif_receive_skb_one_core net/core/dev.c:5413 [inline]
 __netif_receive_skb+0x72/0x280 net/core/dev.c:5529
 process_backlog+0x351/0x600 net/core/dev.c:6436
 napi_poll net/core/dev.c:6887 [inline]
 net_rx_action+0x48d/0xed0 net/core/dev.c:6957
 __do_softirq+0x255/0x563 kernel/softirq.c:309
 asm_call_irq_on_stack+0xf/0x20
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline]
 do_softirq_own_stack+0x60/0x80 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:405 [inline]
 __irq_exit_rcu+0x128/0x150 kernel/softirq.c:435
 irq_exit_rcu+0x9/0x10 kernel/softirq.c:447
 sysvec_apic_timer_interrupt+0xbf/0xe0 arch/x86/kernel/apic/apic.c:1106
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:635
RIP: 0010:preempt_count_sub+0x52/0x170 kernel/sched/core.c:4493
Code: 83 3d 31 39 a3 05 00 75 25 65 8b 05 f4 9d bd 7e 89 c1 81 e1 ff ff ff 7f 39 cf 7f 27 81 ff ff 00 00 00 0f 93 c1 84 c0 0f 95 c0 <08> c8 74 55 65 8b 05 cf 9d bd 7e f7 df 65 01 3d c6 9d bd 7e 5b 41
RSP: 0018:ffffc90001067c30 EFLAGS: 00000202
RAX: 0000000000000001 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000040000002 RSI: 0000000000000000 RDI: 0000000000000001
RBP: ffffc90001067c40 R08: ffffffff86c373d3 R09: 1ffffffff0d86e7a
R10: dffffc0000000000 R11: fffffbfff0d86e7b R12: ffff8881f7155fc0
R13: ffff8881649827ac R14: 0000000000000000 R15: ffff888164983b40
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
 _raw_spin_unlock_irq+0x4e/0x70 kernel/locking/spinlock.c:199
 finish_lock_switch kernel/sched/core.c:3786 [inline]
 finish_task_switch+0x12e/0x5a0 kernel/sched/core.c:3886
 context_switch kernel/sched/core.c:4051 [inline]
 __schedule+0xc0b/0x13e0 kernel/sched/core.c:4806
 preempt_schedule_irq+0xaa/0x120 kernel/sched/core.c:5067
 irqentry_exit_cond_resched kernel/entry/common.c:365 [inline]
 irqentry_exit+0x56/0x60 kernel/entry/common.c:395
 sysvec_irq_work+0xc8/0xd0 arch/x86/kernel/irq_work.c:17
 asm_sysvec_irq_work+0x12/0x20 arch/x86/include/asm/idtentry.h:661
RIP: 0010:__syscall_enter_from_user_work kernel/entry/common.c:79 [inline]
RIP: 0010:syscall_enter_from_user_mode+0xc/0x30 kernel/entry/common.c:99
Code: 5d dc fd eb ca 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 e8 a7 fe ff ff 5d c3 00 00 cc cc 00 48 89 f0 fb 65 48 8b 0d 04 10 86 7b <48> 8b 31 f7 c6 c1 01 00 10 74 0a 55 48 89 e5 e8 00 d4 d7 fc 5d c3
RSP: 0018:ffffc90001067f38 EFLAGS: 00000246
RAX: 000000000000000f RBX: ffffc90001067f58 RCX: ffff888164983b40
RDX: 0000000000000000 RSI: 000000000000000f RDI: ffffc90001067f58
RBP: ffffc90001067f48 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f2bf3e621d9
Code: 11 06 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 0c 25
RSP: 002b:00007f2bf2919b40 EFLAGS: 00000206 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 00007f2bf4148fa8 RCX: 00007f2bf3e621d9
RDX: 00007f2bf2919b40 RSI: 00007f2bf2919c70 RDI: 0000000000000021
RBP: 00007f2bf4148fa0 R08: 00376bfa570f66bc R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f2bf4149038 R14: 00007ffeb6ba0040 R15: 00007ffeb6ba0128
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 18677 Comm: syz.0.32172 Tainted: G        W         syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:asm_sysvec_apic_timer_interrupt+0x0/0x20 arch/x86/include/asm/idtentry.h:634
Code: 00 90 90 90 90 90 90 90 90 90 0f 01 ca 6a ff e8 b6 03 00 00 48 89 e7 e8 2e 47 dc ff e9 a9 04 00 00 90 90 90 90 90 90 90 90 90 <0f> 01 ca 6a ff e8 96 03 00 00 48 89 e7 e8 5e 45 dc ff e9 89 04 00
RSP: 0018:ffffc90000006d98 EFLAGS: 00000046
RAX: ffffed10241cb200 RBX: ffff888120e59000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff888120e59000 RDI: ffff888100042f00
RBP: ffffc90000006dd0 R08: dffffc0000000000 R09: ffffed10241cb200
R10: dffffc0000000000 R11: ffffed10231cb279 R12: 0000000000000001
R13: 0000000000000000 R14: ffff888100042f00 R15: ffffffff819e9930
FS:  00007f6cf027c6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2bf414adac CR3: 0000000111cc1000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:362
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370
 kasan_slab_free include/linux/kasan.h:220 [inline]
 slab_free_hook mm/slub.c:1600 [inline]
 slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1626
 slab_free mm/slub.c:3208 [inline]
 kfree+0xc0/0x270 mm/slub.c:4196
 skb_free_head net/core/skbuff.c:606 [inline]
 skb_release_data+0x53b/0x690 net/core/skbuff.c:626
 skb_release_all net/core/skbuff.c:680 [inline]
 __kfree_skb net/core/skbuff.c:694 [inline]
 kfree_skb+0xb9/0x2f0 net/core/skbuff.c:713
 ip6gre_tunnel_xmit+0xd13/0x1210 net/ipv6/ip6_gre.c:931
 __netdev_start_xmit include/linux/netdevice.h:4864 [inline]
 netdev_start_xmit include/linux/netdevice.h:4878 [inline]
 xmit_one net/core/dev.c:3608 [inline]
 dev_hard_start_xmit+0x245/0x680 net/core/dev.c:3624
 sch_direct_xmit+0x26d/0x990 net/sched/sch_generic.c:339
 qdisc_restart net/sched/sch_generic.c:404 [inline]
 __qdisc_run+0xa3a/0x1400 net/sched/sch_generic.c:412
 qdisc_run+0x100/0x2f0 include/net/pkt_sched.h:126
 __dev_xmit_skb net/core/dev.c:3819 [inline]
 __dev_queue_xmit+0xbc6/0x2500 net/core/dev.c:4175
 dev_queue_xmit+0x17/0x20 net/core/dev.c:4256
 neigh_hh_output include/net/neighbour.h:501 [inline]
 neigh_output include/net/neighbour.h:515 [inline]
 ip6_finish_output2+0xea9/0x1540 net/ipv6/ip6_output.c:130
 __ip6_finish_output+0x5fd/0x790 net/ipv6/ip6_output.c:201
 ip6_finish_output+0x33/0x1e0 net/ipv6/ip6_output.c:211
 NF_HOOK_COND include/linux/netfilter.h:288 [inline]
 ip6_output+0x1fa/0x420 net/ipv6/ip6_output.c:234
 dst_output include/net/dst.h:451 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ndisc_send_skb+0x721/0xbc0 net/ipv6/ndisc.c:513
 ndisc_send_rs+0x711/0x960 net/ipv6/ndisc.c:707
 addrconf_rs_timer+0x35a/0x600 net/ipv6/addrconf.c:3968
 call_timer_fn+0x38/0x290 kernel/time/timer.c:1450
 expire_timers kernel/time/timer.c:1495 [inline]
 __run_timers+0x637/0x9a0 kernel/time/timer.c:1789
 run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1802
 __do_softirq+0x255/0x563 kernel/softirq.c:309
 asm_call_irq_on_stack+0xf/0x20
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline]
 do_softirq_own_stack+0x60/0x80 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:405 [inline]
 __irq_exit_rcu+0x128/0x150 kernel/softirq.c:435
 irq_exit_rcu+0x9/0x10 kernel/softirq.c:447
 sysvec_apic_timer_interrupt+0xbf/0xe0 arch/x86/kernel/apic/apic.c:1106
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:635
RIP: 0010:__local_bh_enable_ip+0x30/0x80 kernel/softirq.c:189
Code: 65 8b 05 af 4e c6 7e a9 00 00 0f 00 75 53 65 8b 05 a1 4e c6 7e ff cf e8 6e b0 08 00 65 8b 05 93 4e c6 7e a9 00 ff ff 00 75 19 <48> c7 c7 80 ae e7 84 e8 24 41 40 03 65 66 8b 05 2c 38 c9 7e 66 85
RSP: 0018:ffffc900013b76a0 EFLAGS: 00000246
RAX: 0000000080000001 RBX: ffff888165878000 RCX: 0000000000000201
RDX: ffffc9000a6bf000 RSI: 0000000000000201 RDI: 00000000fffffe00
RBP: ffffc900013b76a0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000276ec8 R12: dffffc0000000000
R13: 1ffff1102cb0f070 R14: ffff888165878380 R15: 0000000000000000
 __raw_write_unlock_bh include/linux/rwlock_api_smp.h:275 [inline]
 _raw_write_unlock_bh+0x2f/0x48 kernel/locking/spinlock.c:351
 unlist_netdevice+0x2d0/0x380 net/core/dev.c:387
 unregister_netdevice_many+0x49d/0x19f0 net/core/dev.c:10761
 sit_exit_batch_net+0x615/0x660 net/ipv6/sit.c:1943
 ops_exit_list net/core/net_namespace.c:190 [inline]
 setup_net+0x735/0xae0 net/core/net_namespace.c:368
 copy_net_ns+0x314/0x520 net/core/net_namespace.c:486
 create_new_namespaces+0x3a8/0x650 kernel/nsproxy.c:110
 copy_namespaces+0x1cc/0x220 kernel/nsproxy.c:179
 copy_process+0x13b7/0x3320 kernel/fork.c:2271
 kernel_clone+0x233/0x950 kernel/fork.c:2650
 __do_sys_clone kernel/fork.c:2776 [inline]
 __se_sys_clone kernel/fork.c:2760 [inline]
 __x64_sys_clone+0x198/0x210 kernel/fork.c:2760
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f6cf1822e59
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:00007f6cf027bfd8 EFLAGS: 00000202 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007f6cf1aaafa0 RCX: 00007f6cf1822e59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000c0126080
RBP: 00007f6cf18b8e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007f6cf1aab038 R14: 00007f6cf1aaafa0 R15: 00007ffcc1121678

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/02 06:55 android13-5.10-lts 1bb06dbd8c78 27192279 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10-perf BUG: soft lockup in __netif_receive_skb_core
* Struck through repros no longer work on HEAD.