INFO: rcu detected stall in packet_rcv

Status: upstream: reported on 2026/10/25 18:19
Reported-by: syzbot+81ca9553dc9246ad28bd@syzkaller.appspotmail.com
First crash: 18d, last: 18d
▶ ▼ Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in packet_rcv (2) 1 1 11d 11d 0/3 upstream: reported on 2026/11/02 09:41
upstream INFO: rcu detected stall in packet_rcv (2) net 1 1 1053d 1053d 0/29 auto-obsoleted due to no activity on 2024/03/25 03:49
upstream INFO: rcu detected stall in packet_rcv net 1 1 1850d 1850d 0/29 auto-closed as invalid on 2021/12/19 00:49
upstream INFO: rcu detected stall in packet_rcv (3) net bpf 1 4 820d 845d 0/29 auto-obsoleted due to no activity on 2024/11/13 10:03
linux-6.1 INFO: rcu detected stall in packet_rcv 1 1 137d 137d 0/3 auto-obsoleted due to no activity on 2026/10/06 16:32
android-6-1 BUG: soft lockup in packet_rcv 1 1 186d 186d 0/2 auto-obsoleted due to no activity on 2026/08/08 15:43
upstream BUG: soft lockup in packet_rcv perf trace 1 2 320d 372d 0/29 closed as invalid on 2026/02/11 22:39

Sample crash report:
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (1 GPs behind) idle=f2b/1/0x4000000000000000 softirq=14571/14575 fqs=4355 
	(t=10500 jiffies g=18105 q=1304)
NMI backtrace for cpu 1
CPU: 1 PID: 7310 Comm: syz.3.624 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
 <IRQ>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_dump_cpu_stacks+0x22d/0x380 kernel/rcu/tree_stall.h:349
 print_cpu_stall+0x31f/0x5f0 kernel/rcu/tree_stall.h:633
 check_cpu_stall kernel/rcu/tree_stall.h:727 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x6ec/0x1120 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:2021
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4b0/0xb60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x397/0x8b0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1108
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:lock_acquire+0x209/0x400 kernel/locking/lockdep.c:5741
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc90000dd05a0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 3f2c3b3833504f00
RDX: 0000000000000000 RSI: ffffffff8a2b3e00 RDI: ffffffff8a7a4bc0
RBP: ffffc90000dd06c0 R08: dffffc0000000000 R09: 1ffffffff2208c18
R10: dffffc0000000000 R11: fffffbfff2208c19 R12: 1ffff920001ba0c0
R13: ffffffff8d11efa0 R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 run_filter+0x1f/0x220 net/packet/af_packet.c:2116
 packet_rcv+0x3cc/0x1260 net/packet/af_packet.c:2192
 deliver_skb net/core/dev.c:2278 [inline]
 __netif_receive_skb_core+0x671/0x3670 net/core/dev.c:5398
 __netif_receive_skb_list_core+0x24d/0x770 net/core/dev.c:5628
 __netif_receive_skb_list net/core/dev.c:5695 [inline]
 netif_receive_skb_list_internal+0x898/0xbd0 net/core/dev.c:5786
 netif_receive_skb_list+0x50/0x3e0 net/core/dev.c:5838
 ieee80211_rx_napi+0x349/0x390 net/mac80211/rx.c:5024
 ieee80211_rx include/net/mac80211.h:4573 [inline]
 ieee80211_handle_queued_frames+0x104/0x1a0 net/mac80211/main.c:237
 tasklet_action_common+0x2ad/0x410 kernel/softirq.c:806
 handle_softirqs+0x336/0x830 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:preempt_schedule_irq+0xb6/0x160 kernel/sched/core.c:6799
Code: 00 00 43 c6 44 37 04 f8 74 0b 0f 0b 48 f7 03 08 00 00 00 74 7f bf 01 00 00 00 e8 85 3d 81 f7 e8 00 35 ae f7 fb bf 01 00 00 00 <e8> d5 b5 ff ff 43 c6 44 37 08 00 48 c7 44 24 40 00 00 00 00 9c 8f
RSP: 0018:ffffc9000341fae0 EFLAGS: 00000282
RAX: 3f2c3b3833504f00 RBX: 0000000000000000 RCX: 3f2c3b3833504f00
RDX: dffffc0000000000 RSI: ffffffff8a2b2b60 RDI: 0000000000000001
RBP: ffffc9000341fb90 R08: ffffffff8ff3b048 R09: ffffffff8ff3b058
R10: ffffffff8ff3b050 R11: ffffffff8ff3b043 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff92000683f5c
 irqentry_exit+0x63/0x70 kernel/entry/common.c:435
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:64
Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 <f3> aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01
RSP: 0018:ffffc9000341fc58 EFLAGS: 00010246
RAX: ffff88807878e800 RBX: 0000000000000000 RCX: 00000000000004c0
RDX: 0000000000000780 RSI: 0000000000000000 RDI: ffff88807878eac0
RBP: 0000000000000001 R08: 000000000000000c R09: ffff88807878e800
R10: 0000000000000003 R11: 00000000f96a895d R12: 0000000000000001
R13: ffff88801e141dc0 R14: 0000000000000cc0 R15: ffffc9000341fcc8
 slab_post_alloc_hook+0x68/0x380 mm/slab.h:521
 slab_alloc_node mm/slub.c:3225 [inline]
 slab_alloc mm/slub.c:3233 [inline]
 kmem_cache_alloc+0x15d/0x280 mm/slub.c:3238
 sk_prot_alloc+0x57/0x210 net/core/sock.c:1859
 sk_alloc+0x2f/0x310 net/core/sock.c:1921
 unix_create1+0xad/0x610 net/unix/af_unix.c:-1
 unix_create+0x139/0x1f0 net/unix/af_unix.c:929
 __sock_create+0x473/0x910 net/socket.c:1496
 sock_create net/socket.c:1552 [inline]
 __sys_socketpair+0x232/0x540 net/socket.c:1656
 __do_sys_socketpair net/socket.c:1705 [inline]
 __se_sys_socketpair net/socket.c:1702 [inline]
 __x64_sys_socketpair+0x97/0xb0 net/socket.c:1702
 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: 0033:0x7f762c544559
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:00007f762a759028 EFLAGS: 00000246 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 00007f762c7cb180 RCX: 00007f762c544559
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
RBP: 00007f762c5dbb20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000000800 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f762c7cb218 R14: 00007f762c7cb180 R15: 00007ffd4030fad8
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/25 18:18 linux-5.15.y 792fbe1537d8 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in packet_rcv
* Struck through repros no longer work on HEAD.