INFO: rcu detected stall in skb_release_data (2)

Status: upstream: reported on 2026/10/18 20:41
Reported-by: syzbot+bc3ece1de533e9b6b924@syzkaller.appspotmail.com
First crash: 25d, last: 25d
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in skb_release_data fs mm 1 1 1895d 1895d 0/29 auto-closed as invalid on 2021/12/04 08:37
linux-5.15 INFO: rcu detected stall in skb_release_data 1 1 773d 773d 0/3 auto-obsoleted due to no activity on 2025/01/08 15:07
linux-6.1 INFO: rcu detected stall in skb_release_data 1 1 162d 162d 0/3 auto-obsoleted due to no activity on 2026/09/12 10:19
linux-4.19 BUG: soft lockup in skb_release_data 1 1 1366d 1366d 0/1 upstream: reported on 2023/02/15 16:04

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 1-.... } 3299 jiffies s: 1689181 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: 17714 Comm: syz.4.3202 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:perf_trace_buf_alloc+0xc1/0x300 kernel/trace/trace_event_perf.c:419
Code: fd 04 0f 87 27 02 00 00 e8 1c e6 f7 ff 4c 89 3c 24 4d 69 ff a8 00 00 00 e8 ec 9d a9 08 41 89 c5 41 89 c4 bf 08 00 00 00 89 c6 <e8> 5a e9 f7 ff 41 83 fd 07 0f 87 0f 02 00 00 e8 eb e5 f7 ff 49 bd
RSP: 0018:ffffc900001dfda0 EFLAGS: 00000086
RAX: 0000000000000001 RBX: 0000000000000034 RCX: d613b59383f8c200
RDX: 0000000000010100 RSI: 0000000000000001 RDI: 0000000000000008
RBP: 0000000000000002 R08: ffffffff8f00d22f R09: 1ffffffff1e01a45
R10: dffffc0000000000 R11: fffffbfff1e01a46 R12: 0000000000000001
R13: 0000000000000001 R14: ffffc900001dfe40 R15: 0000000000000150
FS:  00007fec678d46c0(0000) GS:ffff8880b8d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31e23ffc CR3: 0000000079f26000 CR4: 00000000003506e0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 perf_trace_lock+0x19c/0x390 include/trace/events/lock.h:50
 trace_lock_release include/trace/events/lock.h:69 [inline]
 lock_release+0x8ad/0x920 kernel/locking/lockdep.c:5801
 seqcount_lockdep_reader_access+0xe0/0x1d0 include/linux/seqlock.h:103
 ktime_get+0x31/0x270 kernel/time/timekeeping.c:846
 hrtimer_forward_now include/linux/hrtimer.h:509 [inline]
 perf_swevent_hrtimer+0x4f8/0x630 kernel/events/core.c:10982
 __run_hrtimer kernel/time/hrtimer.c:1751 [inline]
 __hrtimer_run_queues+0x4e7/0xc90 kernel/time/hrtimer.c:1815
 hrtimer_interrupt+0x399/0x980 kernel/time/hrtimer.c:1877
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
 __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1118
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [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> ff b7 1a f7 65 8b 05 c0 67 c4 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc900001e06a0 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a06 RCX: d613b59383f8c200
RDX: dffffc0000000000 RSI: ffffffff8a8c19a0 RDI: 0000000000000001
RBP: ffffc900001e0738 R08: ffffffff919342df R09: 1ffffffff232685b
R10: dffffc0000000000 R11: fffffbfff232685c R12: dffffc0000000000
R13: ffff888057831600 R14: ffffffff97c48850 R15: 1ffff9200003c0d4
 __debug_check_no_obj_freed lib/debugobjects.c:1054 [inline]
 debug_check_no_obj_freed+0x471/0x520 lib/debugobjects.c:1075
 slab_free_hook mm/slub.c:1704 [inline]
 slab_free_freelist_hook+0xd2/0x1b0 mm/slub.c:1755
 slab_free mm/slub.c:3687 [inline]
 __kmem_cache_free+0xb6/0x200 mm/slub.c:3700
 skb_free_head net/core/skbuff.c:762 [inline]
 skb_release_data+0x5e9/0x7e0 net/core/skbuff.c:791
 skb_release_all net/core/skbuff.c:856 [inline]
 __kfree_skb net/core/skbuff.c:870 [inline]
 kfree_skb_reason+0x163/0x370 net/core/skbuff.c:893
 __netif_receive_skb_core+0x3217/0x38c0 net/core/dev.c:5594
 __netif_receive_skb_one_core net/core/dev.c:5618 [inline]
 __netif_receive_skb+0x74/0x290 net/core/dev.c:5734
 process_backlog+0x37c/0x710 net/core/dev.c:6062
 __napi_poll+0xbb/0x460 net/core/dev.c:6629
 napi_poll net/core/dev.c:6696 [inline]
 net_rx_action+0x622/0xbc0 net/core/dev.c:6810
 handle_softirqs+0x291/0x910 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: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 68 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:ffffc90004ccf0a0 EFLAGS: 00000206
RAX: d613b59383f8c200 RBX: 1ffff92000999e1c RCX: d613b59383f8c200
RDX: dffffc0000000000 RSI: ffffffff8a8c19a0 RDI: ffffffff8adf7160
RBP: ffffc90004ccf1a0 R08: ffffffff919342df R09: 1ffffffff232685b
R10: dffffc0000000000 R11: fffffbfff232685c R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8d3bb00 R15: 0000000000000002
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 trace_call_bpf+0x5bb/0x6b0 kernel/trace/bpf_trace.c:137
 perf_trace_run_bpf_submit+0x79/0x1c0 kernel/events/core.c:10037
 perf_trace_lock+0x301/0x390 include/trace/events/lock.h:50
 trace_lock_release include/trace/events/lock.h:69 [inline]
 lock_release+0x8ad/0x920 kernel/locking/lockdep.c:5801
 page_table_check_pte_set include/linux/page_table_check.h:83 [inline]
 set_pte_at arch/x86/include/asm/pgtable.h:1009 [inline]
 copy_present_pte mm/memory.c:1000 [inline]
 copy_pte_range mm/memory.c:1091 [inline]
 copy_pmd_range mm/memory.c:1177 [inline]
 copy_pud_range mm/memory.c:1214 [inline]
 copy_p4d_range mm/memory.c:1238 [inline]
 copy_page_range+0x2586/0x3a60 mm/memory.c:1332
 dup_mmap kernel/fork.c:703 [inline]
 dup_mm kernel/fork.c:1552 [inline]
 copy_mm+0xeb0/0x1680 kernel/fork.c:1601
 copy_process+0x1952/0x4070 kernel/fork.c:2358
 kernel_clone+0x24b/0x900 kernel/fork.c:2765
 __do_sys_clone kernel/fork.c:2906 [inline]
 __se_sys_clone kernel/fork.c:2890 [inline]
 __x64_sys_clone+0x1a7/0x220 kernel/fork.c:2890
 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: 0033:0x7fec6699e559
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:00007fec678d3fd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007fec66c25fa0 RCX: 00007fec6699e559
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000011
RBP: 00007fec66a35ab8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007fec66c26038 R14: 00007fec66c25fa0 R15: 00007ffc05c0fe28
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/18 20:41 linux-6.1.y 79807e970724 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in skb_release_data
* Struck through repros no longer work on HEAD.