syzbot


BUG: soft lockup in sys_clone (3)

Status: premoderation: reported on 2026/02/01 19:31
Reported-by: syzbot+6cdd1a03b3b69d2fc9b8@syzkaller.appspotmail.com
First crash: 4d04h, last: 4d04h
Similar bugs (15)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-10 BUG: soft lockup in sys_clone 1 1 577d 577d 0/2 auto-obsoleted due to no activity on 2024/10/06 12:58
upstream BUG: soft lockup in sys_clone kernel 1 3 2141d 2145d 0/29 closed as invalid on 2020/05/29 21:04
android-5-10 BUG: soft lockup in sys_clone (2) 1 1 151d 151d 0/2 auto-obsoleted due to no activity on 2025/12/06 02:03
upstream INFO: rcu detected stall in sys_clone (8) mm 1 C error 374 1d21h 679d 0/29 upstream: reported C repro on 2024/03/29 00:16
linux-5.15 INFO: rcu detected stall in sys_clone (2) missing-backport origin:upstream 1 C done 77 2d17h 681d 0/3 upstream: reported C repro on 2024/03/27 00:16
android-5-15 BUG: soft lockup in sys_clone origin:upstream 1 C error 18 513d 656d 0/2 auto-obsoleted due to no activity on 2024/12/19 12:14
linux-6.6 INFO: rcu detected stall in sys_clone 1 C done 8 92d 177d 2/2 fixed on 2025/12/06 23:11
linux-5.15 INFO: rcu detected stall in sys_clone 1 1 792d 792d 0/3 auto-obsoleted due to no activity on 2024/03/15 18:08
linux-6.1 INFO: rcu detected stall in sys_clone 1 3 939d 1011d 0/3 auto-obsoleted due to no activity on 2023/10/20 18:18
upstream INFO: rcu detected stall in sys_clone (4) kernel 1 1 1682d 1682d 0/29 auto-closed as invalid on 2021/09/27 17:49
upstream INFO: rcu detected stall in sys_clone (6) kasan mm 1 1 1352d 1352d 0/29 auto-closed as invalid on 2022/08/23 03:28
upstream INFO: rcu detected stall in sys_clone (5) kernfs 1 5 1487d 1586d 0/29 closed as invalid on 2022/02/08 10:00
upstream INFO: rcu detected stall in sys_clone (7) fs 1 1 1088d 1088d 0/29 auto-obsoleted due to no activity on 2023/05/14 17:18
linux-6.1 INFO: rcu detected stall in sys_clone (2) origin:upstream missing-backport 1 C error 41 15d 687d 0/3 upstream: reported C repro on 2024/03/20 15:17
linux-6.6 INFO: rcu detected stall in sys_clone (2) 1 6 11d 58d 0/2 upstream: reported on 2025/12/09 09:13

Sample crash report:
watchdog: BUG: soft lockup - CPU#1 stuck for 123s! [syz.2.15379:20712]
Modules linked in:
CPU: 1 PID: 20712 Comm: syz.2.15379 Tainted: G        W         syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:434 [inline]
RIP: 0010:__pv_queued_spin_lock_slowpath+0x584/0xb70 kernel/locking/qspinlock.c:508
Code: 00 00 41 c6 06 00 48 8b 44 24 10 42 0f b6 04 38 84 c0 0f 85 c4 01 00 00 48 8b 44 24 08 c6 00 01 41 be 00 80 ff ff eb 07 f3 90 <41> ff c6 74 4b 43 0f b6 44 3d 00 84 c0 75 2e 80 3b 00 75 ea 48 89
RSP: 0018:ffffc90000b775e0 EFLAGS: 00000206
RAX: 0000000000000004 RBX: ffffffff86ed8780 RCX: 0000000086ed8700
RDX: 0000000000000001 RSI: 0000000000000003 RDI: ffffffff86ed8780
RBP: ffffc90000b776d0 R08: 0000000000000000 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff0ddb0f0 R12: ffff88823ff92680
R13: 1ffffffff0ddb0f0 R14: 00000000fffff70a R15: dffffc0000000000
FS:  00007f5a1f02d6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5a2061e600 CR3: 0000000121881000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000200000000300
DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:554 [inline]
 queued_spin_lock_slowpath+0x47/0x50 arch/x86/include/asm/qspinlock.h:51
 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline]
 do_raw_spin_lock include/linux/spinlock.h:184 [inline]
 __raw_spin_lock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_lock+0xe4/0xf0 kernel/locking/spinlock.c:151
 spin_lock include/linux/spinlock.h:355 [inline]
 __register_sysctl_table+0x7e7/0x1250 fs/proc/proc_sysctl.c:1333
 register_net_sysctl+0x2c/0x40 net/sysctl_net.c:121
 netfilter_log_sysctl_init net/netfilter/nf_log.c:501 [inline]
 nf_log_net_init+0x4ca/0x590 net/netfilter/nf_log.c:550
 ops_init+0x1ba/0x4a0 net/core/net_namespace.c:144
 setup_net+0x376/0xb60 net/core/net_namespace.c:345
 copy_net_ns+0x314/0x520 net/core/net_namespace.c:486
 create_new_namespaces+0x3a2/0x650 kernel/nsproxy.c:110
 copy_namespaces+0x1d1/0x220 kernel/nsproxy.c:179
 copy_process+0x11d3/0x3300 kernel/fork.c:2271
 kernel_clone+0x233/0x960 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: 0033:0x7f5a205d0eb9
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:00007f5a1f02cfd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007f5a2084bfa0 RCX: 00007f5a205d0eb9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000630c1000
RBP: 00007f5a2063ec1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f5a2084c038 R14: 00007f5a2084bfa0 R15: 00007ffeaa43b708
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 20627 Comm: syz.6.15353 Tainted: G        W         syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:25 [inline]
RIP: 0010:static_key_false include/linux/jump_label.h:221 [inline]
RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:162 [inline]
RIP: 0010:wrmsr arch/x86/include/asm/msr.h:273 [inline]
RIP: 0010:native_apic_msr_write+0x39/0x50 arch/x86/include/asm/apic.h:208
Code: 74 05 83 ff 30 75 12 5d c3 81 ff d0 00 00 00 74 f6 81 ff e0 00 00 00 74 ee c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <e9> 02 00 00 00 eb d6 89 f6 31 d2 e8 07 51 2b 01 5d c3 0f 1f 44 00
RSP: 0018:ffffc90000007208 EFLAGS: 00000046
RAX: 00000000000000d4 RBX: 00000000000000d4 RCX: 0000000000000838
RDX: 0000000000000000 RSI: 00000000000000d4 RDI: 0000000000000838
RBP: ffffc90000007208 R08: ffff88811f874f00 R09: 0000000000000002
R10: 0000000000000003 R11: 0000000000010101 R12: ffff8881f7026ea8
R13: ffff8881f7026e88 R14: ffffffff85bf6998 R15: dffffc0000000000
FS:  00007f8bbcd376c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000100000000 CR3: 000000010bd77000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 apic_write arch/x86/include/asm/apic.h:396 [inline]
 lapic_next_event+0x5f/0x70 arch/x86/kernel/apic/apic.c:466
 clockevents_program_event+0x1fa/0x8b0 kernel/time/clockevents.c:334
 tick_program_event+0xa3/0x120 kernel/time/tick-oneshot.c:44
 hrtimer_interrupt+0x3f9/0xdc0 kernel/time/hrtimer.c:1726
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1095 [inline]
 __sysvec_apic_timer_interrupt+0xfa/0x3f0 arch/x86/kernel/apic/apic.c:1112
 run_sysvec_on_irqstack_cond arch/x86/include/asm/irq_stack.h:91 [inline]
 sysvec_apic_timer_interrupt+0xba/0xe0 arch/x86/kernel/apic/apic.c:1106
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:635
RIP: 0010:update_stack_state+0x3d7/0x480 arch/x86/kernel/unwind_frame.c:252
Code: 8b 05 ad 36 d3 7e 49 39 45 00 74 0e 48 8b 7d d0 e8 2e fc ff ff 49 89 c6 eb 1d 4c 8b 75 d0 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 <74> 08 4c 89 f7 e8 6f fc 6f 00 4d 8b 36 48 83 c3 48 48 89 d8 48 c1
RSP: 0018:ffffc90000007538 EFLAGS: 00000246
RAX: 1ffff92000000fc7 RBX: ffffc90000007688 RCX: ffffc90000007e01
RDX: ffffc90000007e30 RSI: 1ffff92000000ed2 RDI: ffffc900000076e0
RBP: ffffc900000075f8 R08: ffffc90000007750 R09: ffffc90000007748
R10: 000000000000000c R11: fffff52000000edd R12: dffffc0000000000
R13: ffffc900000076b0 R14: ffffc90000007e38 R15: 1ffff92000000ed9
 unwind_next_frame+0x3d5/0x700 arch/x86/kernel/unwind_frame.c:316
 arch_stack_walk+0x108/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:121
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4a/0x70 mm/kasan/common.c:45
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
 ____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]
 kmem_cache_free+0x100/0x2d0 mm/slub.c:3224
 kfree_skbmem+0x10c/0x180 net/core/skbuff.c:-1
 __kfree_skb net/core/skbuff.c:695 [inline]
 kfree_skb+0xc1/0x2f0 net/core/skbuff.c:713
 ip6_mc_input+0x235/0x2a0 net/ipv6/ip6_input.c:574
 dst_input include/net/dst.h:461 [inline]
 ip6_rcv_finish+0x18c/0x360 net/ipv6/ip6_input.c:80
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ipv6_rcv+0xf0/0x230 net/ipv6/ip6_input.c:301
 __netif_receive_skb_one_core net/core/dev.c:5402 [inline]
 __netif_receive_skb+0xc8/0x280 net/core/dev.c:5516
 process_backlog+0x368/0x600 net/core/dev.c:6423
 napi_poll net/core/dev.c:6874 [inline]
 net_rx_action+0x44d/0xe00 net/core/dev.c:6944
 __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:erase_header fs/proc/proc_sysctl.c:214 [inline]
RIP: 0010:start_unregistering fs/proc/proc_sysctl.c:306 [inline]
RIP: 0010:drop_sysctl_table+0x241/0x430 fs/proc/proc_sysctl.c:1680
Code: 01 00 48 8b 5c 24 38 74 08 48 89 df e8 d8 c7 d8 ff 49 d1 fc 4d 01 e6 48 8b 33 48 83 c6 50 4c 89 f7 e8 a3 d7 94 00 49 83 c7 40 <4c> 89 f8 48 c1 e8 03 49 bc 00 00 00 00 00 fc ff df 42 80 3c 20 00
RSP: 0018:ffffc90001437460 EFLAGS: 00000282
RAX: 1ffff11028f15e6a RBX: ffff8881478af038 RCX: dffffc0000000000
RDX: ffffc9000a435000 RSI: ffff88811da41a50 RDI: ffff8881478af338
RBP: ffffc90001437558 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000286e7c R12: 00000000000002e0
R13: ffff88814c526608 R14: ffff8881478af330 R15: ffff88814c526608
 unregister_sysctl_table+0x75/0x120 fs/proc/proc_sysctl.c:1722
 unregister_net_sysctl_table+0x15/0x20 net/sysctl_net.c:127
 __devinet_sysctl_unregister net/ipv4/devinet.c:2621 [inline]
 devinet_sysctl_unregister net/ipv4/devinet.c:2649 [inline]
 inetdev_destroy net/ipv4/devinet.c:326 [inline]
 inetdev_event+0x7b1/0x1040 net/ipv4/devinet.c:1612
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0x90/0x100 kernel/notifier.c:410
 call_netdevice_notifiers_info net/core/dev.c:2054 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2066 [inline]
 call_netdevice_notifiers net/core/dev.c:2080 [inline]
 unregister_netdevice_many+0x1074/0x1a80 net/core/dev.c:10767
 sit_exit_batch_net+0x60f/0x660 net/ipv6/sit.c:1943
 ops_exit_list net/core/net_namespace.c:190 [inline]
 setup_net+0x799/0xb60 net/core/net_namespace.c:368
 copy_net_ns+0x314/0x520 net/core/net_namespace.c:486
 create_new_namespaces+0x3a2/0x650 kernel/nsproxy.c:110
 copy_namespaces+0x1d1/0x220 kernel/nsproxy.c:179
 copy_process+0x11d3/0x3300 kernel/fork.c:2271
 kernel_clone+0x233/0x960 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: 0033:0x7f8bbe2daeb9
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:00007f8bbcd36fd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007f8bbe555fa0 RCX: 00007f8bbe2daeb9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 00007f8bbe348c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f8bbe556038 R14: 00007f8bbe555fa0 R15: 00007ffdc3c59248

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/01 19:30 android13-5.10-lts 186f761c519d 6b8752f2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10-perf BUG: soft lockup in sys_clone
* Struck through repros no longer work on HEAD.