INFO: task syz-executor:20816 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:18224 pid:20816 tgid:20816 ppid:1 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5504 [inline]
__schedule+0x16dc/0x5500 kernel/sched/core.c:7228
__schedule_loop kernel/sched/core.c:7307 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7603
rt_mutex_slowlock_block+0x55c/0x680 kernel/locking/rtmutex.c:1670
__rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline]
rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827
__rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline]
mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578
del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234
kernfs_fop_write_iter+0x3a5/0x540 fs/kernfs/file.c:345
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x61e/0xbb0 fs/read_write.c:687
ksys_write+0x156/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcdb478d68e
RSP: 002b:00007ffd0cb0fcf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000055555ac2b500 RCX: 00007fcdb478d68e
RDX: 0000000000000001 RSI: 00007ffd0cb0fd80 RDI: 0000000000000005
RBP: 00007fcdb48636f2 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffd0cb0fd80 R14: 00007fcdb5574620 R15: 0000000000000003
INFO: lockdep is turned off.
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xfd7/0x1030 kernel/hung_task.c:561
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 16 Comm: ktimers/0 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:101 [inline]
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:238 [inline]
RIP: 0010:unwind_next_frame+0x4c6/0x2550 arch/x86/kernel/unwind_orc.c:510
Code: 6c 24 50 49 bc 00 00 00 00 00 fc ff df 4c 8b 7c 24 10 49 8d 6e 38 0f 84 8a 16 00 00 e9 ee 01 00 00 49 89 d5 49 89 d7 4c 89 e0 <4c> 29 f8 48 89 c1 48 c1 f9 02 48 c1 e8 3f 48 01 c8 48 83 e0 fe 49
RSP: 0018:ffffc90000156840 EFLAGS: 00000283
RAX: ffffffff8ff88f28 RBX: ffffffff8ff88f18 RCX: ffffffff8ff88f1c
RDX: ffffffff8ff88f0c RSI: ffffffff9099fe14 RDI: ffffffff8ba7f040
RBP: ffffffff89432fc4 R08: 0000000000000008 R09: 0000000000000000
R10: ffffc90000156938 R11: ffffffff81afe1e0 R12: ffffffff8ff88f28
R13: ffffffff8ff88f18 R14: ffffc900001568e8 R15: ffffffff8ff88f1c
FS: 0000000000000000(0000) GS:ffff888126144000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6262b7d2fd CR3: 000000009b86a000 CR4: 00000000003526f0
Call Trace:
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2700 [inline]
slab_free mm/slub.c:6310 [inline]
kmem_cache_free+0x187/0x6c0 mm/slub.c:6437
skb_ext_reset include/linux/skbuff.h:5119 [inline]
skb_release_head_state+0x270/0x360 net/core/skbuff.c:1183
skb_release_all net/core/skbuff.c:1189 [inline]
__kfree_skb+0x24/0x210 net/core/skbuff.c:1205
kfree_skb_reason include/linux/skbuff.h:1325 [inline]
kfree_skb include/linux/skbuff.h:1334 [inline]
ip6_mc_input+0x909/0xbc0 net/ipv6/ip6_input.c:638
ip_sabotage_in+0x1e1/0x270 net/bridge/br_netfilter_hooks.c:988
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619
nf_hook include/linux/netfilter.h:273 [inline]
NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:316
__netif_receive_skb_one_core net/core/dev.c:6206 [inline]
__netif_receive_skb net/core/dev.c:6319 [inline]
netif_receive_skb_internal net/core/dev.c:6405 [inline]
netif_receive_skb+0x278/0xbf0 net/core/dev.c:6464
NF_HOOK+0xa4/0x3a0 include/linux/netfilter.h:318
br_handle_frame_finish+0x1192/0x1990 net/bridge/br_input.c:-1
br_nf_hook_thresh+0x3dd/0x4c0 net/bridge/br_netfilter_hooks.c:-1
br_nf_pre_routing_finish_ipv6+0x90c/0xc40 net/bridge/br_netfilter_ipv6.c:-1
NF_HOOK include/linux/netfilter.h:318 [inline]
br_nf_pre_routing_ipv6+0x382/0x6f0 net/bridge/br_netfilter_ipv6.c:183
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_bridge_pre net/bridge/br_input.c:291 [inline]
br_handle_frame+0x1282/0x1520 net/bridge/br_input.c:442
__netif_receive_skb_core+0x989/0x30b0 net/core/dev.c:6093
__netif_receive_skb_one_core net/core/dev.c:6204 [inline]
__netif_receive_skb net/core/dev.c:6319 [inline]
process_backlog+0x351/0xc50 net/core/dev.c:6670
__napi_poll+0xae/0x550 net/core/dev.c:7729
napi_poll net/core/dev.c:7792 [inline]
net_rx_action+0x621/0xd70 net/core/dev.c:7949
handle_softirqs+0x1d9/0x6c0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
run_ktimerd+0x69/0x100 kernel/softirq.c:1151
smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245