INFO: task syz.3.1562:11538 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.3.1562 state:D stack:28656 pid:11538 tgid:11534 ppid:5601 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x1709/0x5530 kernel/sched/core.c:7231
__schedule_loop kernel/sched/core.c:7308 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7323
cgroup_lock_and_drain_offline+0x51a/0x650 kernel/cgroup/cgroup.c:3275
cgroup_kn_lock_live+0x120/0x230 kernel/cgroup/cgroup.c:1715
cgroup_subtree_control_write+0x4b5/0x1080 kernel/cgroup/cgroup.c:3577
cgroup_file_write+0x331/0x8f0 kernel/cgroup/cgroup.c:4316
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:61 [inline]
do_syscall_64+0x17b/0x530 arch/x86/entry/syscall_64.c:85
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7effa1d8de99
RSP: 002b:00007eff9ffc5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007effa2016090 RCX: 00007effa1d8de99
RDX: 0000000000000005 RSI: 0000200000000040 RDI: 000000000000000b
RBP: 00007effa1e23eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007effa2016128 R14: 00007effa2016090 R15: 00007fff6a7bd7f8
Showing all locks held in the system:
locks held by khungtaskd/38: 1, last CPU#0:
#0: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6835
locks held by kworker/1:1/45: 10, last CPU#1:
#0: ffff8880404c6538 ((wq_completion)wg-crypt-wg0#5){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffff8880404c6538 ((wq_completion)wg-crypt-wg0#5){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffff8880404c6538 ((wq_completion)wg-crypt-wg0#5){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
#1: ffffc90000b67c60 ((work_completion)(&peer->transmit_packet_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffc90000b67c60 ((work_completion)(&peer->transmit_packet_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#1: ffffc90000b67c60 ((work_completion)(&peer->transmit_packet_work)){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
#2: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
#3: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
#4: ffff888059bf4ce0 (&peer->endpoint_lock){++..}-{3:3}, at: read_lock_bh include/linux/rwlock_rt.h:45 [inline]
#4: ffff888059bf4ce0 (&peer->endpoint_lock){++..}-{3:3}, at: wg_socket_send_skb_to_peer+0x6e/0x200 drivers/net/wireguard/socket.c:172
#5: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#5: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#5: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rt_read_lock+0x277/0x4b0 kernel/locking/spinlock_rt.c:251
#6: ffffffff8e259320 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
#7: ffffffff8e3c38e0 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#7: ffffffff8e3c38e0 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:893 [inline]
#7: ffffffff8e3c38e0 (rcu_read_lock_bh){....}-{1:3}, at: send6+0x255/0x920 drivers/net/wireguard/socket.c:118
#8: ffffe8ffffd9d500 ((&({ do { const void *__vpp_verify = (typeof((dst_cache->cache) + 0))((void *)0); (void)__vpp_verify; } while (0); ((typeof((__typeof_unqual__(*((dst_cache->cache))) *)(( unsigned long)((dst_cache->cache)))))((unsigned long)((__typeof_unqual__(*((dst_cache->cache))) *)(( unsigned long)((dst_cache->cache)))) + (((__per_cpu_offset[(i)]))))); })->bh_lock)){+...}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#8: ffffe8ffffd9d500 ((&({ do { const void *__vpp_verify = (typeof((dst_cache->cache) + 0))((void *)0); (void)__vpp_verify; } while (0); ((typeof((__typeof_unqual__(*((dst_cache->cache))) *)(( unsigned long)((dst_cache->cache)))))((unsigned long)((__typeof_unqual__(*((dst_cache->cache))) *)(( unsigned long)((dst_cache->cache)))) + (((__per_cpu_offset[(i)]))))); })->bh_lock)){+...}-{3:3}, at: dst_cache_get_ip6+0xb1/0x260 net/core/dst_cache.c:147
#9: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#9: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#9: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#9: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
locks held by getty/5353: 2, on CPU#1:
#0: ffff8880361f80a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900044c32e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211
locks held by kworker/u8:43/8681: 4, last CPU#1:
#0: ffff8880332dd138 ((wq_completion)bat_events){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffff8880332dd138 ((wq_completion)bat_events){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffff8880332dd138 ((wq_completion)bat_events){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
#1: ffffc9000483fc60 ((work_completion)(&(&forw_packet_aggr->delayed_work)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffc9000483fc60 ((work_completion)(&(&forw_packet_aggr->delayed_work)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#1: ffffc9000483fc60 ((work_completion)(&(&forw_packet_aggr->delayed_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
#2: ffffffff9a00f340 (&obj_hash[i].lock){-...}-{2:2}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#2: ffffffff9a00f340 (&obj_hash[i].lock){-...}-{2:2}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#2: ffffffff9a00f340 (&obj_hash[i].lock){-...}-{2:2}, at: class_rcu_constructor include/linux/rcupdate.h:1183 [inline]
#2: ffffffff9a00f340 (&obj_hash[i].lock){-...}-{2:2}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
#3: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#3: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: nsim_dev_trap_report drivers/net/netdevsim/dev.c:862 [inline]
#3: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: nsim_dev_trap_report_work+0x1e0/0xcb0 drivers/net/netdevsim/dev.c:922
locks held by kworker/u8:46/9261: 5, last CPU#1:
#0: ffff88805927e138 ((wq_completion)wg-kex-wg0#3){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffff88805927e138 ((wq_completion)wg-kex-wg0#3){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffff88805927e138 ((wq_completion)wg-kex-wg0#3){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
#1: ffffc90007d3fc60 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffc90007d3fc60 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#1: ffffc90007d3fc60 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344
#2: ffff8880594697b8 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x12e/0x810 drivers/net/wireguard/noise.c:529
#3: ffff88805ac4e3e0 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x13f/0x810 drivers/net/wireguard/noise.c:530
#4: ffffffff8e259320 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
locks held by syz.3.1562/11538: 3, on CPU#1:
#0: ffff88802be61f28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff888035aee510 (sb_writers#9){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2731 [inline]
#1: ffff888035aee510 (sb_writers#9){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffff88803f61c478 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 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:122
nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65
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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 9261 Comm: kworker/u8:46 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
Workqueue: wg-kex-wg0 wg_packet_handshake_send_worker
RIP: 0010:save_dst_trace_buffer+0x1a2/0x5b0 net/core/dst.c:106
Code: f7 dc 48 89 1c 24 48 8d 9b 60 31 86 9a 48 b8 00 00 00 00 00 fc ff df 41 80 3c 06 00 74 08 48 89 df e8 a2 79 08 f9 48 83 3b 00 <74> 07 e8 b7 22 9c f8 eb 23 48 89 df be 08 00 00 00 e8 28 7c 08 f9
RSP: 0018:ffffc90007d3f480 EFLAGS: 00000286
RAX: dffffc0000000000 RBX: ffffffff9a907020 RCX: ffff888029cebe80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90007d3f608 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc90007d3f3e0 R11: fffff52000fa7e80 R12: e00000000cadf1fb
R13: e00000000cadf1fa R14: 1ffffffff3520e04 R15: e00000000cadf1fa
FS: 0000000000000000(0000) GS:ffff888125af2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055b279b00120 CR3: 000000000e1b0000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
ip6_route_output_flags+0x3df/0x5e0 net/ipv6/route.c:-1
ip6_route_output include/net/ip6_route.h:100 [inline]
ip6_dst_lookup_tail+0x1a1/0x1610 net/ipv6/ip6_output.c:1158
ip6_dst_lookup_flow+0x89/0x150 net/ipv6/ip6_output.c:1291
send6+0x4ea/0x920 drivers/net/wireguard/socket.c:139
wg_socket_send_skb_to_peer+0x128/0x200 drivers/net/wireguard/socket.c:177
wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:40 [inline]
wg_packet_handshake_send_worker+0x204/0x370 drivers/net/wireguard/send.c:51
process_one_work+0xaaf/0x1480 kernel/workqueue.c:3379
process_scheduled_works kernel/workqueue.c:3462 [inline]
worker_thread+0xb05/0x10d0 kernel/workqueue.c:3543
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