INFO: task rcu_tasks_kthre:12 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:rcu_tasks_kthre state:D stack:28224 pid:12 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5246 [inline]
__schedule+0x107f/0x4030 kernel/sched/core.c:6563
schedule+0xb9/0x180 kernel/sched/core.c:6639
schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2144
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x2c2/0x590 kernel/sched/completion.c:138
__synchronize_srcu+0x2b3/0x350 kernel/rcu/srcutree.c:1243
rcu_tasks_wait_gp+0x49f/0xac0 kernel/rcu/tasks.h:693
rcu_tasks_one_gp+0xd27/0xef0 kernel/rcu/tasks.h:534
rcu_tasks_kthread+0x6e/0x90 kernel/rcu/tasks.h:562
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2e230 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2ea50 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
2 locks held by kworker/1:1/27:
#0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90000a3fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
1 lock held by khungtaskd/28:
#0: ffffffff8cb2d8a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2d8a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2d8a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6669
2 locks held by getty/4028:
#0: ffff88814e088098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198
2 locks held by kworker/u4:18/9883:
1 lock held by syz.2.3286/15546:
3 locks held by kworker/u4:3/16043:
#0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc900037e7d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:263
3 locks held by kworker/1:6/17474:
#0: ffff88814d1acd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc9000c9afd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x1500 net/ipv6/addrconf.c:4146
3 locks held by syz.5.4558/19392:
#0: ffffffff8dcbf288 (register_mutex#4){+.+.}-{3:3}, at: odev_release+0x4a/0x70 sound/core/seq/oss/seq_oss.c:143
#1: ffff8880747b04b8 (&mdev->open_mutex){+.+.}-{3:3}, at: snd_seq_oss_midi_close+0x193/0x6c0 sound/core/seq/oss/seq_oss_midi.c:404
#2: ffff888079e1c9f0 (&grp->list_mutex#2){++++}-{3:3}, at: snd_seq_port_disconnect+0x53/0x660 sound/core/seq/seq_ports.c:612
2 locks held by syz.3.4567/19418:
2 locks held by syz.6.4568/19419:
#0: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
#0: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3506
#1: ffffffff8cb33578 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
#1: ffffffff8cb33578 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962
1 lock held by syz.7.4569/19425:
#0: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
#0: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x80d/0xfb0 net/core/rtnetlink.c:6163
1 lock held by syz.7.4569/19429:
#0: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
#0: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x80d/0xfb0 net/core/rtnetlink.c:6163
1 lock held by syz.1.4570/19427:
#0: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
#0: ffffffff8dd56d68 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x80d/0xfb0 net/core/rtnetlink.c:6163
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xf0e/0xf50 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 15 Comm: ksoftirqd/0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:stackdepot_memcmp lib/stackdepot.c:290 [inline]
RIP: 0010:find_stack lib/stackdepot.c:306 [inline]
RIP: 0010:__stack_depot_save+0x179/0x480 lib/stackdepot.c:452
Code: 21 ef 4f 8b 2c f9 4d 85 ed 74 63 89 ca eb 09 4d 8b 6d 00 4d 85 ed 74 56 41 39 6d 08 75 f1 41 39 4d 0c 75 eb 31 f6 49 8b 3c f6 <49> 3b 7c f5 18 75 de 48 ff c6 39 f2 75 ee 4d 85 ed 74 09 b8 ff ff
RSP: 0018:ffffc90000147678 EFLAGS: 00000002
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000000000000c
RDX: 000000000000000c RSI: 000000000000000b RDI: ffffffff81004bbf
RBP: 00000000b72caa93 R08: 0000000000000800 R09: ffff88823b400000
R10: 000000004f1620b9 R11: 00000000b3829398 R12: 0000000000000000
R13: ffff8880785202c0 R14: ffffc900001476e0 R15: 00000000000caa93
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3b2237 CR3: 000000008bd40000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
kasan_save_stack+0x4c/0x60 mm/kasan/common.c:47
__kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486
insert_work+0x54/0x3c0 kernel/workqueue.c:1361
__queue_work+0xae2/0xee0 kernel/workqueue.c:1520
call_timer_fn+0x1ac/0x670 kernel/time/timer.c:1701
expire_timers kernel/time/timer.c:1747 [inline]
__run_timers+0x598/0x810 kernel/time/timer.c:2023
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
handle_softirqs+0x291/0x910 kernel/softirq.c:596
run_ksoftirqd+0xa4/0x100 kernel/softirq.c:968
smpboot_thread_fn+0x667/0xa30 kernel/smpboot.c:164
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295