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:28256 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: ffffffff8cb2e4f0 (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: ffffffff8cb2ed10 (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/0:1/14:
#0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90000137d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
1 lock held by khungtaskd/28:
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6527
2 locks held by getty/4031:
#0: ffff88814ddf0098 (&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
4 locks held by kworker/u4:24/29343:
#0: ffff88801761e938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc9000caefd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8dd4f610 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:594
#3: ffffffff8dd5c4a8 (rtnl_mutex){+.+.}-{3:3}, at: bareudp_exit_batch_net+0xb8/0x200 drivers/net/bareudp.c:787
1 lock held by syz.0.11208/5737:
1 lock held by syz.4.11228/5790:
#0: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
#0: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962
2 locks held by syz.0.11242/5829:
2 locks held by syz.0.11256/5881:
3 locks held by syz.1.11271/5925:
1 lock held by syz.0.11297/6006:
#0: ffffffff8dd5c4a8 (rtnl_mutex){+.+.}-{3:3}, at: __netlink_dump_start+0x11e/0x6f0 net/netlink/af_netlink.c:2310
2 locks held by syz.4.11298/5998:
#0: ffffffff8dd5c4a8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
#0: ffffffff8dd5c4a8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3495
#1: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
#1: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962
1 lock held by syz.5.11300/6009:
#0: ffffffff8dd5c4a8 (rtnl_mutex){+.+.}-{3:3}, at: ip_rt_ioctl+0x102/0x1180 net/ipv4/fib_frontend.c:630
1 lock held by syz.1.11304/6021:
#0: ffffffff8dd5c4a8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
#0: ffffffff8dd5c4a8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3495
2 locks held by syz.1.11304/6023:
#0: ffffffff8d5b0148 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0xdc/0x1b20 drivers/net/ppp/ppp_generic.c:727
#1: ffffffff8dd5c4a8 (rtnl_mutex){+.+.}-{3:3}, at: ppp_create_interface drivers/net/ppp/ppp_generic.c:3376 [inline]
#1: ffffffff8dd5c4a8 (rtnl_mutex){+.+.}-{3:3}, at: ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1065 [inline]
#1: ffffffff8dd5c4a8 (rtnl_mutex){+.+.}-{3:3}, at: ppp_ioctl+0x8db/0x1b20 drivers/net/ppp/ppp_generic.c:731
1 lock held by syz.1.11304/6024:
#0: ffffffff8d5b0148 (ppp_mutex){+.+.}-{3:3}, at: ppp_ioctl+0xdc/0x1b20 drivers/net/ppp/ppp_generic.c:727
1 lock held by syz.1.11304/6025:
#0: ffffffff8dd5c4a8 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3f3/0x1ed0 drivers/net/tun.c:3107
1 lock held by syz.1.11304/6026:
#0: ffffffff8dd5c4a8 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3f3/0x1ed0 drivers/net/tun.c:3107
1 lock held by syz.3.11307/6033:
#0: ffffffff8dd5c4a8 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3f3/0x1ed0 drivers/net/tun.c:3107
1 lock held by syz.3.11307/6034:
#0: ffffffff8dd5c4a8 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3f3/0x1ed0 drivers/net/tun.c:3107
1 lock held by syz.3.11307/6035:
#0: ffffffff8dd5c4a8 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3f3/0x1ed0 drivers/net/tun.c:3107
=============================================
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 07/24/2026
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: 5790 Comm: syz.4.11228 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:release_pages+0x169/0x2340 mm/swap.c:978
Code: ff 45 31 ff 4c 39 64 24 78 0f 84 26 1f 00 00 e8 dd 20 d1 ff 49 83 c4 08 4d 89 fd 49 bf 00 00 00 00 00 fc ff df 48 8b 44 24 50 <4a> 8d 3c 20 48 89 f8 48 c1 e8 03 42 80 3c 38 00 74 05 e8 60 5a 22
RSP: 0018:ffffc900034d7200 EFLAGS: 00000012
RAX: ffffc900034d7428 RBX: ffffea0002462e48 RCX: ffff88807bdc5a00
RDX: 0000000000000000 RSI: ffffc900034d72a0 RDI: ffffea0002992588
RBP: ffffc900034d7328 R08: ffffea0002992587 R09: 1ffffd40005324b0
R10: dffffc0000000000 R11: fffff940005324b1 R12: 0000000000000020
R13: ffff8880798f0000 R14: ffffea0002992590 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055557b23c4e8 CR3: 0000000060881000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000200000000300
DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
__pagevec_release+0x6d/0xe0 mm/swap.c:1055
pagevec_release include/linux/pagevec.h:71 [inline]
folio_batch_release include/linux/pagevec.h:135 [inline]
shmem_undo_range+0x808/0x21d0 mm/shmem.c:946
shmem_truncate_range mm/shmem.c:1062 [inline]
shmem_evict_inode+0x225/0x9f0 mm/shmem.c:1171
evict+0x4b6/0x8b0 fs/inode.c:705
__dentry_kill+0x412/0x630 fs/dcache.c:611
dentry_kill+0xb8/0x290 fs/dcache.c:-1
dput+0xfa/0x1d0 fs/dcache.c:918
__fput+0x597/0x8b0 fs/file_table.c:328
task_work_run+0x1d0/0x260 kernel/task_work.c:203
exit_task_work include/linux/task_work.h:39 [inline]
do_exit+0x9d5/0x2570 kernel/exit.c:887
do_group_exit+0x229/0x2e0 kernel/exit.c:1030
get_signal+0x1259/0x1340 kernel/signal.c:2880
arch_do_signal_or_restart+0xc4/0x1310 arch/x86/kernel/signal.c:871
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316
exc_page_fault+0x88/0x100 arch/x86/mm/fault.c:1485
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0033:0x7fa0aa19e0e1
Code: Unable to access opcode bytes at 0x7fa0aa19e0b7.
RSP: 002b:fffffffffffffc70 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007fa0aa425fa0 RCX: 00007fa0aa19e0d9
RDX: 0000000000000000 RSI: fffffffffffffc70 RDI: 0000000001022000
RBP: 00007fa0aa235024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007fa0aa426038 R14: 00007fa0aa425fa0 R15: 00007fffdc4736d8