INFO: task syz.2.1921:14926 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.1921 state:D stack:25960 pid:14926 tgid:14922 ppid:5833 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
__mutex_lock_common kernel/locking/mutex.c:676 [inline]
__mutex_lock+0x818/0x1060 kernel/locking/mutex.c:760
fdget_pos+0x2a2/0x370 fs/file.c:1232
class_fd_pos_constructor include/linux/file.h:85 [inline]
ksys_write+0x71/0x250 fs/read_write.c:729
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0309b8eec9
RSP: 002b:00007f030a9d1038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f0309de5fa0 RCX: 00007f0309b8eec9
RDX: 0000000000000800 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007f0309c11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0309de6038 R14: 00007f0309de5fa0 R15: 00007ffdb2cfec48
Showing all locks held in the system:
4 locks held by kworker/u8:1/13:
#0: ffff88801ba9f148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
#1: ffffc90000127d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
#2: ffffffff900e8630 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xad/0x8b0 net/core/net_namespace.c:669
#3: ffffffff8e3cf878 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343
1 lock held by khungtaskd/31:
#0: ffffffff8e3c42e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e3c42e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e3c42e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
1 lock held by klogd/5190:
3 locks held by kworker/0:6/5923:
#0: ffff8880b843a4d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:638
#1: ffff8880b8424088 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:220 [inline]
#1: ffff8880b8424088 (psi_seq){-.-.}-{0:0}, at: __schedule+0x1861/0x5de0 kernel/sched/core.c:6923
#2: ffffffff8eee0fb8 (pool_lock#2){-.-.}-{2:2}, at: class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:557 [inline]
#2: ffffffff8eee0fb8 (pool_lock#2){-.-.}-{2:2}, at: free_obj_work+0x1be/0x3d0 lib/debugobjects.c:498
1 lock held by syz.0.1539/13090:
1 lock held by syz.0.1539/13091:
1 lock held by syz.2.1921/14926:
#0: ffff88806ab917b8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2a2/0x370 fs/file.c:1232
2 locks held by syz.2.1921/14927:
2 locks held by getty/15340:
#0: ffff88803446d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc90002e562f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
8 locks held by syz.6.2241/16631:
#0: ffff88807555e638 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2a2/0x370 fs/file.c:1232
#1: ffff888023e64420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738
#2: ffff88805b204c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x570 fs/kernfs/file.c:343
#3: ffff88801def8c38 (kn->active#251){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#3: ffff88801def8c38 (kn->active#251){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2ff/0x570 fs/kernfs/file.c:344
#4: ffffffff8f288788 (device_hotplug_lock){+.+.}-{4:4}, at: lock_device_hotplug_sysfs drivers/base/core.c:2355 [inline]
#4: ffffffff8f288788 (device_hotplug_lock){+.+.}-{4:4}, at: online_store+0x9a/0x180 drivers/base/core.c:2805
#5: ffff8880b8536d50 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#5: ffff8880b8536d50 (&dev->mutex){....}-{4:4}, at: device_online+0x27/0x1c0 drivers/base/core.c:4222
#6: ffffffff8e265370 (cpu_hotplug_lock){++++}-{0:0}, at: mem_hotplug_begin mm/memory_hotplug.c:261 [inline]
#6: ffffffff8e265370 (cpu_hotplug_lock){++++}-{0:0}, at: try_online_node+0x11/0x50 mm/memory_hotplug.c:1328
#7: ffffffff8e56d590 (mem_hotplug_lock){++++}-{0:0}, at: mem_hotplug_begin mm/memory_hotplug.c:262 [inline]
#7: ffffffff8e56d590 (mem_hotplug_lock){++++}-{0:0}, at: try_online_node+0x1d/0x50 mm/memory_hotplug.c:1328
1 lock held by dhcpcd/16630:
#0: ffff88803173e258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1679 [inline]
#0: ffff88803173e258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3197
1 lock held by dhcpcd/16633:
#0: ffff88802f40e258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1679 [inline]
#0: ffff88802f40e258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3197
1 lock held by dhcpcd/16634:
#0: ffff88803c4d4258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1679 [inline]
#0: ffff88803c4d4258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3197
1 lock held by dhcpcd/16635:
#0: ffff888042050258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1679 [inline]
#0: ffff888042050258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3197
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
watchdog+0xf3f/0x1170 kernel/hung_task.c:495
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245