syzbot


INFO: task hung in return_address

Status: upstream: reported on 2025/05/23 23:20
Reported-by: syzbot+1eb0f920273f35ed10b3@syzkaller.appspotmail.com
First crash: 10d, last: 10d

Sample crash report:
INFO: task dhcpcd:3968 blocked for more than 145 seconds.
      Not tainted 6.1.140-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:dhcpcd          state:R  running task     stack:0     pid:3968  ppid:3967   flags:0x0000000c
Call trace:
 __switch_to+0x2f4/0x568 arch/arm64/kernel/process.c:555
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0xdd4/0x1b2c kernel/sched/core.c:6561
 preempt_schedule_common+0xec/0x1a0 kernel/sched/core.c:6730
 return_address+0x94/0x104 arch/arm64/kernel/return_address.c:42
 0x0

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffff8000152476b0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xbb4 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffff800015247ed0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xbb4 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffff800015246d40 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:349
2 locks held by kworker/u4:2/39:
 #0: ffff0000c0029138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
 #1: ffff80001cd37c20 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
2 locks held by dhcpcd/3968:
2 locks held by getty/4071:
 #0: ffff0000d025f098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80001ce602f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x2ec/0xf9c drivers/tty/n_tty.c:2198
1 lock held by syz-executor/4286:
2 locks held by kworker/1:3/4343:
 #0: ffff0000c0021938 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
 #1: ffff800020937c20 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
2 locks held by kworker/u4:6/4356:
 #0: ffff0000c0029138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
 #1: ffff800020c07c20 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
4 locks held by kworker/u4:12/4511:
 #0: ffff0000c03dd138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
 #1: ffff8000210b7c20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
 #2: ffff8000176ccb90 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x12c/0xa74 net/core/net_namespace.c:594
 #3: ffff0000da43d3e8 (&wg->device_update_lock){+.+.}-{3:3}, at: wg_destruct+0x114/0x2d4 drivers/net/wireguard/device.c:249
2 locks held by kworker/u4:25/6816:
1 lock held by syz-executor/11920:
1 lock held by syz-executor/12298:
 #0: ffff80001524c9f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
 #0: ffff80001524c9f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x264/0x6f0 kernel/rcu/tree_exp.h:962
1 lock held by syz-executor/12328:
1 lock held by syz-executor/12587:
3 locks held by syz-executor/12589:
1 lock held by syz-executor/12600:
1 lock held by syz-executor/12607:
1 lock held by syz.4.2098/12900:
 #0: ffff0000e24f4a10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #0: ffff0000e24f4a10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:653 [inline]
 #0: ffff0000e24f4a10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x7c/0x1f8 net/socket.c:1400
1 lock held by dhcpcd/12907:
 #0: ffff0000dc440130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1756 [inline]
 #0: ffff0000dc440130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x48/0xb2c net/packet/af_packet.c:3249
1 lock held by dhcpcd/12908:
 #0: ffff0000cc59e130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1756 [inline]
 #0: ffff0000cc59e130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x48/0xb2c net/packet/af_packet.c:3249
1 lock held by dhcpcd/12912:
 #0: ffff0000dc446130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1756 [inline]
 #0: ffff0000dc446130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x48/0xb2c net/packet/af_packet.c:3249
1 lock held by dhcpcd/12913:
 #0: ffff0000f71e6130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1756 [inline]
 #0: ffff0000f71e6130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x48/0xb2c net/packet/af_packet.c:3249
1 lock held by dhcpcd/12914:
 #0: ffff0001066b8130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1756 [inline]
 #0: ffff0001066b8130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x48/0xb2c net/packet/af_packet.c:3249
1 lock held by dhcpcd/12915:
 #0: ffff0000cb3cc130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1756 [inline]
 #0: ffff0000cb3cc130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x48/0xb2c net/packet/af_packet.c:3249
1 lock held by dhcpcd/12918:
 #0: ffff0000f4c90130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1756 [inline]
 #0: ffff0000f4c90130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x48/0xb2c net/packet/af_packet.c:3249
1 lock held by dhcpcd/12919:
 #0: ffff0000d5832130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1756 [inline]
 #0: ffff0000d5832130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x48/0xb2c net/packet/af_packet.c:3249
1 lock held by dhcpcd/12920:
 #0: ffff000106ec0130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1756 [inline]
 #0: ffff000106ec0130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x48/0xb2c net/packet/af_packet.c:3249
1 lock held by dhcpcd/12921:
 #0: ffff0000d0014130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1756 [inline]
 #0: ffff0000d0014130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x48/0xb2c net/packet/af_packet.c:3249
2 locks held by dhcpcd-run-hook/12923:

=============================================


Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/23 23:19 linux-6.1.y da3c5173c55f f8cc0c83 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in return_address
* Struck through repros no longer work on HEAD.