syzbot

INFO: task kworker/1:2:1067 blocked for more than 143 seconds.
      Not tainted 5.15.161-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:2     state:D stack:26688 pid: 1067 ppid:     2 flags:0x00004000
Workqueue: ipv6_addrconf addrconf_verify_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1f0 kernel/sched/core.c:6459
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6518
 __mutex_lock_common+0xe34/0x25a0 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4656
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c91fae0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
3 locks held by kworker/1:2/1067:
 #0: ffff888023916138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc900046cfd20 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffffffff8d9e8348 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4656
2 locks held by getty/3256:
 #0: ffff8880248ce098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc9000249b2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158
1 lock held by syz-executor108/3522:

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.15.161-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xe72/0xeb0 kernel/hung_task.c:295
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3522 Comm: syz-executor108 Not tainted 5.15.161-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
RIP: 0010:___might_sleep+0x1cf/0x6a0 kernel/sched/core.c:9594
Code: 00 00 00 00 00 9c 8f 84 24 a0 00 00 00 42 80 3c 33 00 74 0e 4c 89 e7 48 89 d3 e8 ec 00 71 00 48 89 da f6 84 24 a1 00 00 00 02 <45> 89 ec 74 46 4c 8d 62 2c 4c 89 e0 48 c1 e8 03 42 0f b6 04 30 84
RSP: 0018:ffffc90002f365a0 EFLAGS: 00000202
RAX: 0000000000000000 RBX: 1ffff920005e6cc8 RCX: ffff8880135f5940
RDX: ffff8880135f5940 RSI: ffffffff8a8b3ca0 RDI: ffffffff8ad8f740
RBP: ffffc90002f366b0 R08: dffffc0000000000 R09: ffffc90002f36780
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffc90002f36640
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff920005e6cbc
FS:  00005555573bb380(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005586a0a4c6d8 CR3: 000000001c11c000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 __mutex_lock_common+0xd4/0x25a0 kernel/locking/mutex.c:573
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 tcf_idr_check_alloc+0xa1/0x380 net/sched/act_api.c:568
 tcf_police_init+0x294/0x17c0 net/sched/act_police.c:84
 tcf_action_init_1+0x50f/0x7f0 net/sched/act_api.c:1051
 tcf_action_init+0x2f3/0x750 net/sched/act_api.c:1110
 tcf_action_add net/sched/act_api.c:1522 [inline]
 tc_ctl_action+0x49b/0xd00 net/sched/act_api.c:1581
 rtnetlink_rcv_msg+0x993/0xee0 net/core/rtnetlink.c:5629
 netlink_rcv_skb+0x1cf/0x410 net/netlink/af_netlink.c:2508
 netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
 netlink_unicast+0x7b6/0x980 net/netlink/af_netlink.c:1356
 netlink_sendmsg+0xa30/0xd60 net/netlink/af_netlink.c:1924
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2431
 ___sys_sendmsg+0x252/0x2e0 net/socket.c:2485
 __sys_sendmsg net/socket.c:2514 [inline]
 __do_sys_sendmsg net/socket.c:2523 [inline]
 __se_sys_sendmsg+0x19a/0x260 net/socket.c:2521
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f9d0183bdf9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffeb0daa0d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f9d0183bdf9
RDX: 0000000000000000 RSI: 0000000020000300 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000006
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 2.174 msecs