INFO: task kworker/u8:6:1095 blocked for more than 143 seconds. Not tainted 6.10.0-rc2-syzkaller-00761-g3ec8d7572a69 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:6 state:D stack:21816 pid:1095 tgid:1095 ppid:2 flags:0x00004000 Workqueue: ipv6_addrconf addrconf_verify_work Call Trace: context_switch kernel/sched/core.c:5408 [inline] __schedule+0x17e8/0x4a20 kernel/sched/core.c:6745 __schedule_loop kernel/sched/core.c:6822 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6837 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6894 __mutex_lock_common kernel/locking/mutex.c:684 [inline] __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752 addrconf_verify_work+0x19/0x30 net/ipv6/addrconf.c:4733 process_one_work kernel/workqueue.c:3231 [inline] process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312 worker_thread+0x86d/0xd70 kernel/workqueue.c:3393 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #0: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #0: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6614 3 locks held by kworker/u8:6/1095: #0: ffff8880298cf948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3206 [inline] #0: ffff8880298cf948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312 #1: ffffc90004687d00 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3207 [inline] #1: ffffc90004687d00 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312 #2: ffffffff8f5e7648 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0x19/0x30 net/ipv6/addrconf.c:4733 2 locks held by getty/4844: #0: ffff88802a6a60a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002f062f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b5/0x1e10 drivers/tty/n_tty.c:2201 1 lock held by syz-executor230/5108: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 30 Comm: khungtaskd Not tainted 6.10.0-rc2-syzkaller-00761-g3ec8d7572a69 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline] watchdog+0xfde/0x1020 kernel/hung_task.c:379 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5108 Comm: syz-executor230 Not tainted 6.10.0-rc2-syzkaller-00761-g3ec8d7572a69 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 RIP: 0010:rcu_preempt_read_exit kernel/rcu/tree_plugin.h:384 [inline] RIP: 0010:__rcu_read_unlock+0x38/0x110 kernel/rcu/tree_plugin.h:423 Code: 49 bc 00 00 00 00 00 fc ff df 65 4c 8b 34 25 00 d5 03 00 4d 8d ae 44 04 00 00 4c 89 eb 48 c1 eb 03 42 0f b6 04 23 84 c0 75 6b <41> 8b 6d 00 ff cd 42 0f b6 04 23 84 c0 75 76 41 89 6d 00 85 ed 75 RSP: 0018:ffffc9000354e6c8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 1ffff110045d5bc8 RCX: ffffc9000354e603 RDX: 0000000000000001 RSI: ffffffff8bcacd00 RDI: ffffffff8c1ff680 RBP: ffffc9000354e7d0 R08: ffffffff8fad9aaf R09: 1ffffffff1f5b355 R10: dffffc0000000000 R11: fffffbfff1f5b356 R12: dffffc0000000000 R13: ffff888022eade44 R14: ffff888022eada00 R15: dffffc0000000000 FS: 00005555822df380(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000563883f10600 CR3: 0000000022282000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_unlock include/linux/rcupdate.h:814 [inline] tcf_idr_check_alloc+0x104/0x900 net/sched/act_api.c:841 tcf_police_init+0x29b/0x17c0 net/sched/act_police.c:75 tcf_action_init_1+0x5d7/0x890 net/sched/act_api.c:1426 tcf_action_init+0x2e4/0x940 net/sched/act_api.c:1489 tcf_action_add net/sched/act_api.c:2062 [inline] tc_ctl_action+0x47d/0xcf0 net/sched/act_api.c:2119 rtnetlink_rcv_msg+0x89b/0x1180 net/core/rtnetlink.c:6641 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline] netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1357 netlink_sendmsg+0x8db/0xcb0 net/netlink/af_netlink.c:1901 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2585 ___sys_sendmsg net/socket.c:2639 [inline] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2668 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1f58561df9 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:00007fff16d84d48 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f1f58561df9 RDX: 0000000000000000 RSI: 0000000020000300 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000006 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.947 msecs