INFO: task kworker/1:3:4891 blocked for more than 143 seconds. Not tainted 5.11.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:3 state:D stack:28136 pid: 4891 ppid: 2 flags:0x00004000 Workqueue: ipv6_addrconf addrconf_verify_work Call Trace: context_switch kernel/sched/core.c:4327 [inline] __schedule+0x999/0xe70 kernel/sched/core.c:5078 schedule+0x14b/0x200 kernel/sched/core.c:5157 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:5216 __mutex_lock_common+0x124f/0x2f00 kernel/locking/mutex.c:1033 __mutex_lock kernel/locking/mutex.c:1103 [inline] mutex_lock_nested+0x1a/0x20 kernel/locking/mutex.c:1118 addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4570 process_one_work+0x789/0xfc0 kernel/workqueue.c:2275 worker_thread+0xac1/0x1300 kernel/workqueue.c:2421 kthread+0x39a/0x3c0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Showing all locks held in the system: 1 lock held by khungtaskd/1652: #0: ffffffff8c711680 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 arch/x86/pci/mmconfig_64.c:151 3 locks held by kworker/1:3/4891: #0: ffff88814775a138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x6f4/0xfc0 kernel/workqueue.c:2248 #1: ffffc90000e4fd78 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x733/0xfc0 kernel/workqueue.c:2250 #2: ffffffff8d6ee888 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4570 1 lock held by in:imklog/8107: #0: ffff88801d43a0f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x24e/0x2f0 fs/file.c:947 1 lock held by syz-executor716/8430: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1652 Comm: khungtaskd Not tainted 5.11.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x137/0x1be lib/dump_stack.c:120 nmi_cpu_backtrace+0x16c/0x190 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x191/0x2f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0xce9/0xd30 kernel/hung_task.c:294 kthread+0x39a/0x3c0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 8430 Comm: syz-executor716 Not tainted 5.11.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:mark_lock+0xd8/0x2030 kernel/locking/lockdep.c:4380 Code: 00 00 00 41 89 d4 49 89 fe 83 fa 08 75 28 48 8d 5e 20 48 89 d8 48 c1 e8 03 42 8a 04 28 84 c0 0f 85 66 11 00 00 8a 43 02 24 03 <3c> 01 41 bc 09 00 00 00 41 83 dc 00 41 bf 01 00 00 00 44 89 e1 41 RSP: 0018:ffffc900013eec10 EFLAGS: 00000046 RAX: 1ffff110031b7b00 RBX: ffff888018dbdd10 RCX: ffffffff815c27c9 RDX: 0000000000000008 RSI: ffff888018dbdcf0 RDI: ffff888018dbd340 RBP: ffffc900013eed30 R08: dffffc0000000000 R09: fffffbfff1f216aa R10: fffffbfff1f216aa R11: 0000000000000000 R12: 0000000000000008 R13: dffffc0000000000 R14: ffff888018dbd340 R15: ffff888018dbdd10 FS: 000000000118d300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fff7a08d8d8 CR3: 0000000022fea000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: mark_usage kernel/locking/lockdep.c:4332 [inline] __lock_acquire+0xccf/0x5e90 kernel/locking/lockdep.c:4786 lock_acquire+0x114/0x5e0 kernel/locking/lockdep.c:5442 __mutex_lock_common+0x173/0x2f00 kernel/locking/mutex.c:956 __mutex_lock kernel/locking/mutex.c:1103 [inline] mutex_lock_nested+0x1a/0x20 kernel/locking/mutex.c:1118 tcf_idr_check_alloc+0xa4/0x380 net/sched/act_api.c:549 tcf_police_init+0x1ce/0x1580 net/sched/act_police.c:81 tcf_action_init_1+0x40d/0xa80 net/sched/act_api.c:1013 tcf_exts_validate+0xd6/0x370 net/sched/cls_api.c:3046 basic_set_parms net/sched/cls_basic.c:153 [inline] basic_change+0x556/0x12d0 net/sched/cls_basic.c:219 tc_new_tfilter+0x13ea/0x2d60 net/sched/cls_api.c:2127 rtnetlink_rcv_msg+0x8f9/0xd60 net/core/rtnetlink.c:5544 netlink_rcv_skb+0x190/0x3a0 net/netlink/af_netlink.c:2494 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline] netlink_unicast+0x786/0x940 net/netlink/af_netlink.c:1330 netlink_sendmsg+0x9ae/0xd50 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg net/socket.c:672 [inline] ____sys_sendmsg+0x519/0x800 net/socket.c:2345 ___sys_sendmsg net/socket.c:2399 [inline] __sys_sendmmsg+0x453/0x680 net/socket.c:2489 __do_sys_sendmmsg net/socket.c:2518 [inline] __se_sys_sendmmsg net/socket.c:2515 [inline] __x64_sys_sendmmsg+0x9c/0xb0 net/socket.c:2515 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x440229 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 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 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff7a08d8f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000440229 RDX: 010efe10675dec16 RSI: 0000000020000200 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00000000004ab000 R09: 00000000004ab000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000008f669 R13: 00007fff7a08d920 R14: 00007fff7a08d910 R15: 00007fff7a08d904