INFO: task kworker/1:0:8486 blocked for more than 143 seconds. Not tainted 5.11.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:0 state:D stack:29624 pid: 8486 ppid: 2 flags:0x00004000 Workqueue: ipv6_addrconf addrconf_verify_work Call Trace: context_switch kernel/sched/core.c:4313 [inline] __schedule+0x90c/0x21a0 kernel/sched/core.c:5064 schedule+0xcf/0x270 kernel/sched/core.c:5143 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:5202 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x81a/0x1110 kernel/locking/mutex.c:1103 addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4569 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x3b1/0x4a0 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/1659: #0: ffffffff8b373920 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6254 1 lock held by in:imklog/8167: #0: ffff888018bbe370 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:947 3 locks held by kworker/1:0/8486: #0: ffff8881478e2538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881478e2538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff8881478e2538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff8881478e2538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff8881478e2538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff8881478e2538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x871/0x15f0 kernel/workqueue.c:2246 #1: ffffc90001d9fda8 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x8a5/0x15f0 kernel/workqueue.c:2250 #2: ffffffff8ca586a8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4569 2 locks held by syz-executor330/8517: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1659 Comm: khungtaskd Not tainted 5.11.0-rc3-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+0x107/0x163 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 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+0xd43/0xfa0 kernel/hung_task.c:294 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 8517 Comm: syz-executor330 Not tainted 5.11.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:rcu_lockdep_current_cpu_online kernel/rcu/tree.c:1162 [inline] RIP: 0010:rcu_lockdep_current_cpu_online+0x83/0x150 kernel/rcu/tree.c:1152 Code: 3c 02 00 0f 85 ad 00 00 00 48 03 1c ed c0 c6 e6 8a 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 18 48 89 fa 48 c1 ea 03 80 3c 02 00 <0f> 85 90 00 00 00 48 8d 7b 20 48 8b 6b 18 48 b8 00 00 00 00 00 fc RSP: 0018:ffffc900019aeb98 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ffff8880b9f35a80 RCX: ffffffff8158c5c1 RDX: 1ffff110173e6b53 RSI: 0000000000000002 RDI: ffff8880b9f35a98 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff8d03798f R10: fffffbfff1a06f31 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000001 R14: 1ffff92000335d95 R15: ffff888014509600 FS: 0000000002517880(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fada5059000 CR3: 0000000020898000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock_held_common kernel/rcu/update.c:110 [inline] rcu_read_lock_held_common kernel/rcu/update.c:100 [inline] rcu_read_lock_sched_held+0x25/0x70 kernel/rcu/update.c:121 trace_lock_release include/trace/events/lock.h:58 [inline] lock_release+0x5b7/0x710 kernel/locking/lockdep.c:5448 __mutex_unlock_slowpath+0x81/0x610 kernel/locking/mutex.c:1228 tcf_idr_check_alloc+0x29e/0x3b0 net/sched/act_api.c:556 tcf_police_init+0x34f/0x1460 net/sched/act_police.c:81 tcf_action_init_1+0x1a3/0x990 net/sched/act_api.c:1013 tcf_exts_validate+0x138/0x420 net/sched/cls_api.c:3046 fw_set_parms+0x13d/0xaa0 net/sched/cls_fw.c:208 fw_change+0xa30/0x13e0 net/sched/cls_fw.c:329 tc_new_tfilter+0x1394/0x2120 net/sched/cls_api.c:2127 rtnetlink_rcv_msg+0x80e/0xad0 net/core/rtnetlink.c:5544 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:672 ____sys_sendmsg+0x331/0x810 net/socket.c:2345 ___sys_sendmsg+0xf3/0x170 net/socket.c:2399 __sys_sendmmsg+0x195/0x470 net/socket.c:2489 __do_sys_sendmmsg net/socket.c:2518 [inline] __se_sys_sendmmsg net/socket.c:2515 [inline] __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2515 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x441739 Code: e8 5c ad 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 0f 83 bb 09 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffc1c73d538 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000441739 RDX: 010efe10675dec16 RSI: 0000000020000200 RDI: 0000000000000003 RBP: 00007ffc1c73d540 R08: 0000000100000000 R09: 0000000100000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000773a5 R13: 0000000000402610 R14: 0000000000000000 R15: 0000000000000000 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.774 msecs