INFO: task kworker/0:1:8489 blocked for more than 143 seconds. Not tainted 5.11.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:1 state:D stack:29448 pid: 8489 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:4570 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/1654: #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/8225: #0: ffff8880181ce870 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:947 3 locks held by kworker/0:1/8489: #0: ffff888146f31538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888146f31538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff888146f31538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff888146f31538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff888146f31538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888146f31538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x871/0x15f0 kernel/workqueue.c:2246 #1: ffffc90000fafda8 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x8a5/0x15f0 kernel/workqueue.c:2250 #2: ffffffff8ca58da8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4570 2 locks held by syz-executor986/8519: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1654 Comm: khungtaskd Not tainted 5.11.0-rc4-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: 8519 Comm: syz-executor986 Not tainted 5.11.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:find_held_lock+0xbc/0x110 kernel/locking/lockdep.c:4956 Code: 0f b6 5b 21 48 89 f8 48 89 fa 48 c1 e8 03 83 e2 07 0f b6 04 28 38 d0 7f 04 84 c0 75 4e 41 32 5c 24 21 83 e3 60 74 94 45 31 e4 <48> b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 0f b6 14 02 4c RSP: 0018:ffffc9000160ebf8 EFLAGS: 00000002 RAX: 0000000000000001 RBX: 0000000000000002 RCX: ffffc9000160ec80 RDX: 0000000000000002 RSI: ffff8880113c7c68 RDI: ffff88801f932570 RBP: 1ffff920002c1d88 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff88801f932570 R13: ffff8880113c7c68 R14: ffffc9000160ec80 R15: 0000000000000001 FS: 0000000001ef7880(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f00aca2d000 CR3: 0000000011a8d000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lock_release kernel/locking/lockdep.c:5119 [inline] lock_release+0x1f2/0x710 kernel/locking/lockdep.c:5457 __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 cls_bpf_set_parms net/sched/cls_bpf.c:422 [inline] cls_bpf_change+0x60b/0x1b80 net/sched/cls_bpf.c:506 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: 0033:0x441759 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:00007ffea6f84a18 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000441759 RDX: 010efe10675dec16 RSI: 0000000020000200 RDI: 0000000000000003 RBP: 00007ffea6f84a20 R08: 0000000100000000 R09: 0000000100000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000007a8eb R13: 0000000000402630 R14: 0000000000000000 R15: 0000000000000000 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.700 msecs