INFO: task kworker/0:1:6862 blocked for more than 143 seconds. Not tainted 5.9.0-rc8-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:1 state:D stack:29856 pid: 6862 ppid: 2 flags:0x00004000 Workqueue: ipv6_addrconf addrconf_verify_work Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0xec9/0x2280 kernel/sched/core.c:4527 schedule+0xd0/0x2a0 kernel/sched/core.c:4602 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x3e2/0x10e0 kernel/locking/mutex.c:1103 addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4568 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Showing all locks held in the system: 1 lock held by khungtaskd/1133: #0: ffffffff8a068480 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5852 1 lock held by in:imklog/6616: #0: ffff8880a74e9b70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:930 3 locks held by kworker/0:1/6862: #0: ffff888099c9d138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888099c9d138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff888099c9d138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff888099c9d138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff888099c9d138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888099c9d138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240 #1: ffffc900054d7da8 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 #2: ffffffff8b17bd08 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4568 1 lock held by syz-executor833/6893: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1133 Comm: khungtaskd Not tainted 5.9.0-rc8-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x198/0x1fd lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x223 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+0xd7d/0x1000 kernel/hung_task.c:295 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 6893 Comm: syz-executor833 Not tainted 5.9.0-rc8-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__mutex_lock_common kernel/locking/mutex.c:956 [inline] RIP: 0010:__mutex_lock+0x11c/0x10e0 kernel/locking/mutex.c:1103 Code: 3c 02 00 0f 85 fb 0e 00 00 48 3b 6d 60 0f 85 72 09 00 00 bf 01 00 00 00 e8 c1 dc 17 f9 48 8d 45 68 31 d2 31 c9 48 89 44 24 40 <48> 89 c7 49 89 d9 44 89 e6 ff 74 24 20 41 b8 01 00 00 00 e8 6c dd RSP: 0018:ffffc90005376c90 EFLAGS: 00000246 RAX: ffff88809d968268 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8a0683c0 RDI: ffff888092c67380 RBP: ffff88809d968200 R08: ffffffff86981fb8 R09: ffff88809d968207 R10: ffffed1013b2d040 R11: 0000000000000000 R12: 0000000000000000 R13: dffffc0000000000 R14: ffff88809d968200 R15: ffff88809d968290 FS: 0000000001bd5880(0000) GS:ffff8880ae500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f53746be000 CR3: 000000009de21000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: tcf_idr_check_alloc+0x78/0x3b0 net/sched/act_api.c:501 tcf_police_init+0x347/0x13a0 net/sched/act_police.c:81 tcf_action_init_1+0x1a3/0x990 net/sched/act_api.c:993 tcf_exts_validate+0x138/0x420 net/sched/cls_api.c:3058 route4_set_parms net/sched/cls_route.c:393 [inline] route4_change+0x6d8/0x2380 net/sched/cls_route.c:512 tc_new_tfilter+0x1398/0x2130 net/sched/cls_api.c:2129 rtnetlink_rcv_msg+0x80f/0xad0 net/core/rtnetlink.c:5554 netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2489 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:651 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:671 ____sys_sendmsg+0x331/0x810 net/socket.c:2353 ___sys_sendmsg+0xf3/0x170 net/socket.c:2407 __sys_sendmmsg+0x195/0x480 net/socket.c:2497 __do_sys_sendmmsg net/socket.c:2526 [inline] __se_sys_sendmmsg net/socket.c:2523 [inline] __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2523 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x441599 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:00007ffc72b39eb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000441599 RDX: 04924924924926d3 RSI: 0000000020000200 RDI: 0000000000000004 RBP: 00007ffc72b39ec0 R08: 0000000100000000 R09: 0000000100000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000007c727 R13: 0000000000402470 R14: 0000000000000000 R15: 0000000000000000 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 0.000 msecs