INFO: task kworker/0:4:25082 blocked for more than 140 seconds. Not tainted 4.14.179-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:4 D30080 25082 2 0x80000000 Workqueue: ipv6_addrconf addrconf_verify_work Call Trace: schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893 addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4412 process_one_work+0x813/0x1540 kernel/workqueue.c:2116 worker_thread+0x5d1/0x1070 kernel/workqueue.c:2250 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 INFO: task kworker/1:5:27328 blocked for more than 140 seconds. Not tainted 4.14.179-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:5 D29432 27328 2 0x80000000 Workqueue: events switchdev_deferred_process_work Call Trace: schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893 switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:150 process_one_work+0x813/0x1540 kernel/workqueue.c:2116 worker_thread+0x5d1/0x1070 kernel/workqueue.c:2250 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Showing all locks held in the system: 1 lock held by khungtaskd/1055: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 2 locks held by agetty/6059: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156 5 locks held by kworker/u4:0/21370: #0: ("%s""netns"){+.+.}, at: [] work_static include/linux/workqueue.h:199 [inline] #0: ("%s""netns"){+.+.}, at: [] set_work_data kernel/workqueue.c:619 [inline] #0: ("%s""netns"){+.+.}, at: [] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ("%s""netns"){+.+.}, at: [] process_one_work+0x727/0x1540 kernel/workqueue.c:2087 #1: (net_cleanup_work){+.+.}, at: [] process_one_work+0x761/0x1540 kernel/workqueue.c:2091 #2: (net_mutex){+.+.}, at: [] cleanup_net+0x123/0x820 net/core/net_namespace.c:450 #3: (ovs_mutex){+.+.}, at: [] ovs_lock net/openvswitch/datapath.c:117 [inline] #3: (ovs_mutex){+.+.}, at: [] ovs_exit_net+0x19a/0xa40 net/openvswitch/datapath.c:2372 #4: (rtnl_mutex){+.+.}, at: [] ovs_exit_net+0x23e/0xa40 net/openvswitch/datapath.c:2376 3 locks held by kworker/0:4/25082: #0: ("%s"("ipv6_addrconf")){+.+.}, at: [] work_static include/linux/workqueue.h:199 [inline] #0: ("%s"("ipv6_addrconf")){+.+.}, at: [] set_work_data kernel/workqueue.c:619 [inline] #0: ("%s"("ipv6_addrconf")){+.+.}, at: [] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ("%s"("ipv6_addrconf")){+.+.}, at: [] process_one_work+0x727/0x1540 kernel/workqueue.c:2087 #1: ((addr_chk_work).work){+.+.}, at: [] process_one_work+0x761/0x1540 kernel/workqueue.c:2091 #2: (rtnl_mutex){+.+.}, at: [] addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4412 1 lock held by syz-executor.4/25194: #0: (rtnl_mutex){+.+.}, at: [] netdev_run_todo+0x1e6/0x710 net/core/dev.c:7920 3 locks held by kworker/1:5/27328: #0: ("events"){+.+.}, at: [] work_static include/linux/workqueue.h:199 [inline] #0: ("events"){+.+.}, at: [] set_work_data kernel/workqueue.c:619 [inline] #0: ("events"){+.+.}, at: [] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ("events"){+.+.}, at: [] process_one_work+0x727/0x1540 kernel/workqueue.c:2087 #1: (deferred_process_work){+.+.}, at: [] process_one_work+0x761/0x1540 kernel/workqueue.c:2091 #2: (rtnl_mutex){+.+.}, at: [] switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:150 1 lock held by syz-executor.3/27375: #0: (rtnl_mutex){+.+.}, at: [] netdev_run_todo+0x1e6/0x710 net/core/dev.c:7920 3 locks held by kworker/0:5/27659: #0: ("events"){+.+.}, at: [] work_static include/linux/workqueue.h:199 [inline] #0: ("events"){+.+.}, at: [] set_work_data kernel/workqueue.c:619 [inline] #0: ("events"){+.+.}, at: [] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ("events"){+.+.}, at: [] process_one_work+0x727/0x1540 kernel/workqueue.c:2087 #1: ((linkwatch_work).work){+.+.}, at: [] process_one_work+0x761/0x1540 kernel/workqueue.c:2091 #2: (rtnl_mutex){+.+.}, at: [] linkwatch_event+0xa/0x50 net/core/link_watch.c:236 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1055 Comm: khungtaskd Not tainted 4.14.179-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x13e/0x194 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x139/0x17e lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x5e2/0xb80 kernel/hung_task.c:274 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 21119 Comm: syz-executor.5 Not tainted 4.14.179-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff88809552e600 task.stack: ffff88820af18000 RIP: 0010:memcmp+0x3e/0xb0 lib/string.c:861 RSP: 0000:ffff88820af1f8e8 EFLAGS: 00000002 RAX: 0000000000000000 RBX: ffff88820af1f984 RCX: 0000000000000003 RDX: 0000000000000004 RSI: ffff88806885c5ac RDI: ffff88820af1f980 RBP: dffffc0000000000 R08: 0000000000000001 R09: 0000000000000001 R10: ffff88809552eeb0 R11: ffff88809552e600 R12: ffff88820af1f9d0 R13: 000000000000000a R14: ffff88820af1f980 R15: ffff88806885c590 FS: 00007ff575852700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000006b429000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: find_stack lib/stackdepot.c:180 [inline] depot_save_stack+0x10d/0x401 lib/stackdepot.c:229 save_stack+0x89/0xa0 mm/kasan/kasan.c:453 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc mm/kasan/kasan.c:551 [inline] kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:529 slab_post_alloc_hook mm/slab.h:442 [inline] slab_alloc mm/slab.c:3390 [inline] kmem_cache_alloc+0x114/0x770 mm/slab.c:3550 __sigqueue_alloc+0x1b8/0x3e0 kernel/signal.c:400 __send_signal+0x194/0x1280 kernel/signal.c:1097 specific_send_sig_info kernel/signal.c:1208 [inline] force_sig_info+0x240/0x340 kernel/signal.c:1260 force_sig_info_fault.constprop.0+0x185/0x260 arch/x86/mm/fault.c:225 __bad_area_nosemaphore+0x1d9/0x2a0 arch/x86/mm/fault.c:940 __do_page_fault+0x859/0xb40 arch/x86/mm/fault.c:1412 page_fault+0x45/0x50 arch/x86/entry/entry_64.S:1122 RIP: 0c29:0x4c1955 RSP: 509620:000000000078bf00 EFLAGS: ffffffff Code: fc ff df 53 48 89 fb 48 83 ec 10 eb 0d 48 83 c3 01 48 83 c6 01 49 39 dc 74 45 48 89 d8 48 89 da 48 c1 e8 03 83 e2 07 0f b6 04 28 <38> d0 7f 04 84 c0 75 54 48 89 f2 48 89 f1 0f b6 03 48 c1 ea 03