INFO: task kworker/1:6:2799 blocked for more than 143 seconds. Not tainted 5.6.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:6 D26208 2799 2 0x80004000 Workqueue: ipv6_addrconf addrconf_verify_work Call Trace: schedule+0xd0/0x2a0 kernel/sched/core.c:4168 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4227 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4584 process_one_work+0x965/0x16a0 kernel/workqueue.c:2266 worker_thread+0x96/0xe20 kernel/workqueue.c:2412 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Showing all locks held in the system: 1 lock held by khungtaskd/1138: #0: ffffffff899bc180 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5743 3 locks held by khugepaged/1146: 3 locks held by kworker/1:6/2799: #0: ffff8880a9387d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8880a9387d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880a9387d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8880a9387d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8880a9387d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8880a9387d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8880a9387d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x844/0x16a0 kernel/workqueue.c:2237 #1: ffffc90007d6fdc0 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x878/0x16a0 kernel/workqueue.c:2241 #2: ffffffff8a578468 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4584 3 locks held by kworker/0:4/3464: #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x844/0x16a0 kernel/workqueue.c:2237 #1: ffffc9000b2bfdc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x878/0x16a0 kernel/workqueue.c:2241 #2: ffffffff8a578468 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xb/0x60 net/core/link_watch.c:242 1 lock held by systemd-journal/4105: 1 lock held by in:imklog/6718: #0: ffff8880a84a25f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 4 locks held by kworker/u4:2/11947: 1 lock held by syz-executor.1/16845: 1 lock held by syz-executor.1/16954: 1 lock held by syz-executor.1/17534: 1 lock held by syz-executor.1/17642: 1 lock held by syz-executor.0/17792: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1138 Comm: khungtaskd Not tainted 5.6.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x231/0x27e lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xa8c/0x1010 kernel/hung_task.c:289 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 17381 Comm: syz-executor.1 Not tainted 5.6.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__sanitizer_cov_trace_pc+0x47/0x50 kernel/kcov.c:197 Code: 90 d8 13 00 00 83 fa 02 75 20 48 8b 88 e0 13 00 00 8b 80 dc 13 00 00 48 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 0f 1f 84 00 00 00 00 00 65 4c 8b 04 25 00 1f 02 00 65 8b 05 38 RSP: 0000:ffffc90016897d20 EFLAGS: 00000293 RAX: ffff8880a0e041c0 RBX: 0000000000000000 RCX: ffffffff812a06cd RDX: 0000000000000000 RSI: ffffffff8129e43a RDI: 0000000000000001 RBP: ffff8880a0e041c0 R08: ffff8880a0e041c0 R09: fffffbfff1511e99 R10: ffffffff8a88f4c7 R11: fffffbfff1511e98 R12: ffff8880a0e041c0 R13: ffffc90016897f58 R14: ffffc90016897ff0 R15: 00007fbff76de4b8 FS: 00007fbff76df700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000021d76068 CR3: 00000000929df000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: get_current arch/x86/include/asm/current.h:15 [inline] fpregs_mark_activate+0x1a/0x320 arch/x86/kernel/fpu/core.c:367 copy_init_fpstate_to_fpregs arch/x86/kernel/fpu/core.c:311 [inline] fpu__clear+0x17f/0x430 arch/x86/kernel/fpu/core.c:332 handle_signal arch/x86/kernel/signal.c:735 [inline] do_signal+0x1419/0x2240 arch/x86/kernel/signal.c:786 exit_to_usermode_loop+0x26c/0x360 arch/x86/entry/common.c:161 prepare_exit_to_usermode+0x2f6/0x3d0 arch/x86/entry/common.c:196 ret_from_intr+0x26/0x2b RIP: 0033:0x402470 Code: 01 49 83 c5 09 45 39 67 1c 7f ce 48 69 db e8 04 00 00 44 89 b3 04 05 c8 00 48 83 c4 08 5b 5d 41 5c 41 5d 41 5e 41 5f c3 66 90 <53> 48 8b 76 10 89 fb 64 8b 04 25 d0 ff ff ff 85 c0 74 3d 48 8d 86 RSP: 002b:00007fbff76de4b8 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 00007fbff76df6d4 RCX: 0000000000416687 RDX: 00007fbff76de4c0 RSI: 00007fbff76de5f0 RDI: 000000000000000b RBP: 000000000076bfa0 R08: 00007fbff76dea70 R09: 000000000076bfa0 R10: 0000000000000000 R11: 0000000000000000 R12: 00000000ffffffff R13: 0000000000000beb R14: 00000000004ce128 R15: 000000000076bfac