INFO: task kworker/u4:2:51 blocked for more than 140 seconds. Not tainted 4.19.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:2 D25056 51 2 0x80000000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x887/0x2040 kernel/sched/core.c:3517 schedule+0x8d/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x92d/0xfe0 kernel/time/timer.c:1794 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common+0x29c/0x470 kernel/sched/completion.c:115 flush_workqueue+0x40b/0x13e0 kernel/workqueue.c:2713 flush_scheduled_work include/linux/workqueue.h:599 [inline] tipc_exit_net+0x38/0x60 net/tipc/core.c:100 ops_exit_list+0xa5/0x150 net/core/net_namespace.c:153 cleanup_net+0x3b4/0x8b0 net/core/net_namespace.c:554 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Showing all locks held in the system: 3 locks held by kworker/u4:2/51: #0: 0000000025803fa4 ((wq_completion)"%s""netns"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 000000002aa88ee4 (net_cleanup_work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 00000000e9f95665 (pernet_ops_rwsem){++++}, at: cleanup_net+0xa8/0x8b0 net/core/net_namespace.c:521 1 lock held by khungtaskd/1570: #0: 00000000b6d60e1f (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441 1 lock held by in:imklog/7835: #0: 000000001c34702b (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 1 lock held by syz-executor.2/8176: #0: 00000000f173e611 (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1826 [inline] #0: 00000000f173e611 (&rq->lock){-.-.}, at: __schedule+0x1f9/0x2040 kernel/sched/core.c:3455 2 locks held by kworker/0:34/13690: #0: 00000000240809c4 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 audit: type=1800 audit(1672476601.588:1139): pid=9318 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed comm="syz-executor.5" name="bus" dev="sda1" ino=14353 res=0 #1: 000000002e0f9063 ((work_completion)(&m->rq)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 2 locks held by kworker/0:35/13691: #0: 00000000240809c4 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 00000000e8d2f1bf ((work_completion)(&m->rq)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 3 locks held by kworker/1:5/25471: #0: 00000000f4f20159 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 00000000fad1a899 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 0000000053b907df (rtnl_mutex){+.+.}, at: addrconf_dad_work+0x9c/0x10a0 net/ipv6/addrconf.c:3989 2 locks held by kworker/u4:12/26149: 2 locks held by kworker/0:0/11015: 2 locks held by kworker/1:0/22656: #0: 00000000240809c4 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 00000000b617407f ((work_completion)(&m->rq)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 3 locks held by kworker/1:2/28794: #0: 00000000240809c4 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 00000000ae289ee5 ((linkwatch_work).work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 0000000053b907df (rtnl_mutex){+.+.}, at: linkwatch_event+0xb/0x60 net/core/link_watch.c:236 2 locks held by syz-executor.4/9263: 2 locks held by syz-executor.0/9261: #0: 0000000053b907df (rtnl_mutex){+.+.}, at: tun_detach drivers/net/tun.c:759 [inline] #0: 0000000053b907df (rtnl_mutex){+.+.}, at: tun_chr_close+0x3a/0x180 drivers/net/tun.c:3323 #1: 00000000a5ca5da0 (rcu_preempt_state.exp_mutex){+.+.}, at: exp_funnel_lock kernel/rcu/tree_exp.h:297 [inline] #1: 00000000a5ca5da0 (rcu_preempt_state.exp_mutex){+.+.}, at: _synchronize_rcu_expedited+0x4dc/0x6f0 kernel/rcu/tree_exp.h:667 1 lock held by syz-executor.1/9309: #0: 0000000053b907df (rtnl_mutex){+.+.}, at: ipv6_route_ioctl+0x21a/0x2f0 net/ipv6/route.c:3725 1 lock held by syz-executor.5/9318: #0: 000000008cd14438 (event_mutex){+.+.}, at: perf_trace_destroy+0x23/0xf0 kernel/trace/trace_event_perf.c:236 2 locks held by syz-executor.3/9333: #0: 000000005b4e5252 (vlan_ioctl_mutex){+.+.}, at: sock_ioctl+0x385/0x5d0 net/socket.c:1111 #1: 0000000053b907df (rtnl_mutex){+.+.}, at: vlan_ioctl_handler+0xb7/0xf00 net/8021q/vlan.c:547 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1570 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x991/0xe60 kernel/hung_task.c:287 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4692 Comm: systemd-journal Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 RIP: 0010:memset_erms+0xb/0x10 arch/x86/lib/memset_64.S:67 Code: 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 f3 aa <4c> 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 01 01 RSP: 0018:ffff8880a0d5fd30 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff88823b843380 RCX: 0000000000000000 RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffff888023737810 RBP: 0000000000000000 R08: 0000000000000000 R09: ffff888023737800 R10: 0000000000000005 R11: 0000000000000000 R12: ffffea00008dcd80 R13: ffff888023736800 R14: 0000000000000000 R15: ffff88823b843380 FS: 00007f68cd41b8c0(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f79ec023000 CR3: 00000000a1169000 CR4: 00000000003406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: cache_init_objs mm/slab.c:2582 [inline] cache_grow_begin+0x52b/0x8a0 mm/slab.c:2709 cache_alloc_refill+0x273/0x340 mm/slab.c:3049 ____cache_alloc mm/slab.c:3132 [inline] __do_cache_alloc mm/slab.c:3354 [inline] slab_alloc mm/slab.c:3389 [inline] kmem_cache_alloc+0x346/0x370 mm/slab.c:3557 getname_flags+0xce/0x590 fs/namei.c:140 getname fs/namei.c:211 [inline] user_path_create fs/namei.c:3696 [inline] do_mkdirat+0x8d/0x2d0 fs/namei.c:3834 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f68cc6d6687 Code: 00 b8 ff ff ff ff c3 0f 1f 40 00 48 8b 05 09 d8 2b 00 64 c7 00 5f 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 b8 53 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e1 d7 2b 00 f7 d8 64 89 01 48 RSP: 002b:00007ffc1177f0f8 EFLAGS: 00000293 ORIG_RAX: 0000000000000053 RAX: ffffffffffffffda RBX: 00007ffc11782010 RCX: 00007f68cc6d6687 RDX: 00007f68cd147a00 RSI: 00000000000001ed RDI: 0000555d4e9038a0 RBP: 00007ffc1177f130 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000069 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ffc11782010 R15: 00007ffc1177f620