INFO: task syz-executor.3:27917 blocked for more than 140 seconds. Not tainted 4.14.198-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28672 27917 6353 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_timeout+0x80a/0xe90 kernel/time/timer.c:1731 do_wait_for_common kernel/sched/completion.c:91 [inline] __wait_for_common kernel/sched/completion.c:112 [inline] wait_for_common+0x272/0x430 kernel/sched/completion.c:123 ucma_close+0xfc/0x340 drivers/infiniband/core/ucma.c:1749 __fput+0x25f/0x7a0 fs/file_table.c:210 task_work_run+0x11f/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x417901 RSP: 002b:00007ffe83ce8860 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000000417901 RDX: 0000000000000000 RSI: 0000000000000d51 RDI: 0000000000000005 RBP: 0000000000000001 R08: 00000000d5dfcd51 R09: 00000000d5dfcd55 R10: 00007ffe83ce8950 R11: 0000000000000293 R12: 000000000118d9c0 R13: 000000000118d9c0 R14: ffffffffffffffff R15: 000000000118cff4 Showing all locks held in the system: 1 lock held by khungtaskd/1068: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1068 Comm: khungtaskd Not tainted 4.14.198-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+0x1b2/0x283 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x17f 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+0x5b9/0xb40 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: 3652 Comm: systemd-journal Not tainted 4.14.198-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff888094260340 task.stack: ffff888094268000 RIP: 0010:rcu_is_watching+0x0/0xb0 kernel/rcu/tree.c:1126 RSP: 0018:ffff88809426fbb8 EFLAGS: 00000297 RAX: ffff888094260340 RBX: 0000000000000050 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000002 RDI: ffff888094260bc4 RBP: ffff88809426fc78 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000000 R11: ffff888094260340 R12: 00000000fffffffe R13: ffff88809426fc78 R14: ffff88809426fea8 R15: ffff88809426fc78 FS: 00007fcb2ad0b8c0(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcb285c9000 CR3: 00000000948ee000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_unlock include/linux/rcupdate.h:681 [inline] terminate_walk+0x200/0x530 fs/namei.c:626 path_parentat+0x55/0x120 fs/namei.c:2406 filename_parentat+0x176/0x520 fs/namei.c:2420 filename_create+0x8a/0x3f0 fs/namei.c:3657 user_path_create fs/namei.c:3732 [inline] SYSC_mkdirat fs/namei.c:3864 [inline] SyS_mkdirat+0x95/0x270 fs/namei.c:3856 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7fcb29fc7687 RSP: 002b:00007ffe03546b08 EFLAGS: 00000293 ORIG_RAX: 0000000000000053 RAX: ffffffffffffffda RBX: 00007ffe03549b70 RCX: 00007fcb29fc7687 RDX: 0000000000000000 RSI: 00000000000001ed RDI: 00005572cfc9c8c0 RBP: 00007ffe03546b40 R08: 00005572cf57d3e5 R09: 0000000000000018 R10: 0000000000000069 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000001 R14: 00005572cfc9c8c0 R15: 00007ffe03547180 Code: e8 36 5d 38 00 e9 36 ff ff ff e8 2c 5d 38 00 e9 7a ff ff ff e8 22 5d 38 00 e9 51 ff ff ff 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 <53> 48 83 ec 08 65 ff 05 84 e0 b4 7e e8 df 94 b8 01 48 c7 c3 80