INFO: task syz-executor.2:32590 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.2 D28912 32590 6371 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: 0033:0x4177b1 RSP: 002b:00007ffc15fce440 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000005 RCX: 00000000004177b1 RDX: 0000000000000000 RSI: 000000000000086e RDI: 0000000000000004 RBP: 0000000000000001 R08: 00000000216a486e R09: 00000000216a4872 R10: 00007ffc15fce520 R11: 0000000000000293 R12: ffffffffffffffff R13: 000000000008ec64 R14: 00000000000003e8 R15: 000000000118bf2c Showing all locks held in the system: 1 lock held by khungtaskd/1065: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 1 lock held by in:imklog/5982: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0x1fb/0x2b0 fs/file.c:769 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1065 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: 5986 Comm: rs:main Q:Reg Not tainted 4.14.198-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8880a83e8340 task.stack: ffff88808a328000 RIP: 0010:schedule_debug kernel/sched/core.c:3198 [inline] RIP: 0010:__schedule+0xf6/0x1de0 kernel/sched/core.c:3308 RSP: 0018:ffff88808a32f940 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 1ffff11011465000 RSI: ffffffff86e462c0 RDI: ffff8880a83e8358 RBP: ffff88808a32f9f0 R08: ffffffff8a098a18 R09: 0000000000000000 R10: 0000000000000000 R11: ffff8880a83e8340 R12: 000000000002b580 R13: ffff8880aea2b580 R14: ffff88808a328000 R15: ffff8880a83e8340 FS: 00007f285d7c2700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3cb4135018 CR3: 00000000a995d000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: schedule+0x8d/0x1b0 kernel/sched/core.c:3428 freezable_schedule include/linux/freezer.h:172 [inline] futex_wait_queue_me+0x2e0/0x590 kernel/futex.c:2722 futex_wait+0x1b9/0x530 kernel/futex.c:2837 do_futex+0x123/0x1930 kernel/futex.c:3920 SYSC_futex kernel/futex.c:3980 [inline] SyS_futex+0x1da/0x290 kernel/futex.c:3948 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f286020317f RSP: 002b:00007f285d7c1c70 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f286020317f RDX: 000000000000073f RSI: 0000000000000080 RDI: 000055eda619528c RBP: 000055eda6195288 R08: 000055eda6195000 R09: 000000000000039f R10: 0000000000000000 R11: 0000000000000246 R12: 00007f285d7c1cd0 R13: 0000000000000000 R14: 000055eda44dc290 R15: 0000000000000000 Code: 18 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 c3 18 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b 77 18 4c 89 f2 48 c1 ea 03 80 3c 02 00 <0f> 85 91 1a 00 00 49 81 3e 9d 6e ac 57 0f 85 c5 1c 00 00 65 8b