INFO: task syz-executor.4:28310 blocked for more than 140 seconds. Not tainted 4.14.195-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28672 28310 6374 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: 0033:0x416f01 RSP: 002b:00007fff9eefd5c0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000416f01 RDX: 0000001b31c20000 RSI: 000000000000086f RDI: 0000000000000003 RBP: 0000000000000001 R08: 00000000216a486e R09: 00000000216a4872 R10: 00007fff9eefd6b0 R11: 0000000000000293 R12: 0000000001190528 R13: 00000000000c2638 R14: ffffffffffffffff R15: 000000000118cf4c Showing all locks held in the system: 1 lock held by khungtaskd/1067: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 1 lock held by in:imklog/6037: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0x1fb/0x2b0 fs/file.c:769 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1067 Comm: khungtaskd Not tainted 4.14.195-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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3640 Comm: systemd-journal Not tainted 4.14.195-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff888094946040 task.stack: ffff888094948000 RIP: 0010:trace_lock_acquire include/trace/events/lock.h:13 [inline] RIP: 0010:lock_acquire+0x139/0x3f0 kernel/locking/lockdep.c:3997 RSP: 0018:ffff88809494f908 EFLAGS: 00000093 RAX: 0000000000000001 RBX: ffff8880916c55a8 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: ffffffff86e46100 RDI: ffffffff879d2d68 RBP: ffffffff87d84e60 R08: 0000000000000002 R09: 0000000000000000 R10: 0000000000000000 R11: ffff888094946040 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000002 R15: 0000000000000000 FS: 00007f4fcbab58c0(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4fc911a008 CR3: 0000000094967000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_lock_acquire include/linux/rcupdate.h:242 [inline] rcu_read_lock include/linux/rcupdate.h:629 [inline] avc_has_perm_noaudit+0xa7/0x2a0 security/selinux/avc.c:1106 selinux_inode_permission+0x380/0x580 security/selinux/hooks.c:3106 security_inode_permission+0xa8/0xf0 security/security.c:698 __inode_permission+0xc5/0x2f0 fs/namei.c:434 inode_permission fs/namei.c:476 [inline] may_lookup fs/namei.c:1711 [inline] link_path_walk+0x16f/0x10a0 fs/namei.c:2097 path_lookupat+0xcb/0x780 fs/namei.c:2342 filename_lookup+0x18a/0x510 fs/namei.c:2377 user_path_at include/linux/namei.h:57 [inline] SYSC_faccessat fs/open.c:403 [inline] SyS_faccessat+0x21b/0x680 fs/open.c:353 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f4fcad719c7 RSP: 002b:00007ffd861baa68 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007ffd861bda90 RCX: 00007f4fcad719c7 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000558caa3b49a3 RBP: 00007ffd861babb0 R08: 0000558caa3aa3e5 R09: 0000000000000018 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000558caaa2d8c0 R15: 00007ffd861bb0a0 Code: 00 00 c7 83 84 08 00 00 01 00 00 00 e9 e1 00 00 00 65 8b 05 ba 2c ba 7e 83 f8 3f 0f 87 02 02 00 00 89 c0 48 0f a3 05 4f 7b 4b 07 <0f> 82 b5 01 00 00 4c 8b 4c 24 08 44 89 ea 6a 00 48 89 ef 6a 00