INFO: task syz-executor.4:15660 can't die for more than 143 seconds. syz-executor.4 R running task 28960 15660 7480 0x00004006 Call Trace: Showing all locks held in the system: 1 lock held by khungtaskd/1168: #0: ffffffff899befc0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5754 1 lock held by in:imklog/6760: #0: ffff8880a89983f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 1 lock held by syz-executor.4/15660: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1168 Comm: khungtaskd Not tainted 5.7.0-rc1-next-20200415-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:147 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:249 [inline] watchdog+0xde3/0x14e0 kernel/hung_task.c:333 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 15660 Comm: syz-executor.4 Not tainted 5.7.0-rc1-next-20200415-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:validate_chain kernel/locking/lockdep.c:3201 [inline] RIP: 0010:__lock_acquire+0xd27/0x4c50 kernel/locking/lockdep.c:4355 Code: 37 19 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 54 24 30 48 c1 ea 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e f7 34 00 00 8b 45 20 <25> 00 80 04 00 3d 00 00 04 00 0f 84 05 14 00 00 48 c7 c2 14 80 8b RSP: 0018:ffffc900058ef9a8 EFLAGS: 00000046 RAX: 0000000000040504 RBX: ffffffff8c34d8e0 RCX: ffffffff81592b4b RDX: 1ffff11013ea9da6 RSI: 0000000000000008 RDI: ffffffff8c34d920 RBP: ffff88809f54ed10 R08: 0000000000000001 R09: fffffbfff1862751 R10: ffffffff8c313a87 R11: fffffbfff1862750 R12: ffff88809f54e440 R13: 0000000000000000 R14: 0000000000000001 R15: ffffffff8a8b8010 FS: 00007f8db50e7700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbaa195f000 CR3: 00000000889aa000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4934 __mutex_lock_common kernel/locking/mutex.c:956 [inline] __mutex_lock+0x156/0x13c0 kernel/locking/mutex.c:1103 pipe_lock_nested fs/pipe.c:66 [inline] pipe_double_lock+0x171/0x1e0 fs/pipe.c:101 splice_pipe_to_pipe fs/splice.c:1562 [inline] do_splice+0x377/0x1560 fs/splice.c:1141 __do_sys_splice fs/splice.c:1447 [inline] __se_sys_splice fs/splice.c:1427 [inline] __x64_sys_splice+0x2c1/0x330 fs/splice.c:1427 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45c829 Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f8db50e6c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 0000000000507760 RCX: 000000000045c829 RDX: 0000000000000004 RSI: 0000000000000000 RDI: 0000000000000006 RBP: 000000000078c180 R08: 0000000000010000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000bae R14: 00000000004ce7f7 R15: 00007f8db50e76d4