audit: type=1804 audit(1599552502.073:281): pid=7218 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op=invalid_pcr cause=ToMToU comm="syz-executor.0" name="file0" dev="sda1" ino=17023 res=1 NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 INFO: task syz-executor.5:7154 blocked for more than 140 seconds. Not tainted 4.19.143-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28344 7154 6483 0x00000004 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:1801 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:2715 nbd_start_device_ioctl drivers/block/nbd.c:1267 [inline] __nbd_ioctl drivers/block/nbd.c:1338 [inline] nbd_ioctl+0x759/0xbe0 drivers/block/nbd.c:1378 __blkdev_driver_ioctl block/ioctl.c:303 [inline] blkdev_ioctl+0x5cb/0x1a7e block/ioctl.c:601 block_ioctl+0xe9/0x130 fs/block_dev.c:1896 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45d5b9 Code: Bad RIP value. RSP: 002b:00007f2d5e990c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000000129c0 RCX: 000000000045d5b9 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 000000000118cf78 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007fffb82fd2df R14: 00007f2d5e9919c0 R15: 000000000118cf4c Showing all locks held in the system: 1 lock held by khungtaskd/1090: #0: 00000000e2519514 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4440 1 lock held by in:imklog/6144: #0: 00000000736d53ea (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 2 locks held by kworker/u5:2/6490: #0: 00000000e1114ad5 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2126 #1: 00000000236e971d ((work_completion)(&args->work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2130 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1090 Comm: khungtaskd Not tainted 4.19.143-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+0x1fc/0x2fe lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1a6/0x1eb 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: 3707 Comm: systemd-journal Not tainted 4.19.143-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:slab_alloc mm/slab.c:3394 [inline] RIP: 0010:kmem_cache_alloc+0xef/0x370 mm/slab.c:3557 Code: 00 00 0f 85 df 01 00 00 48 83 3d d3 d6 32 07 00 0f 84 5f 02 00 00 4c 89 ff 57 9d 0f 1f 44 00 00 e8 d6 63 cf ff 41 0f 18 0c 24 c7 80 74 09 4d 85 e4 0f 85 5d 02 00 00 8b 15 09 0b 0f 08 4c 89 RSP: 0018:ffff888093d0fe10 EFLAGS: 00000282 RAX: 0000000000000007 RBX: 00000000006000c0 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000282 RBP: 00000000006000c0 R08: ffffffff8b40f3b0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88808fa77e00 R13: ffff88821bc337c0 R14: ffff88821bc337c0 R15: 0000000000000282 FS: 00007f33396e28c0(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3336c8d000 CR3: 0000000094296000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: prepare_creds+0x39/0x510 kernel/cred.c:255 do_faccessat+0x94/0x7a0 fs/open.c:359 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f333899e9c7 Code: 83 c4 08 48 3d 01 f0 ff ff 73 01 c3 48 8b 0d c8 d4 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 b8 15 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 d4 2b 00 f7 d8 64 89 01 48 RSP: 002b:00007ffc9f353068 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007ffc9f355f80 RCX: 00007f333899e9c7 RDX: 00007f333940fa00 RSI: 0000000000000000 RDI: 0000563a5bc139a3 RBP: 00007ffc9f3530a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ffc9f355f80 R15: 00007ffc9f353590