[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 64.883562][ T27] audit: type=1800 audit(1583552957.998:25): pid=9317 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 64.919362][ T27] audit: type=1800 audit(1583552957.998:26): pid=9317 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 64.953507][ T27] audit: type=1800 audit(1583552958.008:27): pid=9317 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.15.201' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 83.470136][T10149] general protection fault, probably for non-canonical address 0xdffffc0000000021: 0000 [#1] PREEMPT SMP KASAN [ 83.481915][T10149] KASAN: null-ptr-deref in range [0x0000000000000108-0x000000000000010f] [ 83.490332][T10149] CPU: 0 PID: 10149 Comm: blkid Not tainted 5.6.0-rc3-next-20200228-syzkaller #0 [ 83.499443][T10149] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 83.509523][T10149] RIP: 0010:destroy_workqueue+0x2e/0x6b0 [ 83.515177][T10149] Code: 49 89 fe 41 55 41 54 55 53 48 83 ec 08 e8 8a 6a 26 00 49 8d be 08 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 e0 05 00 00 49 8b 9e 08 01 00 00 48 85 db 74 19 [ 83.535050][T10149] RSP: 0018:ffffc90002f27c30 EFLAGS: 00010206 [ 83.541097][T10149] RAX: dffffc0000000000 RBX: 0000000000000002 RCX: 0000000000000000 [ 83.549068][T10149] RDX: 0000000000000021 RSI: ffffffff814c2af6 RDI: 0000000000000108 [ 83.557086][T10149] RBP: ffff8882189978f0 R08: ffff888096c505c0 R09: fffffbfff185270a [ 83.565044][T10149] R10: fffffbfff1852709 R11: ffffffff8c29384f R12: ffff888218997800 [ 83.573009][T10149] R13: ffff88808dc478a0 R14: 0000000000000000 R15: ffff88808dc47680 [ 83.581004][T10149] FS: 00007fd99f56e740(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 [ 83.590061][T10149] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 83.596946][T10149] CR2: 00007f3095dcd000 CR3: 00000000a4478000 CR4: 00000000001406f0 [ 83.604936][T10149] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 83.612957][T10149] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 83.620923][T10149] Call Trace: [ 83.624225][T10149] __loop_clr_fd+0x185/0x1280 [ 83.628899][T10149] lo_release+0x1ad/0x1e7 [ 83.633237][T10149] ? lo_compat_ioctl+0x110/0x110 [ 83.638160][T10149] __blkdev_put+0x509/0x690 [ 83.642664][T10149] ? freeze_bdev+0x1f0/0x1f0 [ 83.647236][T10149] ? blkdev_put+0x520/0x520 [ 83.651718][T10149] ? blkdev_put+0x85/0x520 [ 83.656246][T10149] ? blkdev_put+0x520/0x520 [ 83.660998][T10149] blkdev_close+0x86/0xb0 [ 83.665308][T10149] __fput+0x2da/0x850 [ 83.669382][T10149] task_work_run+0x13f/0x1b0 [ 83.674135][T10149] exit_to_usermode_loop+0x2fa/0x360 [ 83.679408][T10149] do_syscall_64+0x672/0x790 [ 83.683991][T10149] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 83.689868][T10149] RIP: 0033:0x7fd99ee762b0 [ 83.694269][T10149] Code: 40 75 0b 31 c0 48 83 c4 08 e9 0c ff ff ff 48 8d 3d c5 32 08 00 e8 c0 07 02 00 83 3d 45 a3 2b 00 00 75 10 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 ce 8a 01 00 48 89 04 24 [ 83.713948][T10149] RSP: 002b:00007ffc0a7acc98 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 [ 83.722355][T10149] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fd99ee762b0 [ 83.730317][T10149] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 [ 83.738275][T10149] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 [ 83.746241][T10149] R10: 0000000000000000 R11: 0000000000000246 R12: 000000000164a030 [ 83.754222][T10149] R13: 0000000000000000 R14: 0000000000000003 R15: 0000000000000005 [ 83.762183][T10149] Modules linked in: [ 83.766504][T10149] ---[ end trace 607b7fe0e8c7e1ae ]--- [ 83.772198][T10149] RIP: 0010:destroy_workqueue+0x2e/0x6b0 [ 83.777827][T10149] Code: 49 89 fe 41 55 41 54 55 53 48 83 ec 08 e8 8a 6a 26 00 49 8d be 08 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 e0 05 00 00 49 8b 9e 08 01 00 00 48 85 db 74 19 [ 83.797475][T10149] RSP: 0018:ffffc90002f27c30 EFLAGS: 00010206 [ 83.803563][T10149] RAX: dffffc0000000000 RBX: 0000000000000002 RCX: 0000000000000000 [ 83.811562][T10149] RDX: 0000000000000021 RSI: ffffffff814c2af6 RDI: 0000000000000108 [ 83.819558][T10149] RBP: ffff8882189978f0 R08: ffff888096c505c0 R09: fffffbfff185270a [ 83.827704][T10149] R10: fffffbfff1852709 R11: ffffffff8c29384f R12: ffff888218997800 [ 83.836166][T10149] R13: ffff88808dc478a0 R14: 0000000000000000 R15: ffff88808dc47680 [ 83.844272][T10149] FS: 00007fd99f56e740(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 [ 83.853438][T10149] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 83.860104][T10149] CR2: 00007f3095dcd000 CR3: 00000000a4478000 CR4: 00000000001406f0 [ 83.868290][T10149] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 83.876298][T10149] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 83.884514][T10149] Kernel panic - not syncing: Fatal exception [ 83.891434][T10149] Kernel Offset: disabled [ 83.895758][T10149] Rebooting in 86400 seconds..