Month: March 2017

Recovering from Linux boot failure with fsck

A virtual Linux machine used for development was behaving unreliably.

Programs would fail to start and running program would freeze.

I decided to restart the system, however it failed to start up again.

 

It simply displayed this message:

BusyBox v1.22.1 (Ubuntu 1:1.22.0-15ubuntu1) built-in shell (ash)
Enter 'help' for a list of built-in commands.

(initramfs)

 

I tried to exit the shell, which lead to this message:

/dev/sda1 contains a file system with errors, check forced.
/dev/sda1:
Inodes that were part of a corrupted orphan linked list found.

/dev/sda1: UNEXPECTED INCONSISTENCY; RUN fsck MANUALLY.
        (i.e., without -a or -p options)
fsck exited with status code 4
The root filesystem on /dev/sda1 requires a manual fsck

 

File system corruption seemed to explain the reliability problems and the subsequent boot failure.

Followed the suggestion of running fsck with:

fsck /dev/sda1

 

Accepted all file system repairs suggested by fsck.

(Should have used the -y parameter)

 

Then rebooted the system with:

reboot

 

After the file system repairs the system booted and seemed fully functional.

Conclusion

If a Linux system fails to boot and only displays a BusyBox / initramfs prompt, try exiting the shell.

This may provide information about the actual problem.

Examining BAD_POOL_CALLER (c2) BSOD

My work computer recently crashed again with another BSOD.

 

Checked Event Viewer and found:

Log Name:      System
Source:        Microsoft-Windows-WER-SystemErrorReporting
Event ID:      1001
Level:         Error
Keywords:      Classic
Description:
The computer has rebooted from a bugcheck.  The bugcheck was: 0x000000c2 (0x0000000000000007, 0x000000000000109b, 0x0000000000000000, 0xfffffa800cd9d010). A dump was saved in: C:\Windows\MEMORY.DMP.

 

Examined the memory dump with WinDbg (x64).

Checked for details about the crash with:

!analyze -v

Part of the result:

BAD_POOL_CALLER (c2)
The current thread is making a bad pool request.  Typically this is at a bad IRQL level or double freeing the same allocation, etc.
Arguments:
Arg1: 0000000000000007, Attempt to free pool which was already freed
Arg2: 000000000000109b, (reserved)
Arg3: 0000000000000000, Memory contents of the pool block
Arg4: fffffa800cd9d010, Address of the block of pool being deallocated

Debugging Details:
------------------

POOL_ADDRESS:  fffffa800cd9d010 Nonpaged pool

BUGCHECK_STR:  0xc2_7

DEFAULT_BUCKET_ID:  WIN7_DRIVER_FAULT

PROCESS_NAME:  vlc.exe

CURRENT_IRQL:  2

MODULE_NAME: avgtdia

IMAGE_NAME:  avgtdia.sys

 

Examined the call stack with:

kp

Result:

Child-SP          RetAddr           Call Site
fffff880`0db9b1f8 fffff800`031c3bf9 nt!KeBugCheckEx
fffff880`0db9b200 fffff880`01f729c5 nt!ExAllocatePoolWithTag+0x1951
fffff880`0db9b2b0 fffff880`04272775 avgtdia+0xb9c5
fffff880`0db9b330 fffff880`042407bb afd! ?? ::GFJBLGFE::`string'+0xd64c
fffff880`0db9b550 fffff800`033b028e afd!AfdFastIoDeviceControl+0x7ab
fffff880`0db9b8c0 fffff800`033b0896 nt!IopXxxControlFile+0x6be
fffff880`0db9ba00 fffff800`0308c693 nt!NtDeviceIoControlFile+0x56
fffff880`0db9ba70 00000000`73b12e09 nt!KiSystemServiceCopyEnd+0x13
00000000`045af0f8 00000000`00000000 0x73b12e09

 

The driver avgtdia.sys seemed to cause the crash.

 

Examined information about the avgtdia driver with:

lm v m avgtdia

Result:

start             end                 module name
fffff880`01f67000 fffff880`01fad000   avgtdia    (no symbols)
Loaded symbol image file: avgtdia.sys
Image path: \SystemRoot\system32\DRIVERS\avgtdia.sys
Image name: avgtdia.sys
Timestamp:        Wed Jul 27 15:24:36 2016 (5798B614)
CheckSum:         00053AED
ImageSize:        00046000
Translations:     0000.04b0 0000.04e4 0409.04b0 0409.04e4

 

Discovered that avgtdia.sys was: AVG Network connection watcher

 

This made me suspect that other BSOD crashes were also caused by AVG Internet Security:

Examining PFN_LIST_CORRUPT (4e) and PAGE_FAULT_IN_NONPAGED_AREA (50) BSOD

 

I decided to uninstall AVG Internet Security using: AVG Remover

Installed replacement: Avira Antivirus

 

I used to experience 2 BSOD crashes per week on this computer.

After uninstalling AVG Internet Security, the computer has been running for 1 week without any crashes…

I hope that the root cause has been identified and that the computer will finally be stable and reliable.

Conclusion

Common causes for computer stability problems are failing hard disks, defective memory and buggy drivers.

It seems that some antivirus products can also cause stability problems, possibly combined with specific drivers or other system level software.