#1126447 atop: segfault at 8 (NULL pointer dereference) in Debian 12

Package:
atop
Source:
atop
Description:
Monitor for system resources and process activity
Submitter:
Thomas Damgaard Nielsen
Date:
2026-08-12 07:35:04 UTC
Severity:
normal
#1126447#5
Date:
2026-01-26 09:20:18 UTC
From:
To:
Dear Maintainer,


The atop service crashed with a segmentation fault on Debian 12.

Log snippet: atop[196073]: segfault at 8 ip 000055f29a9f4a80 sp
00007ffcba5be990 error 4 in atop[55f29a9f4000+2d000] likely on CPU 0

Code bytes: > 8b 04 25 08 00 00 00 0f 0b 0f 1f 80 00 00 00 00 41 57 41
56 41 55

The crash seems to be a NULL pointer dereference (accessing address
0x8). This occurred on a standard Debian 12 installation.




   * What led up to the situation?


I use atop to monitor performance and hw utilization of my server.
I typically run atop interactively in a tmux - and I was doing this at
the time of the crash as well.
The atop service is running with default config.


   * What exactly did you do (or not do) that was effective (or
     ineffective)?

I did not do anything specifically. Atop was just running by itself.
Again: Default config purely as it comes from the package.



   * What was the outcome of this action?

N/A.


   * What outcome did you expect instead?

I expect atop to not crash with segfault.
#1126447#10
Date:
2026-01-26 21:27:39 UTC
From:
To:
Hi,

I would like to recommend to update to current Debian stable and to see
whether the issue persists. This might be a bug that was fixd in the
mean time since Debian bookworm was released.

Greetings
Marc