Why Coredump files is not generating here?

Question

I have a situation here, a few days back I was able to see a core- dump file on my target board, I have enabled the core-dump generation by adding "ulimit -c unlimited" to my /etc/profile.

But then someone told me, this will only take affect for program launched from a login shell, not for processes/services started by systemd, etc. and the ulimits are set at another location.

So I changed /etc/limits file and added ulimit -c unlimited line, but still I could not see core-dump file.

I am running kill -9 $$ to generate segmentation fault and it in turn will generate core-dump file as it was doing earlier.

We tried changing "/proc/sys/kernel/core_pattern" file and running ulimit -c unlimited explicitly but this was not enough.

Where we are going wrong?

The `-9` to the `kill` command is the `KILL` signal, and will simply terminate the process without a core-dump. — Some programmer dude, Aug 21 '13 at 10:15
So @JoachimPileborg what you suggest ,how can I use kill command in my case?? — Amit Singh Tomar, Aug 21 '13 at 10:17
See e.g. [this question and answers](http://stackoverflow.com/q/6561194/440558). — Some programmer dude, Aug 21 '13 at 10:19
I tried kill -3 $$ but I am still not getting any core dump file. — Amit Singh Tomar, Aug 21 '13 at 10:28
Also, why use `$$`? It expands to the pid of the *shell* you're running in. — Some programmer dude, Aug 21 '13 at 10:30
Yes @JoachimPileborg , I am expecting killing shell will give me a segmentation fault .Is it wrong or what?? — Amit Singh Tomar, Aug 21 '13 at 10:33
If you are using bash, you should read [the manual](https://www.gnu.org/software/bash/manual/html_node/Signals.html) where it says: "In all cases, Bash ignores SIGQUIT." — Some programmer dude, Aug 21 '13 at 10:42
@JoachimPileborg core are generating now, used kill -6 $$ but problem I have to run ulimit -c unlimited manually,its not taking it from /etc/limits file ,any idea?? — Amit Singh Tomar, Aug 21 '13 at 10:53
Because the `/etc/limits` file should not contain the *command*, it has a [different format](http://swoolley.org/man.cgi/5/limits). Besides, it's probably not used on modern Linux distros. Instead check `/etc/security/limits.conf` and its [manual page](http://linux.die.net/man/5/limits.conf). — Some programmer dude, Aug 21 '13 at 11:03
@JoachimPileborg I don't have etc/security/limits.conf in my filesystem ,is there any way to set it in /etc/limits like set core=-1 — Amit Singh Tomar, Aug 21 '13 at 11:18
Linux kernels can be configured without `core` support. See that **CONFIG_ELF_CORE** is set for your Linux kernel. Then the standard *user space* information applies. — artless noise, Sep 12 '13 at 17:51

score 9 · Accepted Answer · answered Sep 12 '13 at 20:26

9

kill -9 will not generate a core file. The command kill -l gives a list of supported signals. kill -6 or kill -SIGABRT should produce a core file. As well as most other signals such as kill -BUS, kill -SEGV, etc.

answered Sep 12 '13 at 20:26

artless noise

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score 5 · Answer 2 · answered Apr 27 '15 at 16:07

5

kill -11 always works for me. 11 is SIGSEGV (invalid memory reference)

answered Apr 27 '15 at 16:07

Danish Rizvi

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But that is a bad idea. Some weird programs might *catch* `SIGSEGV`; `SIGABRT` is much more conventional, and the few programs catching it knows about it meaning. – Basile Starynkevitch Jul 18 '15 at 06:51

score 2 · Answer 3 · edited Jul 18 '15 at 13:06

You have to first off enable user limits settings to ensure that core files can be created.

ulimit -c unlimited

Application user must run as and before you start the application in the same session. This setting is inherited by the application, so what ever the ulimit is set as before starting the application is what the ulimit setting will be for the application (unless a start script changes it).

Basile Starynkevitch · Answer 4 · 2015-07-18T14:16:50.370

In addition of the other answers, you might also use gcore(1) to generate a core dump of some running process.

But if using kill(1) command (or the underlying kill(2) syscall, e.g. from some ad-hoc program), I recommend using SIGABRT (the signal that abort(3) send to itself after unblocking it), as documented in the signal(7).

Beware, a program can usually forbid core dumping, e.g. by calling setrlimit(2) with RLIMIT_CORE set to 0 or handling or ignoring some signals (with e.g. sigaction(2)...).

Why Coredump files is not generating here?

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