Re: How do I get a coredump file from an application?

On Mon, Oct 4, 2021 at 12:01 PM Yuri <yuri@aetern.org> wrote:

> Odhiambo Washington wrote:
> > Hi
> >
> > root@gw:/var/log/exim # freebsd-version -kru
> > 13.0-RELEASE-p4
> > 13.0-RELEASE-p4
> > 13.0-RELEASE-p4
> >
> >
> > I have my MTA (Exim) crushing, with the following message in its
> panic.log:
> >
> > 2021-10-01 04:10:58 SIGSEGV (maybe attempt to write to immutable memory)
> > 2021-10-01 04:11:26 SIGSEGV (maybe attempt to write to immutable memory)
> > 2021-10-01 04:11:30 SIGSEGV (maybe attempt to write to immutable memory)
> > 2021-10-01 04:11:35 SIGSEGV (maybe attempt to write to immutable memory)
> >
> > I need to obtain a coredump file from the crashing process for debugging
> > purposes.
> >
> > I have manually compiled the application with the following option:
> > CC=clang -ggdb
> > CXX=clang++
> > CPP=clang-cpp
>
> Don't.
>
> Use the following knob documented in ports(7) and (somewhat more
> verbose) in /usr/ports/Mk/bsd.port.mk:
>
> Hello Yuri,

I am not using the port. I am doing a manual compile for a version that has
not yet hit the ports.



> # WITH_DEBUG    - If set, debugging flags are added to CFLAGS and the
> #                 binaries don't get stripped by INSTALL_PROGRAM or
> #                 INSTALL_LIB. Besides, individual ports might
> #                 add their specific to produce binaries for debugging
> #                 purposes. You can override the debug flags that are
> #                 passed to the compiler by setting DEBUG_FLAGS. It is
> #                 set to "-g" at default.
>
>
> > With the hopes that the binary will then come with debugging symbols.
> >
> > Additionally, I have done the following:
> >
> > mkdir -p /var/coredumps
> > chmod 1777 /var/coredumps
> >
> > Added the following to /etc/sysctl.conf:
> >
> > kern.corefile=/var/coredumps/%U/%N.core
> > kern.coredump=1
> >
> > And finally:
> >
> > sysctl -w kern.coredump=1
> > sysctl -w kern.corefile=/var/coredumps/%U/%N.core
> > sysctl -w kern.sugid_coredump=1 (this actually seems to be the default)
> >
> > Is this all that I need to do or am I missing something crucial in this
> > endeavor?
>
> Never used exim so guessing - you likely need to tell exim to actually
> dump the core.
>

That's exactly what I want, but don't know how to do.


-- 
Best regards,
Odhiambo WASHINGTON,
Nairobi,KE
+254 7 3200 0004/+254 7 2274 3223
"Oh, the cruft.", egrep -v '^$|^.*#' :-)