Re: [exim] 4.95-RC0 - SIGSEGV (maybe attempt to write to imm…

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Author: Jeremy Harris
To: exim-users
Subject: Re: [exim] 4.95-RC0 - SIGSEGV (maybe attempt to write to immutable memory) & other oddities
On 08/10/2021 15:42, Andrew Colin Kissa via Exim-users wrote:
> I am seeing this intermittently on a Linux system not FreeBSD.

That is very useful info; thanks.

> I am willing to test this, any pointers on getting the info you want to
> determine the cause ?

Enable coredumps for suid processes, per core(5). You may also need
to ensure that whatever is starting the exim is question (systemd or
similar for the daemon and smtp-accept-initiated delivery procs;
a user for command-line sourced mail initiation) is *not* limiting
core file size to zero ("ulimit" in the shell manpage).

Also, if your system runs abrt then the corefile might get stolen by it
and put somewhere you didn't initially expect (check the abrt config
in /etc).

Once you get a coredump file, feed it to gdb and get a stack trace.

If you're running a self-built binary of exim, building with "-O0 -ggdb"
will get us more detail in the stack trace.

Don't forget to disable suid coredumps again afterwards.