From: | Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> |
---|---|
To: | Andres Freund <andres(at)anarazel(dot)de> |
Cc: | pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: more backtraces |
Date: | 2019-12-04 20:31:01 |
Message-ID: | 737b4309-57a2-2a65-fe84-59f84d0abc4d@2ndquadrant.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On 2019-12-04 20:59, Andres Freund wrote:
> On 2019-12-04 20:45:25 +0100, Peter Eisentraut wrote:
>> In the previous discussions on backtrace support, some people asked for
>> backtraces in more situations. Here is a patch that prints backtraces on
>> SIGABRT, SIGBUS, and SIGSEGV signals. SIGABRT includes assertions and
>> elog(PANIC).
>
> Hm. Can we really do that somewhat reliably like this?
I've seen reputable programs that do all kinds of things in SIGSEGV
handlers, including running user-defined programs, without taking any
special precautions. So it seems possible in general.
> I'd suspect that
> there'll be some oddities e.g. for stack overflows if done this way. To
> my knowledge it's not a good idea to intercept SIGBUS/SIGSEGV without
> using a separate signal stack (cf. sigaltstack) - but using a separate
> stack could also make it harder to determine a correct backtrace?
Didn't know about that, but seems useful. I'll look into it.
> It'd be bad if the addition of backtraces for SEGV/BUS suddenly made it
> harder to attach a debugger and getting useful results. Even
> disregarding the previous concerns, we'll get less useful debugger
> interactions due to this, e.g. for things like null pointer derefs,
> right?
The backtrace and level of detail jumping around between frames I get in
lldb looks the same as without this. But it might depend.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
From | Date | Subject | |
---|---|---|---|
Next Message | Tom Lane | 2019-12-04 20:36:19 | Re: Dumping/restoring fails on inherited generated column |
Previous Message | Peter Eisentraut | 2019-12-04 20:17:21 | Re: Dumping/restoring fails on inherited generated column |