From: Andrew Gierth <andrew@tao11.riddles.org.uk>
To: Palle Girgensohn <girgen@FreeBSD.org>
Cc: Peter <pmc@citylink.dinoex.sub.org>
Cc: pgsql-admin@postgresql.org, "pgsql\@freebsd.org" <pgsql@FreeBSD.org>
Subject: Re: Upgrade 10.5->10.6 : db crash BUS ERROR (sig 10), reproducible
Date: Thu, 07 Mar 2019 23:30:19 +0000
Message-ID: <87tvgeb796.fsf@news-spur.riddles.org.uk> (raw)
In-Reply-To: <E4B6F953-A971-4791-8355-BC74A167A52A@FreeBSD.org>
References: <20190307140421.GA8362@gate.oper.dinoex.org>
<874l8ed31p.fsf@news-spur.riddles.org.uk>
<E4B6F953-A971-4791-8355-BC74A167A52A@FreeBSD.org>
>>>>> "Palle" == Palle Girgensohn <girgen@FreeBSD.org> writes:
>> Clang's __builtin_isinf(x) function, which is supposed to test if x is
>> infinite, does not work reliably on i386 when the x87 registers are used
>> for floating point. It does work if the SSE2 registers are used instead,
>> which clang will do if the -msse2 option is used. The downside of course
>> is that the code will no longer run on CPUs that are old enough to vote.
Palle> For this reason, we build i386 with gcc starting with version
Palle> 10.6. the CFLAGS+=--msse2 was not realiable for all CPU:s since
Palle> not all i386 CPU:s support SSE2.
Palle> We had one report of a user who had SSE2 flag still on (int
Palle> /etc/make.conf) when building, and got the same problem.
Palle> [https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=236025
Palle> <https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=236025;]
The user in that bug report was using a Pentium 4, which supports SSE2,
so it's not the lack of SSE2 that caused the problem.
Furthermore, the crash was in XLogReadRecord, which does not use floats.
So I'm going to guess that your bug 236025 is actually an alignment
problem, with the compiler making some assumption about alignment that
we're violating. I'll investigate and see what I can find.
--
Andrew.
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-admin@postgresql.org
Cc: andrew@tao11.riddles.org.uk, girgen@FreeBSD.org, pmc@citylink.dinoex.sub.org, pgsql@FreeBSD.org
Subject: Re: Upgrade 10.5->10.6 : db crash BUS ERROR (sig 10), reproducible
In-Reply-To: <87tvgeb796.fsf@news-spur.riddles.org.uk>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox