Horton

Re: Server crash due to SIGBUS(Bus Error) when trying to access the memory created using dsm_create().

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Thomas Munro <thomas.munro@enterprisedb.com>, Andres Freund <andres@anarazel.de>, amul sul <sul_amul@yahoo.co.in>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2017-09-25T18:28:29Z
Lists: pgsql-hackers 
Robert Haas <robertmhaas@gmail.com> writes:
> On Mon, Sep 25, 2017 at 10:22 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> I think we don't really have a lot of choice.  I propose applying this
>> as far back as 9.6 --- anyone think differently?

> +1.  If applies to 9.5 and 9.4 without a lot of work, I think we
> should apply it there as well, in case there is out-of-core use of DSM
> (or, in 9.5, also of ParallelContext).

Hmm, so I tested this patch on my RHEL6 box (kernel 2.6.32) and it
immediately fell over with

2017-09-25 14:23:48.410 EDT [325] FATAL:  could not resize shared memory segment "/PostgreSQL.1682054886" to 6928 bytes: Operation not supported

during startup.  I wonder whether we need to round off the request.

			regards, tom lane

Commits

  1. Fix failure-to-read-man-page in commit 899bd785c.

  2. Avoid SIGBUS on Linux when a DSM memory request overruns tmpfs.