Horton

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

Thomas Munro <thomas.munro@enterprisedb.com>

View thread View on postgr.es
From: Thomas Munro <thomas.munro@enterprisedb.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Robert Haas <robertmhaas@gmail.com>, Andres Freund <andres@anarazel.de>, amul sul <sul_amul@yahoo.co.in>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2017-09-25T20:42:59Z
Lists: pgsql-hackers 
On Tue, Sep 26, 2017 at 9:13 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> I wrote:
>> Rather than dig into the guts of glibc to find that out, though, I think
>> we should just s/fallocate/posix_fallocate/g on this patch.  The argument
>> for using the former seemed pretty thin to begin with.
>
> Pushed with that change; we'll soon see what the buildfarm thinks.

Thanks.

> I suspect that the provisions for EINTR and ENOSYS errors may now be
> dead code, since the Linux man page for posix_fallocate mentions
> neither.  They're not much code though, and POSIX itself *does*
> list EINTR, so I'm hesitant to muck with that.

Ah, it all makes sense now that I see the fallback strategy section of
the posix_fallocate() man page.  I was unaware that there were kernel
releases that had the syscall but lacked support in tmpfs.  Thanks for
testing and fixing that.

-- 
Thomas Munro
http://www.enterprisedb.com

Commits

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

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