Re: Segmentation fault with core dump - Mailing list pgsql-general

From Alvaro Herrera
Subject Re: Segmentation fault with core dump
Date
Msg-id 20180110173742.bvsk6rl4srprzsp4@alvherre.pgsql
Whole thread Raw
In response to Re: Segmentation fault with core dump  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Segmentation fault with core dump  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general
Tom Lane wrote:
> Glauco Torres <torres.glauco@gmail.com> writes:
> > (gdb) bt
> > #0  ckpt_buforder_comparator (pa=pa@entry=0x7f6fa9ef4b2c,
> > pb=pb@entry=0x1be06d2d06644)
> > at bufmgr.c:4137
> > #1  0x0000000000801268 in med3 (a=0x7f6fa9ef4b2c "\177\006",
> > b=0x1be06d2d06644 <Address 0x1be06d2d06644 out of bounds>,
> > c=0x2fc9dfbb1815c <Address 0x2fc9dfbb1815c out of bounds>, cmp=0x6a4d20
> > <ckpt_buforder_comparator>)
> >     at qsort.c:107
> > #2  0x0000000000801621 in pg_qsort (a=0x7f6fa9ef4b2c, a@entry=0x7f6fa9ea8380,
> > n=<optimized out>, es=es@entry=20, cmp=cmp@entry=0x6a4d20
> > <ckpt_buforder_comparator>) at qsort.c:157
> > #3  0x00000000008015e2 in pg_qsort (a=0x7f6fa9ea8380, n=<optimized out>,
> > n@entry=111473, es=es@entry=20, cmp=cmp@entry=0x6a4d20
> > <ckpt_buforder_comparator>) at qsort.c:203
> > #4  0x00000000006a81cf in BufferSync (flags=flags@entry=128) at
> > bufmgr.c:1863
> 
> Hm.  I'm not normally one to jump to the conclusion that something is a
> compiler bug, but it's hard to explain this stack trace any other way.
> The value of "n" passed to the inner invocation of pg_qsort should not
> have been more than 29914, but working from either the value of d or the
> value of pn leads to the conclusion that it was 0x7f6fa9f3a470, which
> looks a lot more like an address in the array than a proper value of n.
> 
> I suppose this might be due to a corrupted copy of the postgres executable
> rather than an actual compiler bug.  Did you build it yourself?

Hmm, is this something that can be explained by using a different
postgres executable in GDB than the one that produced the core file?

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


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