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Posted to dev@httpd.apache.org by Henrik Nordstrom <hn...@squid-cache.org> on 2006/07/22 23:34:06 UTC
Re: apache 2.2 crashes at the start time in mod_dbd.c then
preparing AuthDBDUserPWQuery
lör 2006-07-22 klockan 18:00 +0100 skrev Nick Kew:
> #3 0x08081d67 in ap_dbd_prepare (s=0x8daf5a0, query=0xffffffff <Address
> 0xffffffff out of bounds>, label=0xffffffff <Address 0xffffffff out of
> bounds>)
> at mod_dbd.c:150
Note: Could maybe be -O2 or higher optimizing away the variables when
they are no longer needed. Seen such things happen very often on many
platforms. Does not need to indicate a bug or even a problem..
Regards
Henrik
Re: apache 2.2 crashes at the start time in mod_dbd.c then
preparing AuthDBDUserPWQuery
Posted by Henrik Nordstrom <hn...@squid-cache.org>.
sön 2006-07-23 klockan 00:10 +0100 skrev Nick Kew:
> But if you look at the full traceback and crossreference it to the
> source, I think that looks improbable. Do you have sufficient gcc/gdb
> expertise to shed real light on this?
Not really, only experience..
From what I have seen the causes to significantly garbled/nonsense
arguments in stack traces is
7 of 10 -O2 somehow messing with the arguments or otherwise making gdb
confused
2 of 10 smashed stacks in the called function
1 of 10 bugs in the calling function or earlier actually passing
non-sense data to the function.
The first and last can be identified by going up to the calling function
and inspecting what the arguments should have been.
The middle by hexdumping the stack contents, and looking at matching
usage of nearby local arrays.
Regards
Henrik
Re: apache 2.2 crashes at the start time in mod_dbd.c then preparing AuthDBDUserPWQuery
Posted by Nick Kew <ni...@webthing.com>.
On Saturday 22 July 2006 22:34, Henrik Nordstrom wrote:
> lör 2006-07-22 klockan 18:00 +0100 skrev Nick Kew:
> > #3 0x08081d67 in ap_dbd_prepare (s=0x8daf5a0, query=0xffffffff <Address
> > 0xffffffff out of bounds>, label=0xffffffff <Address 0xffffffff out of
> > bounds>)
> > at mod_dbd.c:150
>
> Note: Could maybe be -O2 or higher optimizing away the variables when
> they are no longer needed. Seen such things happen very often on many
> platforms. Does not need to indicate a bug or even a problem..
That was my thought with the first traceback, when I saw a potential
bug with mixing per-vhost and per-directory configuration, and Brian
(and coincidentally someone else yesterday on IRC) reported what
appeared to be the same bug.
But if you look at the full traceback and crossreference it to the
source, I think that looks improbable. Do you have sufficient gcc/gdb
expertise to shed real light on this?
--
Nick Kew