Re: [Sqlrelay-discussion] memory corruption, apache segfault

[David M. <dav...@fi...>]

Well, I said I'd look into this problem, then I misplaced the email
until today :/

Are you still having this problem?

David Muse
dav...@fi...


On Fri, 2005-08-19 at 07:48 +0300, Ionut Ciocirlan wrote:
> Hi,
> 
> Nasty problem I ran into:
> 
> I'm running sqlrelay-0.36.4 compiled against oracle instant client-10.1.0.4,
> on fedora core 3, glibc-2.3.5; apache-2.0.53 / php-4.3.11.
> 
> Trying to fetch text containing several utf-8 characters (namely diacritics)
> from clobs sometimes crashes apache, with glibc memory errors.
> 
> NLS_LANG is .AL32UTF8 for both Oracle and SQL Relay; data posted into Apache
> is in UTF-8.
> 
> Apache crashes with various messages:
> 
> *** glibc detected *** malloc(): memory corruption: 0x094d6f20 ***
> [notice] child pid 4005 exit signal Aborted (6)
> 
> *** glibc detected *** free(): invalid next size (fast): 0x0a174a80 ***
> [notice] child pid 15277 exit signal Aborted (6)
> 
> *** glibc detected *** double free or corruption (!prev): 0x094d0ee0 ***
> [notice] child pid 4004 exit signal Aborted (6)
> 
> *** glibc detected *** double free or corruption (out): 0x0948c598 ***
> [notice] child pid 4062 exit signal Aborted (6)
> [notice] child pid 4009 exit signal Segmentation fault (11)
> 
> The most common error is the first (memory corruption). On almost all
> occasions, the client browser gets a zero-sized reply. I'd say it's random,
> but on fast reruns it happens ~ 5 out of 6 times. Sometimes (rarely) i get
> no crash, but apache hangs without replying, and the browser hangs waiting
> for an answer.
> 
> Reproduce this by inserting characters 'z ăîşţâ y ĂÎŞŢÂ x' in a clob column.
> If it doesn't reproduce add this strign several more times and mix it with
> various other text.
> 
> So, this happens only on clob columns (never on char/varchar):
> 
> Fetching (illegally?) in non-lob mode crashes at sqlrcur_sendQuery:
> 
> $query = 'select column from table where id = xx';
> sqlrcur_sendQuery($cur,$query);
> ---- crash
> 
> Clob fetching crashes at sqlrcur_executeQuery:
> 
> $query = 'begin
> select column into :outvar from table where where id = xx;
> end;'
> sqlrcur_prepareQuery($cur, $query);
> sqlrcur_defineOutputBindClob($cur, 'outvar');
> sqlrcur_executeQuery($cur);
> ---- crash
> 
> 
> The memory corruption issues seem to be pretty real: it reflects mainly in a
> flash communication server running on the same machine, that after several
> such events starts behaving erratically. Sshd and samba get erratic too
> (connections lost etc.). Also, after several hours of testing/debugging, my
> kernel Oopsed. And just now network connectivity went into oblivion. The
> only solution to restoring normal operation seems to be rebooting.
> 
> Conclusions so far:
> - not a machine problem; memtested the hell out of the ram;
> - not an oracle/oci/glibc problem; i recompiled php's oci8 extension against
> the same oracle instant client libs, and i get the expected output, plus no
> crashes;
> - i also recompiled sqlrelay against the 9.1 oracle installation; same
> results;
> - might be a problem that appeared since 0.34 (we did some extensive testing
> back then, and it all worked out fine); i wanted to test now on 0.34 too,
> but for some reason it now fails to compile right from the start
> 
> I hope this will be easy to reproduce / repair.....
> 
> Regards,
> Ionut
> 
> 
> 
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