Bug in ecpg lib ?

From: leif(at)crysberg(dot)dk
To: pgsql-general <pgsql-general(at)postgresql(dot)org>
Subject: Bug in ecpg lib ?
Date: 2009-06-24 14:30:26
Message-ID: 32591099.93481245853826465.JavaMail.root@quick
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-general

Hi guys,

I'm using PostgreSQL in a server project that uses many forks and many threads in each forked process.

Almost everytime I do a pthread_cancel() I get a SIGSEGV. I have then linked the libmudflapth into my program to catch the problem sooner and now that reports either 'invalid pointer' or 'double free or corruption' when a thread is cancelled. Typically I have 2 database connection opened before any of the threads are created. I am pretty sure that I'm only using 1 connection in any 1 thread, i.e. only 2 of the threads are doing database access and using each their allocated connection.

After the main thread has done a pthread_cancel() I get a "mudflapth dump" with the following trace back (the abort comes from the mudflapth lib when detecting the bad pointer):

#0 0xffffe405 in __kernel_vsyscall ()
#1 0xf7ca2335 in raise () from /lib32/libc.so.6
#2 0xf7ca3cb1 in abort () from /lib32/libc.so.6
#3 0xf7cdb6ec in ?? () from /lib32/libc.so.6
#4 0xf7ce71ab in free () from /lib32/libc.so.6
#5 0xf7dec061 in free (buf=0x87ed138) at ../../../libmudflap/mf-hooks1.c:241
#6 0xf7ef2b5c in ecpg_sqlca_key_destructor () from /lib32/libecpg.so.6
#7 0xf7dcebb0 in __nptl_deallocate_tsd () from /lib32/libpthread.so.0
#8 0xf7dcf509 in start_thread () from /lib32/libpthread.so.0
#9 0xf7d5008e in clone () from /lib32/libc.so.6

Looking in the ecpg_sqlca_key_destructor(), it seems to me that the sqlca can be deallocated several times !? (I'm not too much into the Postgres code including ecpg, so that is a novice point of view.)

I have tried both pgsql-8.3.5 and pgsql-8.4rc1, with exactly the same result and and on many different Linux systems, mainly Slackware 10.2 and Ubuntu 7. I have on all systems configured and compiled Postgres with this configure line:

./configure --prefix=/usr/local/Packages/pgsql-8.3.5 --with-openssl --enable-thread-safety

Please help,

Leif

Responses

Browse pgsql-general by date

  From Date Subject
Next Message Filip Rembiałkowski 2009-06-24 15:23:07 Re: A question about inheritance and sequence
Previous Message Jack Orenstein 2009-06-24 14:26:46 JDBC prepared statements & server-side prepared statements