Hi Laurenz, Thanks for the suggestion. It sure wasn't easy, but I should have done that right away. It turned out not to be in the ecpg module, but somewhere in my own code (of course ;-) ). At least I haven't been able to reproduce it in a simple example and I haven't figured out where in my own code yet either. Leif ----- "Albe Laurenz" <laurenz.albe@xxxxxxxxxx> wrote: > leif@xxxxxxxxxxx wrote: > > 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 > > Could you create a small sample program that reproduces the bug? > > That would make it easier for me or somebody else to do something > about it. > > Yours, > Laurenz Albe -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
