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
catchthe 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'monly using 1 connection in any 1 thread, i.e. only 2 of the threads are doing database access and using each their
allocatedconnection.
After the main thread has done a pthread_cancel() I get a "mudflapth dump" with the following trace back (the abort
comesfrom 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
nottoo 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