We are getting a backend crash after issueing a load command. It's
pretty easy to recreate -- so easy that I'm not sure that there is
something being overlooked. This is on pg 8.2 roughly two weeks old.
Basic m.o. is:
1. create pic .so
2. load .so and call a function in it (from psql).
3. recompile .so with no changes to source
4. load again and crash. note that merely touching the file and not
recompiling does not cause a crash...example stack trace:
Process 4808 attached - interrupt to quit
recv(8, "Q\0\0\0\35load \'/pgtest/pgfuncs\'\n;\0", 8192, 0) = 30
gettimeofday({1164652467, 63440}, NULL) = 0
write(2, "LOG: statement: load \'/pgtest/p"..., 43) = 43
_llseek(3, 0, [16384], SEEK_CUR) = 0
close(3) = 0
[snip]
_llseek(32, 0, [122880], SEEK_CUR) = 0
close(32) = 0
_llseek(33, 0, [8192], SEEK_CUR) = 0
close(33) = 0
_llseek(34, 0, [32768], SEEK_CUR) = 0
close(34) = 0
stat64("/pgtest/pgfuncs", 0xbfec3820) = -1 ENOENT (No such file or
directory)
stat64("/pgtest/pgfuncs.so", {st_mode=S_IFREG|0755, st_size=4490, ...}) = 0
stat64("/pgtest/pgfuncs.so", {st_mode=S_IFREG|0755, st_size=4490, ...}) = 0
--- SIGSEGV (Segmentation fault) @ 0 (0) ---
detailed steps to create the problem follow:
1. Create the C function
// pgfuncs.c
#include "postgres.h"
#include "fmgr.h"
#ifdef PG_MODULE_MAGIC
PG_MODULE_MAGIC;
#endif
PG_FUNCTION_INFO_V1(addone);
Datum addone(PG_FUNCTION_ARGS)
{
PG_RETURN_INT32(PG_GETARG_INT32(0) + 1);
}
// end pgfuncs.c
2. compile it
PG_SERVER_INC=/usr/local/pgsql/include/server
gcc -fpic -shared -I $PG_SERVER_INC -o /pgtest/pgfuncs.so pgfuncs.c
3. create the addone func (using a fresh psql session)
CREATE OR REPLACE FUNCTION addone(INTEGER) RETURNS INTEGER
AS '/pgtest/pgfuncs', 'addone' LANGUAGE C STRICT;
4. Execute addone, which will load pgfuncs.so
funcy=# select addone(1);
addone
--------
2
(1 row)
5. Try to reload the library (this works)
funcy=# LOAD '/pgtest/pgfuncs';
LOAD
6. Recomplie pgfuncs.so
Follow the same steps that are outlined in Step 2.
7. Issue a LOAD 'library' command
funcy=# LOAD '/pgtest/pgfuncs';
server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
!>
merlin
