Attached (debugtest.c) is a small program that reliably crashes/corrupts memory under RedHat 9 when using dynamic linking...static linking works fine.
Based on the following tests/symptoms this looks like a bug in the new pthread implementation.
Below is the comment at the top of the test program with the results of the various tests. If anyone knows a work around for this, I would greatly appreciate it.
/* this proggy shows the corruption under rh9 using shared libs...with rrdtool-1.0.42 (http://www.rrdtool.org)
You can compile this program 3 ways: static, dynamically linked to librrd.so and dynamically loaded via dlopen(). Errors occur with either of the dynamicly linked versions.
Specifically...
when setting MALLOC_CHECK_=1 and runnng dynamic/dlopen you will see 'free(): invalid pointer' warnings
when UNsetting MALLOC_CHECK_ and running valgrind (http://valgrind.kde.org/), all versions work
when UNsetting MALLOC_CHECK_ and runnng dynamic/dlopen you will see these hang, strace report hanging on a futex:
open("txbytes.rrd", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3
fstat64(3, {st_mode=S_IFREG|0664, st_size=0, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40017000
write(3, "RRD\0000001\0\0\0\0/%\300\307C+\37[\1\0\0\0\2\0\0\0\n\0"..., 1260) = 1260
close(3) = 0
munmap(0x40017000, 4096) = 0
time(NULL) = 1068744414
open("txbytes.rrd", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3
fstat64(3, {st_mode=S_IFREG|0664, st_size=0, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40017000
futex(0x8049cc0, FUTEX_WAIT, -127, NULL <unfinished ...>running a DIFFERENT program (the one that started me on this bug hunt, aware (http://www.elegant-software.com/software/aware),which uses pthreads) under valgrind I see:
==24437== pthread_mutex_lock/trylock: mutex is invalid ==24437== at 0x40227B10: __pthread_mutex_lock (vg_libpthread.c:951) ==24437== by 0x4022B287: _IO_flockfile (vg_libpthread.c:3130) ==24437== by 0x402D0F92: _IO_un_link_internal (in /lib/libc-2.3.2.so) ==24437== by 0x402CD8E8: _IO_fclose@xxxxxxxxx (in /lib/libc-2.3.2.so) ==24437==
running the above DIFFERENT program WITHOUT valgrind gets a segfault when executing rrd_create() via dlopen() linking.
*/
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <ctype.h> #include <dlfcn.h> #include "rrd.h" /* this proggy shows the corruption under rh9 using shared libs...with rrdtool-1.0.42 (http://www.rrdtool.org) You can compile this program 3 ways: static, dynamically linked to librrd.so and dynamically loaded via dlopen(). Errors occur with either of the dynamicly linked versions. Specifically... when setting MALLOC_CHECK_=1 and runnng dynamic/dlopen you will see 'free(): invalid pointer' warnings when UNsetting MALLOC_CHECK_ and running valgrind (http://valgrind.kde.org/), all versions work when UNsetting MALLOC_CHECK_ and runnng dynamic/dlopen you will see these hang, straces report hanging on a futex: open("txbytes.rrd", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3 fstat64(3, {st_mode=S_IFREG|0664, st_size=0, ...}) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40017000 write(3, "RRD\0000001\0\0\0\0/%\300\307C+\37[\1\0\0\0\2\0\0\0\n\0"..., 1260) = 1260 close(3) = 0 munmap(0x40017000, 4096) = 0 time(NULL) = 1068744414 open("txbytes.rrd", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3 fstat64(3, {st_mode=S_IFREG|0664, st_size=0, ...}) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40017000 futex(0x8049cc0, FUTEX_WAIT, -127, NULL <unfinished ...> running a DIFFERENT program (the one that started me on this bug hunt, aware (http://www.elegant-software.com/software/aware),which uses pthreads) under valgrind I see: ==24437== pthread_mutex_lock/trylock: mutex is invalid ==24437== at 0x40227B10: __pthread_mutex_lock (vg_libpthread.c:951) ==24437== by 0x4022B287: _IO_flockfile (vg_libpthread.c:3130) ==24437== by 0x402D0F92: _IO_un_link_internal (in /lib/libc-2.3.2.so) ==24437== by 0x402CD8E8: _IO_fclose@xxxxxxxxx (in /lib/libc-2.3.2.so) ==24437== running the above DIFFERENT program WITHOUT valgrind gets a segfault when executing rrd_create() via dlopen() linking. */ /* first convert librrd.a to a .so: ar x librrd.a ld -shared -soname=librrd.so -o ./librrd.so *.o */ /* static compile: gcc -static -O2 -g -I/usr/local/rrdtool-1.0.42/include debugtest.c -o debugtest -L/usr/local/rrdtool-1.0.42/lib -lrrd */ // NO CORRUPTION! /* dynamic compile: gcc -O2 -g -I/usr/local/rrdtool-1.0.42/include debugtest.c -o debugtest -L/usr/local/rrdtool-1.0.42/lib -lrrd -lm */ // CORRUPTION! /* ldopen compile: gcc -DLDOPEN -O2 -g -rdynamic -I/usr/local/rrdtool-1.0.42/include debugtest.c -o debugtest -ldl -L/usr/local/rrdtool-1.0.42/lib -lrrd -lm */ // CORRUPTION! /* before running, export MALLOC_CHECK_=1 */ /* before running, export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/rrdtool-1.0.42/lib */ /* to run, do gdb debugtest */ void main() { char *argv[] = { "create", "txbytes.rrd", "-s", "10", "DS:bytes:GAUGE:30:U:U", "RRA:AVERAGE:0.5:1:6", "RRA:AVERAGE:0.5:6:60" }; int counter=100, argc = 7; #ifndef LDOPEN while (counter--) rrd_create(argc, argv); #else { void *sohandle = dlopen("librrd.so", RTLD_NOW|RTLD_GLOBAL); int (*rrdcreate_function)(int, char **); if (sohandle == NULL) { perror("rrd.so"); exit(-1); } /* lookup constructor */ rrdcreate_function = dlsym(sohandle, "rrd_create"); if (rrdcreate_function == NULL) { fprintf(stderr, "Unable to find rrd_create\n"); exit(-1); }/* end if */ while (counter--) (*rrdcreate_function)(argc,argv); } #endif }
