[Valgrind-users] gcc -pg & valgrind errors

[Stijn v. D. <st...@di...>]

   Hi,

recently I profiled a program with gprof, so compiled the sources
with -pg (and -g as well by the way, I am assuming those mix without
problems).

At that point valgrind began to emit strange errors; stuff like
[ for a single-statement program importing a thoroughly tested library. ]

[gershwin hobo mcl/shtest > valgrind --num-callers=12 ./tst
==1161== Memcheck, a.k.a. Valgrind, a memory error detector for
x86-linux.
==1161== Copyright (C) 2002, and GNU GPL'd, by Julian Seward.
==1161== Using valgrind-1.9.6, a program instrumentation system for
x86-linux.
==1161== Copyright (C) 2000-2002, and GNU GPL'd, by Julian Seward.
==1161== Estimated CPU clock rate is 449 MHz
==1161== For more details, rerun with: -v
==1161== 
==1161== Conditional jump or move depends on uninitialised value(s)
==1161==    at 0x4032A049: (within /lib/libc-2.2.5.so)
==1161==    by 0x4017E44F: (within
/home/hobo/local/lib/valgrind/valgrind.so)
==1161==    by 0x403297CD: moncontrol (in /lib/libc-2.2.5.so)
==1161==    by 0x40329EB5: _mcleanup (in /lib/libc-2.2.5.so)
==1161==    by 0x40283E52: exit (in /lib/libc-2.2.5.so)
==1161==    by 0x40271154: __libc_start_main (in /lib/libc-2.2.5.so)
==1161==    by 0x80487D0: (within
/home/hobo/cvs/topaz/micans/mcl/shtest/tst)
==1161== 
==1161== Invalid free() / delete / delete[]
==1161==    at 0x40167B8B: free (vg_clientfuncs.c:185)
==1161==    by 0x40329ED8: _mcleanup (in /lib/libc-2.2.5.so)
==1161==    by 0x40283E52: exit (in /lib/libc-2.2.5.so)
==1161==    by 0x40271154: __libc_start_main (in /lib/libc-2.2.5.so)
==1161==    by 0x80487D0: (within
/home/hobo/cvs/topaz/micans/mcl/shtest/tst)
==1161==    Address 0x40375024 is not stack'd, malloc'd or free'd
==1161== 
==1161== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 0 from 0)
==1161== malloc/free: in use at exit: 233 bytes in 3 blocks.
==1161== malloc/free: 4 allocs, 2 frees, 234 bytes allocated.
==1161== For a detailed leak analysis,  rerun with: --leak-check=yes
==1161== For counts of detected errors, rerun with: -v

recompiling with '-g -Wall -pedantic -ansi -O2' and without -pg
make the errors go away.

Is it obvious that I should not use -pg, or should valgrind do
just fine with -pg and must I further investigate this stuff (and
post a minimal example) ? - or does -pg not mix with some of the
other gcc options I am using?

I checked the web docs, and failed in finding an answer there.

regards,
Stijn