solve memory problems checked by valgrind

Question

I have a problem, with valgrind; I dont know why when I check my program developped in C with valgrind, it couldn't display functions names (it display "???") where it found problems but this problems is not for all errors that it detects

==9803== ERROR SUMMARY: 24 errors from 6 contexts (suppressed: 0 from 0)
==9803== 
==9803== 1 errors in context 1 of 6:
==9803== Conditional jump or move depends on uninitialised value(s)
==9803==    at 0x40F7EC6: ???
==9803== 
==9803== 1 errors in context 2 of 6:
==9803== Conditional jump or move depends on uninitialised value(s)
==9803==    at 0x40F86F8: ???
==9803== 
==9803== 1 errors in context 3 of 6:
==9803== Conditional jump or move depends on uninitialised value(s)
==9803==    at 0x40F8166: ???
==9803== 
==9803== 1 errors in context 4 of 6:
==9803== Conditional jump or move depends on uninitialised value(s)
==9803==    at 0x40F805E: ???
==9803==

Have you a solution for displaying functions names with valgrind?

Thanks in advance

Answer 1

Presumably these errors are occurring in libraries for which you have no debug symbols. It's easy to confirm: just do look at /proc/pidof my-binary/maps while the application is running.

08048000-08052000 r-xp 00000000 fe:00 42546         /bin/cat
08052000-08053000 rw-p 0000a000 fe:00 42546         /bin/cat
097fb000-0981c000 rw-p 00000000 00:00 0             [heap]
f73bc000-f75ac000 r--p 00000000 fe:02 281727        /usr/lib/locale/locale-archive
f75ac000-f75ad000 rw-p 00000000 00:00 0 
f75ad000-f76ed000 r-xp 00000000 fe:00 18416         /lib/i686/cmov/libc-2.11.2.so
f76ed000-f76ef000 r--p 0013f000 fe:00 18416         /lib/i686/cmov/libc-2.11.2.so
f76ef000-f76f0000 rw-p 00141000 fe:00 18416         /lib/i686/cmov/libc-2.11.2.so
f76f0000-f76f3000 rw-p 00000000 00:00 0 
f7705000-f7707000 rw-p 00000000 00:00 0 
f7707000-f7708000 r-xp 00000000 00:00 0             [vdso]
f7708000-f7723000 r-xp 00000000 fe:00 19087         /lib/ld-2.11.2.so
f7723000-f7724000 r--p 0001a000 fe:00 19087         /lib/ld-2.11.2.so
f7724000-f7725000 rw-p 0001b000 fe:00 19087         /lib/ld-2.11.2.so
ffb6e000-ffb83000 rw-p 00000000 00:00 0             

This clearly shows the addresses of the code sections (marked as r-xp) of each shared library. Just find the range matching the addresses you see and you'll at least know which library is responsible.