diff --git a/FAQ.txt b/FAQ.txt index 625c55cb4..523f03885 100644 --- a/FAQ.txt +++ b/FAQ.txt @@ -200,6 +200,11 @@ If they're not detailed enough, make sure you are compiling with -g to add debug information. And don't strip symbol tables (programs should be unstripped unless you run 'strip' on them; some libraries ship stripped). +Also, for leak reports involving shared objects, if the shared object is +unloaded before the program terminates, Valgrind will discard the debug +information and the error message will be full of "???" entries. The +workaround here is to avoid calling dlclose() on these shared objects. + Also, -fomit-frame-pointer and -fstack-check can make stack traces worse. Some example sub-traces: @@ -231,6 +236,15 @@ Some example sub-traces: by 0x42015703: __libc_start_main (in /lib/tls/libc-2.3.2.so) by 0x80482CC: ??? (start.S:81) + A leak error message involving an unloaded shared object: + + 84 bytes in 1 blocks are possibly lost in loss record 488 of 713 + at 0x1B9036DA: operator new(unsigned) (vg_replace_malloc.c:132) + by 0x1DB63EEB: ??? + by 0x1DB4B800: ??? + by 0x1D65E007: ??? + by 0x8049EE6: main (main.cpp:24) + ----------------------------------------------------------------- 5. Memcheck doesn't find my bug ----------------------------------------------------------------- diff --git a/docs/xml/FAQ.xml b/docs/xml/FAQ.xml index fed9275c6..d4e1d6c88 100644 --- a/docs/xml/FAQ.xml +++ b/docs/xml/FAQ.xml @@ -284,6 +284,13 @@ unless you run 'strip' on them; some libraries ship stripped). + Also, for leak reports involving shared objects, if the shared + object is unloaded before the program terminates, Valgrind will discard + the debug information and the error message will be full of + ??? entries. The workaround here is to avoid calling + dlclose() on these shared objects. + + Also, -fomit-frame-pointer and -fstack-check can make stack traces worse. @@ -321,6 +328,17 @@ Invalid write of size 1 by 0x80482CC: ??? (start.S:81) + A leak error message involving an unloaded shared object: + + +84 bytes in 1 blocks are possibly lost in loss record 488 of 713 + at 0x1B9036DA: operator new(unsigned) (vg_replace_malloc.c:132) + by 0x1DB63EEB: ??? + by 0x1DB4B800: ??? + by 0x1D65E007: ??? + by 0x8049EE6: main (main.cpp:24) + +