Bug#318317: libc6: Numerous (49) memory leaks in gethostbyname, as reported by mudflap

2005-07-14 Thread Vesselin Peev
Package: libc6 Version: 2.3.2.ds1-22 Severity: normal How to reproduce: Create a file main.cpp / main.c with the following contents: #include int main() { gethostbyname("www.google.com"); return 0; } Then execute the following: g++-4.0 -fmudflap (the filename you created above

Bug#318317: libc6: Numerous (49) memory leaks in gethostbyname, as reported by mudflap

2005-07-14 Thread Vesselin Peev
This is not a problem, unless this number grows with each gethostbyname invocation. The underlying programming pattern which causes this is quite common and perfectly harmless (if you get the threading issues right, of coruse). Just tested it in a loop, the leaks stay constant. If you are sayin

Bug#318317: libc6: Numerous (49) memory leaks in gethostbyname, as reported by mudflap

2005-07-15 Thread Vesselin Peev
Jakub Jelinek from Red Hat said the following: "glibc doesn't free memory unnecessarily on program exit, only when using memory leak checking tools like mtrace or valgrind it will free all its internal buffers." I know the problem is not present with valgrind on Debian, too, so the above then h

Bug#318317: libc6: Numerous (49) memory leaks in gethostbyname, as reported by mudflap

2005-07-15 Thread Vesselin Peev
Very simple: gethostbyname() returns a "struct hostent *" for which the C library has to allocate some internal memory. However, POSIX/SUS/etc. does not define any API to tell the C library that the returned pointer is no longer needed, so the allocated memory cannot be freed by the C library unti

Bug#318317: libc6: Numerous (49) memory leaks in gethostbyname, as reported by mudflap

2005-07-15 Thread Vesselin Peev
Well, I know nothing about mudflap, but valgrind calls __libc_freeres() at program termination to avoid internal data allocated by glibc being reported as leaks. Thanks for mentioning this, Gabor! I searched for more info about it, and found it mentioned in the Valgrind FAQ, and also in the lib