Mismatched free() / delete / delete[] -- false positives

*         Valgrind-3.13.0

*         CentOS release 6.5 (Final)

*         g++ (GCC) 5.3.0

*         no usage of tcmalloc
I checked by
cat /proc/<PID>/maps |sed -e 's/[a-zA-Z0-9_:-]*[ \t][ \t]*//g'|sort -u|xargs nm -A|grep '\<free\>'|grep -v '\<U\>'
output was
/lib64/ld-2.12.so:0000003bfba16090 W free
/lib64/libc-2.12.so:0000003bfc27b520 T free
/path/executable:000000000f9f3c50 W free

*         positives for both directions

o   free used for memory allocated with new

o   delete used for memory allocated with malloc

1)
==11679== Mismatched free() / delete / delete []
==11679==    at 0x127ECAFE: free (vg_replace_malloc.c:530)
==11679==    by 0x1CC871A1: void std::_Destroy<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*) (stl_construct.h:93)
==11679==    by 0x1CC82295: void std::_Destroy_aux<false>::__destroy<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*>(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*) (stl_construct.h:103)
...
==11679==  Address 0x2633aeb0 is 0 bytes inside a block of size 155 alloc'd
==11679==    at 0x127EDBE7: operator new(unsigned long) (vg_replace_malloc.c:334)
==11679==    by 0x54B81C3: void std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_construct<char*>(char*, char*, std::forwar
d_iterator_tag) (basic_string.tcc:223)

2)
==11679== Mismatched free() / delete / delete []
==11679==    at 0x127EC64E: operator delete(void*) (vg_replace_malloc.c:576)
==11679==    by 0x8172EC3: __gnu_cxx::new_allocator<Sdi::StateVar const*>::deallocate(Sdi::StateVar const**, unsigned long) (new_allocator.h:110)
==11679==    by 0x8172767: std::allocator_traits<std::allocator<Sdi::StateVar const*> >::deallocate(std::allocator<Sdi::StateVar const*>&, Sdi::StateVar const**, unsigned long) (alloc_traits.h:386)
...
==11679==  Address 0x2a5e08b0 is 0 bytes inside a block of size 32 alloc'd
==11679==    at 0x127ED104: malloc (vg_replace_malloc.c:299)
==11679==    by 0x206F33E7: operator new(unsigned long) (new_op.cc:50)
==11679==    by 0x1CCE9829: __gnu_cxx::new_allocator<Sdi::StateVar const*>::allocate(unsigned long, void const*) (new_allocator.h:104)


There are only a 7 of the 1) messages and 3 of the 2) despite there are many more such allocations.
As you can see, both places are inside STL and thus are likely to be correct.
I think vg_replace_malloc.c is coming from valgrind, isn't it?


Peter

Mogan : Hey Bruno. What are you? A 65?
Bruno : Model 63. Deluxe.
Kelp : 63? Talk about ancient.
Bruno : Your sister didn't seem to mind.

_______________________________________________
Valgrind-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/valgrind-users