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Multiple apparent leaks in dwarf2.c
- From: John Levon <levon at movementarian dot org>
- To: binutils at sources dot redhat dot com
- Cc: Philippe Elie <phil dot el at wanadoo dot fr>
- Date: Thu, 21 Apr 2005 07:03:40 +0100
- Subject: Multiple apparent leaks in dwarf2.c
With the following:
#include <bfd.h>
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char *argv[])
{
bfd * b;
long f;
void *syms;
size_t size;
asymbol **as;
const char *file;
const char *func;
int line;
if (argc < 2) {
printf("usage: valbfd <file>\n");
exit(1);
}
if (!(b = bfd_openr(argv[1], NULL))) {
printf("failed to open %s.\n", argv[1]);
exit(1);
}
if (!bfd_check_format_matches(b, bfd_object, NULL)) {
printf("no match.\n");
exit(1);
}
if (!(bfd_get_file_flags(b) & HAS_SYMS)) {
printf("no syms.\n");
exit(1);
}
size = bfd_get_symtab_upper_bound(b);
syms = malloc(size);
as = syms;
bfd_canonicalize_symtab(b, syms);
bfd_find_nearest_line(b, (*as)->section, as, 4000000, &file, &func, &line);
bfd_close(b);
free(syms);
}
valgrind tells us:
==15031== 18577 bytes in 1 blocks are definitely lost in loss record 1 of 4
==15031== at 0x1B903534: malloc (vg_replace_malloc.c:130)
==15031== by 0x8049790: bfd_malloc (libbfd.c:152)
==15031== by 0x808CE7E: bfd_simple_get_relocated_section_contents (simple.c:150)
==15031== by 0x808B75F: read_abbrevs (dwarf2.c:447)
==15031== by 0x808C77A: parse_comp_unit (dwarf2.c:1483)
==15031== by 0x808CB76: _bfd_dwarf2_find_nearest_line (dwarf2.c:1832)
==15031== by 0x805D324: _bfd_elf_find_nearest_line (elf.c:6111)
==15031== by 0x8049281: main (valbfd.c:40)
==15031==
==15031==
==15031== 43184 bytes in 619 blocks are definitely lost in loss record 2 of 4
==15031== at 0x1B903F5A: realloc (vg_replace_malloc.c:196)
==15031== by 0x80497D0: bfd_realloc (libbfd.c:175)
==15031== by 0x808B679: read_abbrevs (dwarf2.c:495)
==15031== by 0x808C77A: parse_comp_unit (dwarf2.c:1483)
==15031== by 0x808CB76: _bfd_dwarf2_find_nearest_line (dwarf2.c:1832)
==15031== by 0x805D324: _bfd_elf_find_nearest_line (elf.c:6111)
==15031== by 0x8049281: main (valbfd.c:40)
==15031==
==15031==
==15031== 48831 (23816 direct, 25015 indirect) bytes in 742 blocks are definitely lost in loss record 3 of 4
==15031== at 0x1B903534: malloc (vg_replace_malloc.c:130)
==15031== by 0x8049800: bfd_realloc (libbfd.c:173)
==15031== by 0x808B679: read_abbrevs (dwarf2.c:495)
==15031== by 0x808C77A: parse_comp_unit (dwarf2.c:1483)
==15031== by 0x808CB76: _bfd_dwarf2_find_nearest_line (dwarf2.c:1832)
==15031== by 0x805D324: _bfd_elf_find_nearest_line (elf.c:6111)
==15031== by 0x8049281: main (valbfd.c:40)
These appear to indeed be valid leaks: the code is using the
non-objalloc'd bfd_realloc/bfd_malloc routines, but there's nothing to
clear up the debug info stash that I can see (binutils 2.15).
Using an earlier binutils, there was also leaks in decode_line_info()
centering around concat_filename(). These appear to have been mostly
fixed, though code inspection shows some obvious error path leaks:
1058 char * filename = table->num_files ? concat_filename (table, 1) : NULL;
...
1142 bfd_set_error (bfd_error_bad_value);
1143 return 0;
...
1125 if (! table->files)
1126 return 0;
...
1208 if (filename)
1209 free (filename);
It's the other ones that are the big concern though: this is leaking 4Mb with
our application. Any chance of these getting fixed? I couldn't see a
particular reason that bfd_simple_get_relocated_section_contents()
wasn't allocating from abfd->memory, but I don't know what's best for
the realloc ones. Do we need some gunk in _bfd_elf_close_and_cleanup() ?
(I haven't looked hard at the source, so it's possible I've got things
wrong).
cheers,
john