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libsysprof-analyze: sanitize address ranges

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That way we are clamped to what the mapping actually provides. This only
seems to get messed up with glibc, but not clear why and it's barely off
so perhaps it has some special mapping tricks it does.

I still notice some non-reproducible runs, but that appears to be related
to duplicate address mapping entries for [stack] which we need to clear
up by removing the duplicate (short) entry.
This commit is contained in:
Christian Hergert
2023-05-22 20:06:12 -07:00
parent 5cc55117c3
commit e38eae7aa7
1 changed files with 22 additions and 6 deletions
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28
src/libsysprof-analyze/sysprof-elf-symbolizer.c
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@ -54,7 +54,8 @@ sysprof_elf_symbolizer_symbolize (SysprofSymbolizer *symbolizer,
g_autofree char *name = NULL;
const char *path;
const char *build_id;
guint64 start_address;
guint64 map_begin;
guint64 map_end;
guint64 relative_address;
guint64 begin_address;
guint64 end_address;
@ -76,12 +77,18 @@ sysprof_elf_symbolizer_symbolize (SysprofSymbolizer *symbolizer,
if (!(map = sysprof_address_layout_lookup (process_info->address_layout, address)))
return NULL;
map_begin = sysprof_document_mmap_get_start_address (map);
map_end = sysprof_document_mmap_get_end_address (map);
g_assert (address >= map_begin);
g_assert (address < map_end);
file_offset = sysprof_document_mmap_get_file_offset (map);
relative_address = file_offset + (address - map_begin);
path = sysprof_document_mmap_get_file (map);
build_id = sysprof_document_mmap_get_build_id (map);
file_inode = sysprof_document_mmap_get_file_inode (map);
file_offset = sysprof_document_mmap_get_file_offset (map);
start_address = sysprof_document_mmap_get_start_address (map);
relative_address = file_offset + (address - start_address);
/* See if we can load an ELF at the path . It will be translated from the
* mount namespace into something hopefully we can access.
@ -103,11 +110,19 @@ sysprof_elf_symbolizer_symbolize (SysprofSymbolizer *symbolizer,
&end_address)))
goto fallback;
/* Sanitize address ranges if we have to. Sometimes that can happen
* for us, but it seems to be limited to glibc.
*/
begin_address = CLAMP (begin_address, file_offset, file_offset + (map_end - map_begin));
end_address = CLAMP (end_address, file_offset, file_offset + (map_end - map_begin));
if (end_address == begin_address)
end_address++;
return _sysprof_symbol_new (sysprof_strings_get (strings, name),
sysprof_strings_get (strings, sysprof_elf_get_nick (elf)),
sysprof_strings_get (strings, path),
start_address + (begin_address - file_offset),
start_address + (end_address - file_offset));
map_begin + (begin_address - file_offset),
map_begin + (end_address - file_offset));
fallback:
/* Fallback, we failed to locate the symbol within a file we can
@ -119,6 +134,7 @@ fallback:
relative_address);
begin_address = address;
end_address = address + 1;
return _sysprof_symbol_new (sysprof_strings_get (strings, name),
NULL, NULL, begin_address, end_address);
}