On 06/11/15 15:19, Arnaldo Carvalho de Melo wrote:
> Em Fri, Nov 06, 2015 at 09:46:12AM +0000, Wang Nan escreveu:
>> In dso__split_kallsyms_for_kcore(), current code adjusts symbol's
>> address but only reinsert it into rbtree if the symbol belongs to
>> another map. However, the expression for adjusting symbol (pos->start -=
>> curr_map->start - curr_map->pgoff) can change the relative order between
>> two symbols (even if the affected symbols are in different maps, in
>> kcore case they are possible to share one same dso), which damages the
>> rbtree.
>
> Right, some code does change the symbol values it gets from whatever
> symtab (kallsyms, ELF, JIT maps, etc) when it should instead use the per
> map data structure (struct map) and its ->{map,unmap}_ip, ->pgoff,
> ->reloc, members for that :-\
>
> I.e. 'struct dso' should be just what comes from the symtab, while
> 'struct map' should be about where that DSO is in memory.
>
> With that in mind, do you still think your fix is the correct one?
>
> Adrian?
The problem is when the order in memory (in kallsyms) is different
to the order on the dso (kcore).
I think to make it more general it needs to insert to a new tree.
e.g.
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index b4cc7662677e..09343a880c0b 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -654,19 +654,24 @@ static int dso__split_kallsyms_for_kcore(struct dso *dso,
struct map *map,
struct map_groups *kmaps = map__kmaps(map);
struct map *curr_map;
struct symbol *pos;
- int count = 0, moved = 0;
+ int count = 0;
+ struct rb_root old_root = dso->symbols[map->type];
struct rb_root *root = &dso->symbols[map->type];
struct rb_node *next = rb_first(root);
if (!kmaps)
return -1;
+ *root = RB_ROOT;
+
while (next) {
char *module;
pos = rb_entry(next, struct symbol, rb_node);
next = rb_next(&pos->rb_node);
+ rb_erase_init(&pos->rb_node, &old_root);
+
module = strchr(pos->name, '\t');
if (module)
*module = '\0';
@@ -674,28 +679,21 @@ static int dso__split_kallsyms_for_kcore(struct dso *dso,
struct map *map,
curr_map = map_groups__find(kmaps, map->type, pos->start);
if (!curr_map || (filter && filter(curr_map, pos))) {
- rb_erase_init(&pos->rb_node, root);
symbol__delete(pos);
- } else {
- pos->start -= curr_map->start - curr_map->pgoff;
- if (pos->end)
- pos->end -= curr_map->start - curr_map->pgoff;
- if (curr_map->dso != map->dso) {
- rb_erase_init(&pos->rb_node, root);
- symbols__insert(
- &curr_map->dso->symbols[curr_map->type],
- pos);
- ++moved;
- } else {
- ++count;
- }
+ continue;
}
+
+ pos->start -= curr_map->start - curr_map->pgoff;
+ if (pos->end)
+ pos->end -= curr_map->start - curr_map->pgoff;
+ symbols__insert(&curr_map->dso->symbols[curr_map->type], pos);
+ ++count;
}
/* Symbols have been adjusted */
dso->adjust_symbols = 1;
- return count + moved;
+ return count;
}
/*
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
