linux-kernel - [PATCH 3/6] perf symbols: Rebuild rbtree when adjusting symbols for kcore

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 12 Nov 2015 19:56:09 -0300
From:	Arnaldo Carvalho de Melo <acme@...nel.org>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	linux-kernel@...r.kernel.org,
	Adrian Hunter <adrian.hunter@...el.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
	Namhyung Kim <namhyung@...nel.org>,
	Zefan Li <lizefan@...wei.com>, pi3orama@....com,
	Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: [PATCH 3/6] perf symbols: Rebuild rbtree when adjusting symbols for kcore

From: Adrian Hunter <adrian.hunter@...el.com>

Normally symbols are read from the DSO and adjusted, if need be, so that
the symbol start matches the file offset in the DSO file (we want the
file offset because that is what we know from MMAP events). That is done
by dso__load_sym() which inserts the symbols *after* adjusting them.

In the case of kcore, the symbols have been read from kallsyms and the
symbol start is the memory address. The symbols have to be adjusted to
match the kcore file offsets. dso__split_kallsyms_for_kcore() does that,
but now the adjustment is being done *after* the symbols have been
inserted. It appears dso__split_kallsyms_for_kcore() was assuming that
changing the symbol start would not change the order in the rbtree -
which is, of course, not guaranteed.

Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
Tested-by: Wang Nan <wangnan0@...wei.com>
Cc: Jiri Olsa <jolsa@...nel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Zefan Li <lizefan@...wei.com>
Cc: pi3orama@....com
Link: http://lkml.kernel.org/r/563CB241.2090701@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/util/symbol.c | 30 ++++++++++++++----------------
 1 file changed, 14 insertions(+), 16 deletions(-)

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;
 }
 
 /*
-- 
2.1.0

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/