[PATCH v2 25/26] perf srcline: Change free_srcline to zfree_srcline

[Ian Rogers]

Make use after free more unlikely.

Signed-off-by: Ian Rogers <irogers at google.com>
---
 tools/perf/builtin-diff.c    |  4 ++--
 tools/perf/util/annotate.c   |  2 +-
 tools/perf/util/block-info.c |  4 ++--
 tools/perf/util/hist.c       |  6 +++---
 tools/perf/util/map.c        |  2 +-
 tools/perf/util/srcline.c    | 15 ++++++++++-----
 tools/perf/util/srcline.h    |  2 +-
 7 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index ca39657ee407..eec89567ae48 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -1387,8 +1387,8 @@ static int cycles_printf(struct hist_entry *he, struct hist_entry *pair,
 			  bi->start, bi->end, block_he->diff.cycles);
 	}
 
-	free_srcline(start_line);
-	free_srcline(end_line);
+	zfree_srcline(&start_line);
+	zfree_srcline(&end_line);
 
 	return scnprintf(hpp->buf, hpp->size, "%*s", width, buf);
 }
diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index fc5f44535ebe..58fc5fa00ecd 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -1196,7 +1196,7 @@ static void annotation_line__init(struct annotation_line *al,
 
 static void annotation_line__exit(struct annotation_line *al)
 {
-	free_srcline(al->path);
+	zfree_srcline(&al->path);
 	zfree(&al->line);
 }
 
diff --git a/tools/perf/util/block-info.c b/tools/perf/util/block-info.c
index 16a7b4adcf18..08279b1b65e5 100644
--- a/tools/perf/util/block-info.c
+++ b/tools/perf/util/block-info.c
@@ -305,8 +305,8 @@ static int block_range_entry(struct perf_hpp_fmt *fmt, struct perf_hpp *hpp,
 			  bi->start, bi->end);
 	}
 
-	free_srcline(start_line);
-	free_srcline(end_line);
+	zfree_srcline(&start_line);
+	zfree_srcline(&end_line);
 
 	return scnprintf(hpp->buf, hpp->size, "%*s", block_fmt->width, buf);
 }
diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index 4004c0915e4f..77cb2cc83bb9 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -1317,8 +1317,8 @@ void hist_entry__delete(struct hist_entry *he)
 	if (he->branch_info) {
 		map__zput(he->branch_info->from.ms.map);
 		map__zput(he->branch_info->to.ms.map);
-		free_srcline(he->branch_info->srcline_from);
-		free_srcline(he->branch_info->srcline_to);
+		zfree_srcline(&he->branch_info->srcline_from);
+		zfree_srcline(&he->branch_info->srcline_to);
 		zfree(&he->branch_info);
 	}
 
@@ -1336,7 +1336,7 @@ void hist_entry__delete(struct hist_entry *he)
 
 	zfree(&he->res_samples);
 	zfree(&he->stat_acc);
-	free_srcline(he->srcline);
+	zfree_srcline(&he->srcline);
 	if (he->srcfile && he->srcfile[0])
 		zfree(&he->srcfile);
 	free_callchain(he->callchain);
diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index ae1d54d4880a..c77e2fce6a37 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -498,7 +498,7 @@ int map__fprintf_srcline(struct map *map, u64 addr, const char *prefix,
 		char *srcline = map__srcline(map, addr, NULL);
 		if (strncmp(srcline, SRCLINE_UNKNOWN, strlen(SRCLINE_UNKNOWN)) != 0)
 			ret = fprintf(fp, "%s%s", prefix, srcline);
-		free_srcline(srcline);
+		zfree_srcline(&srcline);
 	}
 	return ret;
 }
diff --git a/tools/perf/util/srcline.c b/tools/perf/util/srcline.c
index cfca03abd6f8..b8e596528d7e 100644
--- a/tools/perf/util/srcline.c
+++ b/tools/perf/util/srcline.c
@@ -804,10 +804,15 @@ char *get_srcline_split(struct dso *dso, u64 addr, unsigned *line)
 	return NULL;
 }
 
-void free_srcline(char *srcline)
+void zfree_srcline(char **srcline)
 {
-	if (srcline && strcmp(srcline, SRCLINE_UNKNOWN) != 0)
-		free(srcline);
+	if (*srcline == NULL)
+		return;
+
+	if (strcmp(*srcline, SRCLINE_UNKNOWN))
+		free(*srcline);
+
+	*srcline = NULL;
 }
 
 char *get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
@@ -880,7 +885,7 @@ void srcline__tree_delete(struct rb_root_cached *tree)
 		pos = rb_entry(next, struct srcline_node, rb_node);
 		next = rb_next(&pos->rb_node);
 		rb_erase_cached(&pos->rb_node, tree);
-		free_srcline(pos->srcline);
+		zfree_srcline(&pos->srcline);
 		zfree(&pos);
 	}
 }
@@ -903,7 +908,7 @@ void inline_node__delete(struct inline_node *node)
 
 	list_for_each_entry_safe(ilist, tmp, &node->val, list) {
 		list_del_init(&ilist->list);
-		free_srcline(ilist->srcline);
+		zfree_srcline(&ilist->srcline);
 		/* only the inlined symbols are owned by the list */
 		if (ilist->symbol && ilist->symbol->inlined)
 			symbol__delete(ilist->symbol);
diff --git a/tools/perf/util/srcline.h b/tools/perf/util/srcline.h
index b11a0aaaa676..a15c7db9058e 100644
--- a/tools/perf/util/srcline.h
+++ b/tools/perf/util/srcline.h
@@ -15,7 +15,7 @@ char *get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
 char *__get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
 		  bool show_sym, bool show_addr, bool unwind_inlines,
 		  u64 ip);
-void free_srcline(char *srcline);
+void zfree_srcline(char **srcline);
 char *get_srcline_split(struct dso *dso, u64 addr, unsigned *line);
 
 /* insert the srcline into the DSO, which will take ownership */
-- 
2.41.0.162.gfafddb0af9-goog