Fix memory leak during regular expression execution.

tglsfdc · tglsfdc · commit ea8c7e9054ab · 2014-03-19T11:09:24.000-04:00
For a regex containing backrefs, pg_regexec() might fail to free all the sub-DFAs that were created during execution, resulting in a permanent (session lifespan) memory leak. Problem was introduced by me in commit 5873594. Per report from Sandro Santilli; diagnosis by Greg Stark.
diff --git a/src/backend/regex/regexec.c b/src/backend/regex/regexec.c
@@ -259,6 +259,7 @@ pg_regexec(regex_t *re,
 	/* clean up */
 	if (v->pmatch != pmatch && v->pmatch != mat)
 		FREE(v->pmatch);
+	n = (size_t) v->g->ntree;
 	for (i = 0; i < n; i++)
 	{
 		if (v->subdfas[i] != NULL)

Original file line number	Diff line number	Diff line change
`@@ -259,6 +259,7 @@ pg_regexec(regex_t *re,`
`259`	`259`	`/* clean up */`
`260`	`260`	`if (v->pmatch != pmatch && v->pmatch != mat)`
`261`	`261`	`FREE(v->pmatch);`
	`262`	`+ n = (size_t) v->g->ntree;`
`262`	`263`	`for (i = 0; i < n; i++)`
`263`	`264`	`{`
`264`	`265`	`if (v->subdfas[i] != NULL)`