This is the mail archive of the
gdb-patches@sources.redhat.com
mailing list for the GDB project.
[RFA] breakpoint.c: Avoid double freeing in breakpoint_re_set_one
- From: Paul Hilfinger <hilfingr at gnat dot com>
- To: gdb-patches at sources dot redhat dot com
- Date: Fri, 9 Jan 2004 03:22:13 -0500 (EST)
- Subject: [RFA] breakpoint.c: Avoid double freeing in breakpoint_re_set_one
Here's a subtle little number discovered while looking at something entirely
different. breakpoint_re_set_one is called from within a catch handler.
If the calls to parse_exp_1 for the condition error out due to, say,
the presence of a symbol that has become undefined, a cond field may
get freed twice. Tested on Linux without regression. OK to commit?
2004-01-09 Paul N. Hilfinger <nile@gnat.com>
* breakpoint.c: Update copyright to include 2004.
(breakpoint_re_set_one): Set b->cond to NULL after freeing
so that error during re-parsing of breakpoint condition
does not eventually lead to re-freeing of storage.
Index: current-public.39/gdb/breakpoint.c
--- current-public.39/gdb/breakpoint.c Sun, 04 Jan 2004 17:51:24 -0800 hilfingr (GdbPub/g/23_breakpoint 1.1.1.7.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1 644)
+++ current-public.39(w)/gdb/breakpoint.c Fri, 09 Jan 2004 00:16:01 -0800 hilfingr (GdbPub/g/23_breakpoint 1.1.1.7.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1 644)
@@ -1,8 +1,8 @@
/* Everything about breakpoints, for GDB.
Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
- 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003 Free Software
- Foundation, Inc.
+ 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
+ Free Software Foundation, Inc.
This file is part of GDB.
@@ -7009,6 +7009,9 @@ breakpoint_re_set_one (void *bint)
s = b->cond_string;
if (b->cond)
xfree (b->cond);
+ /* Set b->cond to NULL to avoid re-freeing later if error
+ during parse_exp_1. */
+ b->cond = NULL;
b->cond = parse_exp_1 (&s, block_for_pc (sals.sals[i].pc), 0);
}
@@ -7092,6 +7095,9 @@ breakpoint_re_set_one (void *bint)
s = b->cond_string;
if (b->cond)
xfree (b->cond);
+ /* Set b->cond to NULL to avoid re-freeing later if error
+ during parse_exp_1. */
+ b->cond = NULL;
b->cond = parse_exp_1 (&s, (struct block *) 0, 0);
}
if (breakpoint_enabled (b))