From 9d0cdc0eeaf8b0ca19bf04c5e18b00d965fcd0a8 Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Thu, 9 Sep 2004 01:58:35 +0000 Subject: Update. 2004-09-08 Ulrich Drepper * malloc/malloc.c (_int_free): Add inexpensive double free test. --- malloc/malloc.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'malloc') diff --git a/malloc/malloc.c b/malloc/malloc.c index 5636d5cfb0..4db40514d6 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -4201,6 +4201,13 @@ _int_free(mstate av, Void_t* mem) set_fastchunks(av); fb = &(av->fastbins[fastbin_index(size)]); + /* Another simple check: make sure the top of the bin is not the + record we are going to add (i.e., double free). */ + if (__builtin_expect (*fb == p, 0)) + { + malloc_printf_nc (check_action, "double free(%p)!\n", mem); + return; + } p->fd = *fb; *fb = p; } -- cgit v1.2.3