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authorJoern Engel <joern@logfs.org>2011-11-20 22:29:01 +0530
committerPrasad Joshi <prasadjoshi.linux@gmail.com>2012-01-28 11:24:21 +0530
commit934eed395d201bf0901ca0c0cc3703b18729d0ce (patch)
tree27847639b14a0fc16b850bd39c0ace939694d8f2
parent96150606e2fb82d242c9e4a414e4e922849f7bf7 (diff)
downloadlinux-934eed395d201bf0901ca0c0cc3703b18729d0ce.tar.gz
logfs: Prevent memory corruption
This is a bad one.  I wonder whether we were so far protected by
no_free_segments(sb) usually being smaller than LOGFS_NO_AREAS.

Found by Dan Carpenter <dan.carpenter@oracle.com> using smatch.

Signed-off-by: Joern Engel <joern@logfs.org>
Signed-off-by: Prasad Joshi <prasadjoshi.linux@gmail.com>
-rw-r--r--fs/logfs/gc.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/logfs/gc.c b/fs/logfs/gc.c
index caa4419285dc..d4efb061bdc5 100644
--- a/fs/logfs/gc.c
+++ b/fs/logfs/gc.c
@@ -367,7 +367,7 @@ static struct gc_candidate *get_candidate(struct super_block *sb)
 	int i, max_dist;
 	struct gc_candidate *cand = NULL, *this;
 
-	max_dist = min(no_free_segments(sb), LOGFS_NO_AREAS);
+	max_dist = min(no_free_segments(sb), LOGFS_NO_AREAS - 1);
 
 	for (i = max_dist; i >= 0; i--) {
 		this = first_in_list(&super->s_low_list[i]);