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>

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]);