bio: Fix potential memory leak in bio_find_or_create_slab()

Do not leak memory by updating pointer with potentially NULL realloc return value.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 6 insertions, 5 deletions

diff --git a/fs/bio.c b/fs/bio.c
index 73922abba832..fed1f799cb56 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -73,7 +73,7 @@ static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size)
 {
         unsigned int sz = sizeof(struct bio) + extra_size;
         struct kmem_cache *slab = NULL;
-        struct bio_slab *bslab;
+        struct bio_slab *bslab, *new_bio_slabs;
         unsigned int i, entry = -1;
 
         mutex_lock(&bio_slab_lock);
@@ -97,11 +97,12 @@ static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size)
 
         if (bio_slab_nr == bio_slab_max && entry == -1) {
                 bio_slab_max <<= 1;
-                bio_slabs = krealloc(bio_slabs,
-                                     bio_slab_max * sizeof(struct bio_slab),
-                                     GFP_KERNEL);
-                if (!bio_slabs)
+                new_bio_slabs = krealloc(bio_slabs,
+                                         bio_slab_max * sizeof(struct bio_slab),
+                                         GFP_KERNEL);
+                if (!new_bio_slabs)
                         goto out_unlock;
+                bio_slabs = new_bio_slabs;
         }
         if (entry == -1)
                 entry = bio_slab_nr++;