UBI: Fix double free after do_sync_erase()

If the erase worker is unable to erase a PEB it will
free the ubi_wl_entry itself.
The failing ubi_wl_entry must not free()'d again after
do_sync_erase() returns.

Cc: <stable@vger.kernel.org>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

1 files changed, 3 insertions, 7 deletions

diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index 7d2a25f96804..834f6fe1f5fa 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -1216,7 +1216,6 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
 
         err = do_sync_erase(ubi, e1, vol_id, lnum, 0);
         if (err) {
-                kmem_cache_free(ubi_wl_entry_slab, e1);
                 if (e2)
                         kmem_cache_free(ubi_wl_entry_slab, e2);
                 goto out_ro;
@@ -1230,10 +1229,8 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
                 dbg_wl("PEB %d (LEB %d:%d) was put meanwhile, erase",
                        e2->pnum, vol_id, lnum);
                 err = do_sync_erase(ubi, e2, vol_id, lnum, 0);
-                if (err) {
-                        kmem_cache_free(ubi_wl_entry_slab, e2);
+                if (err)
                         goto out_ro;
-                }
         }
 
         dbg_wl("done");
@@ -1269,10 +1266,9 @@ out_not_moved:
 
         ubi_free_vid_hdr(ubi, vid_hdr);
         err = do_sync_erase(ubi, e2, vol_id, lnum, torture);
-        if (err) {
-                kmem_cache_free(ubi_wl_entry_slab, e2);
+        if (err)
                 goto out_ro;
-        }
+
         mutex_unlock(&ubi->move_mutex);
         return 0;