pstore: skip zero size persistent ram buffer in traverse

In ramoops_pstore_read, a valid prz pointer with zero size buffer will
break traverse of all persistent ram buffers.  The latter buffer might be
lost.

Signed-off-by: Liu ShuoX <shuox.liu@intel.com>
Cc: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Cc: Colin Cross <ccross@android.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 9fe5b13295e024cf9a4777a0688bae6b21e52665..1daed280f1b6c39edd9a8098c687852775e6915e 100644 (file)
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -120,12 +120,12 @@ ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
 
        prz = przs[i];
 
-       if (update) {
-               /* Update old/shadowed buffer. */
+       /* Update old/shadowed buffer. */
+       if (update)
                persistent_ram_save_old(prz);
-               if (!persistent_ram_old_size(prz))
-                       return NULL;
-       }
+
+       if (!persistent_ram_old_size(prz))
+               return NULL;
 
        *typep = type;
        *id = i;