Fix an hypothetical issue in processMultibulkBuffer().

1 files changed, 5 insertions, 1 deletions

diff --git a/src/networking.c b/src/networking.c
index dc8b358c2..13c4314fe 100644
--- a/src/networking.c
+++ b/src/networking.c
@@ -925,15 +925,19 @@ int processMultibulkBuffer(redisClient *c) {
 
             pos += newline-(c->querybuf+pos)+2;
             if (ll >= REDIS_MBULK_BIG_ARG) {
+                size_t qblen;
+
                 /* If we are going to read a large object from network
                  * try to make it likely that it will start at c->querybuf
                  * boundary so that we can optimize object creation
                  * avoiding a large copy of data. */
                 c->querybuf = sdsrange(c->querybuf,pos,-1);
                 pos = 0;
+                qblen = sdslen(c->querybuf);
                 /* Hint the sds library about the amount of bytes this string is
                  * going to contain. */
-                c->querybuf = sdsMakeRoomFor(c->querybuf,ll+2-sdslen(c->querybuf));
+                if (qblen < ll+2)
+                    c->querybuf = sdsMakeRoomFor(c->querybuf,ll+2-qblen);
             }
             c->bulklen = ll;
         }