# HG changeset patch
# User Matthew Daley <mattjd@gmail.com>
# Date 1352709297 -3600
# Node ID 286ef4ced2164f4e9bf52fd0c52248182e69a6e6
# Parent  62885b3c34c84354ead017703a86f0465cb58cf7
tmem: Prevent NULL dereference on error case

If the client / pool IDs given to tmemc_save_get_next_page are invalid,
the calculation of pagesize will dereference NULL.

Fix this by moving the calculation below the appropriate NULL check.

Signed-off-by: Matthew Daley <mattjd@gmail.com>
Committed-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/common/tmem.c
+++ b/xen/common/tmem.c
@@ -2446,10 +2446,12 @@ static NOINLINE int tmemc_save_get_next_
     OID oid;
     int ret = 0;
     struct tmem_handle h;
-    unsigned int pagesize = 1 << (pool->pageshift+12);
+    unsigned int pagesize;
 
     if ( pool == NULL || is_ephemeral(pool) )
         return -1;
+
+    pagesize = 1 << (pool->pageshift + 12);
     if ( bufsize < pagesize + sizeof(struct tmem_handle) )
         return -ENOMEM;