[Xen-changelog] [xen-unstable] tmem: Prevent NULL dereference on error case

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Matthew Daley <mattjd@xxxxxxxxx>
# 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@xxxxxxxxx>
Committed-by: Jan Beulich <jbeulich@xxxxxxxx>
---


diff -r 62885b3c34c8 -r 286ef4ced216 xen/common/tmem.c
--- a/xen/common/tmem.c Thu Nov 08 17:58:19 2012 +0100
+++ b/xen/common/tmem.c Mon Nov 12 09:34:57 2012 +0100
@@ -2436,10 +2436,12 @@ 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;
 

_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxx
http://lists.xensource.com/xen-changelog