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authorDavid Vrabel <david.vrabel@citrix.com>2014-09-02 18:21:29 +0400
committerDavid Vrabel <david.vrabel@citrix.com>2014-09-04 16:13:13 +0400
commite9de2e5fd602c4f5ddf212d3837b19ad4f5878ad (patch)
tree5de52049ae43fe91f89196a76c23c24fc32e554e /drivers/xen
parent3dcf63677d4eb7fdfc13290c8558c301d2588fe8 (diff)
downloadlinux-e9de2e5fd602c4f5ddf212d3837b19ad4f5878ad.tar.xz
xen/gntalloc: fix oops after runnning out of grant refs
Only set gref->gref_id if foreign access was successfully granted and the grant ref is valid. If gref->gref_id == -ENOSPC the test in __del_gref() would incorrectly attempt to end foreign access (because grant_ref_t is unsigned). Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reported-by: Dave Scott <dave.scott@citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/gntalloc.c10
1 files changed, 4 insertions, 6 deletions
diff --git a/drivers/xen/gntalloc.c b/drivers/xen/gntalloc.c
index 787d17945418..8ed2bb4f6f21 100644
--- a/drivers/xen/gntalloc.c
+++ b/drivers/xen/gntalloc.c
@@ -141,13 +141,11 @@ static int add_grefs(struct ioctl_gntalloc_alloc_gref *op,
goto undo;
/* Grant foreign access to the page. */
- gref->gref_id = gnttab_grant_foreign_access(op->domid,
+ rc = gnttab_grant_foreign_access(op->domid,
pfn_to_mfn(page_to_pfn(gref->page)), readonly);
- if ((int)gref->gref_id < 0) {
- rc = gref->gref_id;
+ if (rc < 0)
goto undo;
- }
- gref_ids[i] = gref->gref_id;
+ gref_ids[i] = gref->gref_id = rc;
}
/* Add to gref lists. */
@@ -193,7 +191,7 @@ static void __del_gref(struct gntalloc_gref *gref)
gref->notify.flags = 0;
- if (gref->gref_id > 0) {
+ if (gref->gref_id) {
if (gnttab_query_foreign_access(gref->gref_id))
return;