[Xen-devel] [PATCH] passthrough/amd: avoid reading an uninitialized variable.

[Tim Deegan <tim@xxxxxxx>]

update_intremap_entry_from_msi() doesn't write to its data pointer on
some error paths, so we copying that variable into the msg would count
as undefined behaviour.

Signed-off-by: Tim Deegan <tim@xxxxxxx>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
Cc: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@xxxxxxx>
---
I'm not sure whether we ought to be writing some default value
instead.  Happy to respin if someone knowledgeable can advise.
---
 xen/drivers/passthrough/amd/iommu_intr.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/xen/drivers/passthrough/amd/iommu_intr.c 
b/xen/drivers/passthrough/amd/iommu_intr.c
index c1b76fb..c097d52 100644
--- a/xen/drivers/passthrough/amd/iommu_intr.c
+++ b/xen/drivers/passthrough/amd/iommu_intr.c
@@ -529,10 +529,11 @@ int amd_iommu_msi_msg_update_ire(
     } while ( PCI_SLOT(bdf) == PCI_SLOT(pdev->devfn) );
 
     if ( !rc )
+    {
         for ( i = 1; i < nr; ++i )
             msi_desc[i].remap_index = msi_desc->remap_index + i;
-
-    msg->data = data;
+        msg->data = data;
+    }
     return rc;
 }
 
-- 
2.1.4


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