Re: [PATCH v2][next] iommu/vt-d: Fix out-bounds-warning in intel_svm_page_response()

From: Lu Baolu
Date: Wed Jun 09 2021 - 03:42:25 EST


On 4/15/21 4:14 AM, Gustavo A. R. Silva wrote:
Replace a couple of calls to memcpy() with simple assignments in order
to fix the following out-of-bounds warning:

drivers/iommu/intel/svm.c:1198:4: warning: 'memcpy' offset [25, 32] from the object at 'desc' is out of the bounds of referenced subobject 'qw2' with type 'long long unsigned int' at offset 16 [-Warray-bounds]

The problem is that the original code is trying to copy data into a
couple of struct members adjacent to each other in a single call to
memcpy(). This causes a legitimate compiler warning because memcpy()
overruns the length of &desc.qw2 and &resp.qw2, respectively.

This helps with the ongoing efforts to globally enable -Warray-bounds
and get us closer to being able to tighten the FORTIFY_SOURCE routines
on memcpy().

Link:https://github.com/KSPP/linux/issues/109
Signed-off-by: Gustavo A. R. Silva<gustavoars@xxxxxxxxxx>

Queued for v5.14. Thanks!

Best regards,
baolu