On Wed, Aug 27, 2025 at 05:08:27PM -0400, Matthew Rosato wrote:
zpci_get_iommu_ctrs() returns counter information to be reported as part of device statistics; these counters are stored as part of the s390_domain. The problem, however, is that the identity domain is not backed by an s390_domain and so the conversion via to_s390_domain() yields a bad address that is zero'd initially and read on-demand later via a sysfs read. These counters aren't necessary for the identity domain; just return NULL in this case.
This issue was discovered via KASAN with reports that look like: BUG: KASAN: global-out-of-bounds in zpci_fmb_enable_device when using the identity domain for a device on s390.
Cc: stable@vger.kernel.org Fixes: 64af12c6ec3a ("iommu/s390: implement iommu passthrough via identity domain") Reported-by: Cam Miller cam@linux.ibm.com Signed-off-by: Matthew Rosato mjrosato@linux.ibm.com
drivers/iommu/s390-iommu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
Applied for -rc, thanks.