Per VT-d spec Section 10.4.2 ("Capability Register"), the maximum
number of possible domains is 64K; indeed this is the maximum value
that the cap_ndoms() macro will expand to. Since the value 65536
will not fix in a u16, the 'did' variable must be promoted to an
int, otherwise the test for < 65536 will always be true and the
loop will never end.
The symptom, in my case, was a hung machine during suspend.
Fixes: 3bd4f9112f87 ("iommu/vt-d: Fix overflow of iommu->domains array")
Signed-off-by: Aaron Campbell <[email protected]>
---
drivers/iommu/intel-iommu.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index cfe410e..323dac9 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4602,13 +4602,13 @@ static void free_all_cpu_cached_iovas(unsigned int cpu)
for (i = 0; i < g_num_of_iommus; i++) {
struct intel_iommu *iommu = g_iommus[i];
struct dmar_domain *domain;
- u16 did;
+ int did;
if (!iommu)
continue;
for (did = 0; did < cap_ndoms(iommu->cap); did++) {
- domain = get_iommu_domain(iommu, did);
+ domain = get_iommu_domain(iommu, (u16)did);
if (!domain)
continue;
--
2.7.4
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