From: Krishna Reddy vdumpa@nvidia.com
[ Upstream commit b1a1347912a742a4e1fcdc9df6302dd9dd2c3405 ]
When two devices with same SID are getting probed concurrently through iommu_probe_device(), the iommu_group sometimes is getting allocated more than once as call to arm_smmu_device_group() is not protected for concurrency. Furthermore, it leads to each device holding a different iommu_group and domain pointer, separate IOVA space and only one of the devices' domain is used for translations from IOMMU. This causes accesses from other device to fault or see incorrect translations. Fix this by protecting iommu_group allocation from concurrency in arm_smmu_device_group().
Signed-off-by: Krishna Reddy vdumpa@nvidia.com Signed-off-by: Ashish Mhetre amhetre@nvidia.com Link: https://lore.kernel.org/r/1628570641-9127-3-git-send-email-amhetre@nvidia.co... Signed-off-by: Will Deacon will@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iommu/arm/arm-smmu/arm-smmu.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c index df24bbe3ea4f..7a0fea12d0e5 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c @@ -1475,6 +1475,7 @@ static struct iommu_group *arm_smmu_device_group(struct device *dev) struct iommu_group *group = NULL; int i, idx;
+ mutex_lock(&smmu->stream_map_mutex); for_each_cfg_sme(cfg, fwspec, i, idx) { if (group && smmu->s2crs[idx].group && group != smmu->s2crs[idx].group) @@ -1483,8 +1484,10 @@ static struct iommu_group *arm_smmu_device_group(struct device *dev) group = smmu->s2crs[idx].group; }
- if (group) + if (group) { + mutex_unlock(&smmu->stream_map_mutex); return iommu_group_ref_get(group); + }
if (dev_is_pci(dev)) group = pci_device_group(dev); @@ -1498,6 +1501,7 @@ static struct iommu_group *arm_smmu_device_group(struct device *dev) for_each_cfg_sme(cfg, fwspec, i, idx) smmu->s2crs[idx].group = group;
+ mutex_unlock(&smmu->stream_map_mutex); return group; }