From b1a1347912a742a4e1fcdc9df6302dd9dd2c3405 Mon Sep 17 00:00:00 2001 From: Krishna Reddy Date: Tue, 10 Aug 2021 10:14:01 +0530 Subject: iommu/arm-smmu: Fix race condition during iommu_group creation 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 Signed-off-by: Ashish Mhetre Link: https://lore.kernel.org/r/1628570641-9127-3-git-send-email-amhetre@nvidia.com Signed-off-by: Will Deacon --- drivers/iommu/arm/arm-smmu/arm-smmu.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'drivers/iommu/arm') diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c index fc8b932b47d4..f7da8953afbe 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c @@ -1478,6 +1478,7 @@ 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) @@ -1486,8 +1487,10 @@ 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); @@ -1501,6 +1504,7 @@ 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; } -- cgit