From: Ashish Mhetre <amhetre@xxxxxxxxxx> [ Upstream commit 211ff31b3d33b56aa12937e898c9280d07daf0d9 ] When two devices with same SID are getting probed concurrently through iommu_probe_device(), the iommu_domain sometimes is getting allocated more than once as call to iommu_alloc_default_domain() is not protected for concurrency. Furthermore, it leads to each device holding a different iommu_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_alloc_default_domain() call with group->mutex and let all devices with same SID share same iommu_domain. Signed-off-by: Ashish Mhetre <amhetre@xxxxxxxxxx> Link: https://lore.kernel.org/r/1628570641-9127-2-git-send-email-amhetre@xxxxxxxxxx Signed-off-by: Will Deacon <will@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/iommu/iommu.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 63f0af10c403..3050cc4b02bc 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -273,7 +273,9 @@ int iommu_probe_device(struct device *dev) * support default domains, so the return value is not yet * checked. */ + mutex_lock(&group->mutex); iommu_alloc_default_domain(group, dev); + mutex_unlock(&group->mutex); if (group->default_domain) { ret = __iommu_attach_device(group->default_domain, dev); -- 2.30.2
