linux-kernel - [PATCH 1/1] iommu: Extend mutex lock scope in iommu_probe

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Message-Id: <20211108061349.1985579-1-baolu.lu@linux.intel.com>
Date:   Mon,  8 Nov 2021 14:13:49 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>
Cc:     Ashish Mhetre <amhetre@...dia.com>,
        Jason Gunthorpe <jgg@...dia.com>, kevin.tian@...el.com,
        ashok.raj@...el.com, iommu@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org, Lu Baolu <baolu.lu@...ux.intel.com>
Subject: [PATCH 1/1] iommu: Extend mutex lock scope in iommu_probe_device()

Extend the scope of holding group->mutex so that it can cover the default
domain check/attachment and direct mappings of reserved regions.

Cc: Ashish Mhetre <amhetre@...dia.com>
Fixes: 211ff31b3d33b ("iommu: Fix race condition during default domain allocation")
Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
---
 drivers/iommu/iommu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index dd7863e453a5..8b86406b7162 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -288,11 +288,11 @@ int iommu_probe_device(struct device *dev)
 	 */
 	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);
 		if (ret) {
+			mutex_unlock(&group->mutex);
 			iommu_group_put(group);
 			goto err_release;
 		}
@@ -300,6 +300,7 @@ int iommu_probe_device(struct device *dev)
 
 	iommu_create_device_direct_mappings(group, dev);
 
+	mutex_unlock(&group->mutex);
 	iommu_group_put(group);
 
 	if (ops->probe_finalize)
-- 
2.25.1