2021-11-08 11:06:40

by Lu Baolu

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 <[email protected]>
Fixes: 211ff31b3d33b ("iommu: Fix race condition during default domain allocation")
Signed-off-by: Lu Baolu <[email protected]>
---
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

2021-12-06 11:40:16

by Joerg Roedel

Subject: Re: [PATCH 1/1] iommu: Extend mutex lock scope in iommu_probe_device()

On Mon, Nov 08, 2021 at 02:13:49PM +0800, Lu Baolu wrote:
> 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 <[email protected]>
> Fixes: 211ff31b3d33b ("iommu: Fix race condition during default domain allocation")
> Signed-off-by: Lu Baolu <[email protected]>
> ---
> drivers/iommu/iommu.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)

Applied, thanks. The __iommu_attach_device() function is called under
group->mutex everywhere else, so it makes here too.

Regards,

Joerg