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* [PATCH] iommu/vt-d: call __dmar_remove_one_dev_info with valid pointer
@ 2020-01-22  0:34 Jerry Snitselaar
  2020-01-22  5:43 ` Lu Baolu
  0 siblings, 1 reply; 2+ messages in thread
From: Jerry Snitselaar @ 2020-01-22  0:34 UTC (permalink / raw)
  To: iommu; +Cc: David Woodhouse, linux-kernel, stable

It is possible for archdata.iommu to be set to
DEFER_DEVICE_DOMAIN_INFO or DUMMY_DEVICE_DOMAIN_INFO so check for
those values before calling __dmar_remove_one_dev_info. Without a
check it can result in a null pointer dereference. This has been seen
while booting a kdump kernel on an HP dl380 gen9.

Cc: Joerg Roedel <joro@8bytes.org>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: stable@vger.kernel.org # 5.3+
Cc: linux-kernel@vger.kernel.org
Fixes: ae23bfb68f28 ("iommu/vt-d: Detach domain before using a private one")
Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
---
 drivers/iommu/intel-iommu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 1801f0aaf013..932267f49f9a 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -5163,7 +5163,8 @@ static void dmar_remove_one_dev_info(struct device *dev)
 
 	spin_lock_irqsave(&device_domain_lock, flags);
 	info = dev->archdata.iommu;
-	if (info)
+	if (info && info != DEFER_DEVICE_DOMAIN_INFO
+	    && info != DUMMY_DEVICE_DOMAIN_INFO)
 		__dmar_remove_one_dev_info(info);
 	spin_unlock_irqrestore(&device_domain_lock, flags);
 }
-- 
2.24.0

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^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] iommu/vt-d: call __dmar_remove_one_dev_info with valid pointer
  2020-01-22  0:34 [PATCH] iommu/vt-d: call __dmar_remove_one_dev_info with valid pointer Jerry Snitselaar
@ 2020-01-22  5:43 ` Lu Baolu
  0 siblings, 0 replies; 2+ messages in thread
From: Lu Baolu @ 2020-01-22  5:43 UTC (permalink / raw)
  To: Jerry Snitselaar, iommu; +Cc: David Woodhouse, linux-kernel, stable

On 1/22/20 8:34 AM, Jerry Snitselaar wrote:
> It is possible for archdata.iommu to be set to
> DEFER_DEVICE_DOMAIN_INFO or DUMMY_DEVICE_DOMAIN_INFO so check for
> those values before calling __dmar_remove_one_dev_info. Without a
> check it can result in a null pointer dereference. This has been seen
> while booting a kdump kernel on an HP dl380 gen9.
> 
> Cc: Joerg Roedel <joro@8bytes.org>
> Cc: Lu Baolu <baolu.lu@linux.intel.com>
> Cc: David Woodhouse <dwmw2@infradead.org>
> Cc: stable@vger.kernel.org # 5.3+
> Cc: linux-kernel@vger.kernel.org
> Fixes: ae23bfb68f28 ("iommu/vt-d: Detach domain before using a private one")
> Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>

Acked-by: Lu Baolu <baolu.lu@linux.intel.com>

Best regards,
baolu
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^ permalink raw reply	[flat|nested] 2+ messages in thread

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2020-01-22  0:34 [PATCH] iommu/vt-d: call __dmar_remove_one_dev_info with valid pointer Jerry Snitselaar
2020-01-22  5:43 ` Lu Baolu

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