2020-01-22 00:36:08

by Jerry Snitselaar

Subject: [PATCH] iommu/vt-d: call __dmar_remove_one_dev_info with valid pointer

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 <[email protected]>
Cc: Lu Baolu <[email protected]>
Cc: David Woodhouse <[email protected]>
Cc: [email protected] # 5.3+
Cc: [email protected]
Fixes: ae23bfb68f28 ("iommu/vt-d: Detach domain before using a private one")
Signed-off-by: Jerry Snitselaar <[email protected]>
---
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

2020-01-22 05:48:31

by Lu Baolu

Subject: Re: [PATCH] iommu/vt-d: call __dmar_remove_one_dev_info with valid pointer

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 <[email protected]>
> Cc: Lu Baolu <[email protected]>
> Cc: David Woodhouse <[email protected]>
> Cc: [email protected] # 5.3+
> Cc: [email protected]
> Fixes: ae23bfb68f28 ("iommu/vt-d: Detach domain before using a private one")
> Signed-off-by: Jerry Snitselaar <[email protected]>

Acked-by: Lu Baolu <[email protected]>

Best regards,
baolu