iommu/amd: Take into account that alloc_dev_data() may return NULL

[ Upstream commit 39ffe39545cd5cb5b8cee9f0469165cf24dc62c2 ]

find_dev_data() does not check whether the return value alloc_dev_data()
is NULL. This was okay once because the pointer was returned once as-is.
Since commit df3f7a6e8e85 ("iommu/amd: Use is_attach_deferred
call-back") the pointer may be used within find_dev_data() so a NULL
check is required.

Cc: Baoquan He <bhe@redhat.com>
Fixes: df3f7a6e8e85 ("iommu/amd: Use is_attach_deferred call-back")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 99a2a57..10190e3 100644 (file)
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -311,6 +311,8 @@ static struct iommu_dev_data *find_dev_data(u16 devid)
 
        if (dev_data == NULL) {
                dev_data = alloc_dev_data(devid);
+               if (!dev_data)
+                       return NULL;
 
                if (translation_pre_enabled(iommu))
                        dev_data->defer_attach = true;