4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> [ 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@xxxxxxxxxx> Fixes: df3f7a6e8e85 ("iommu/amd: Use is_attach_deferred call-back") Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> Signed-off-by: Joerg Roedel <jroedel@xxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/iommu/amd_iommu.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/iommu/amd_iommu.c +++ b/drivers/iommu/amd_iommu.c @@ -310,6 +310,8 @@ static struct iommu_dev_data *find_dev_d 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;