From: Robin Murphy Date: Fri, 11 Nov 2016 17:59:25 +0000 (+0000) Subject: iommu/mediatek: Fix M4Uv1 group refcounting X-Git-Tag: v4.10-rc1~95^2^6~2 X-Git-Url: https://git.kernelconcepts.de/?p=karo-tx-linux.git;a=commitdiff_plain;h=5d1d43b0f6231cfffde61f8774283f170c040776 iommu/mediatek: Fix M4Uv1 group refcounting For each subsequent device assigned to the m4u_group after its initial allocation, we need to take an additional reference. Otherwise, the caller of iommu_group_get_for_dev() will inadvertently remove the reference taken by iommu_group_add_device(), and the group will be freed prematurely if any device is removed. Signed-off-by: Robin Murphy Signed-off-by: Joerg Roedel --- diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c index b8aeb0768483..c7063e9d67d8 100644 --- a/drivers/iommu/mtk_iommu_v1.c +++ b/drivers/iommu/mtk_iommu_v1.c @@ -502,6 +502,8 @@ static struct iommu_group *mtk_iommu_device_group(struct device *dev) data->m4u_group = iommu_group_alloc(); if (IS_ERR(data->m4u_group)) dev_err(dev, "Failed to allocate M4U IOMMU group\n"); + } else { + iommu_group_ref_get(data->m4u_group); } return data->m4u_group; }