From: Jean-Philippe Brucker <jean-philippe@linaro.org> mainline inclusion from mainline-v5.19-rc1 commit cbd23144f7662b00bcde32a938c4a4057e476d68 category: bugfix bugzilla: 190104 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- We currently call arm64_mm_context_put() without holding a reference to the mm, which can result in use-after-free. Call mmgrab()/mmdrop() to ensure the mm only gets freed after we unpinned the ASID. Fixes: 32784a9562fb ("iommu/arm-smmu-v3: Implement iommu_sva_bind/unbind()") Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org> Link: https://lore.kernel.org/r/20220426130444.300556-1-jean-philippe@linaro.org Signed-off-by: Will Deacon <will@kernel.org> Conflicts: drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c [commit 685ace6c824e merged for add trace event] Signed-off-by: Zhang Yuwei <zhangyuwei20@huawei.com> --- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c index afdfd10290be..0040294ad62d 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c @@ -6,6 +6,7 @@ #include <linux/mm.h> #include <linux/mmu_context.h> #include <linux/mmu_notifier.h> +#include <linux/sched/mm.h> #include <linux/slab.h> #include <trace/events/smmu.h> @@ -98,9 +99,14 @@ static struct arm_smmu_ctx_desc *arm_smmu_alloc_shared_cd(struct mm_struct *mm) struct arm_smmu_ctx_desc *cd; struct arm_smmu_ctx_desc *ret = NULL; + /* Don't free the mm until we release the ASID */ + mmgrab(mm); + asid = arm64_mm_context_get(mm); - if (!asid) - return ERR_PTR(-ESRCH); + if (!asid) { + err = -ESRCH; + goto out_drop_mm; + } cd = kzalloc(sizeof(*cd), GFP_KERNEL); if (!cd) { @@ -169,6 +175,8 @@ static struct arm_smmu_ctx_desc *arm_smmu_alloc_shared_cd(struct mm_struct *mm) kfree(cd); out_put_context: arm64_mm_context_put(mm); +out_drop_mm: + mmdrop(mm); return err < 0 ? ERR_PTR(err) : ret; } @@ -177,6 +185,7 @@ static void arm_smmu_free_shared_cd(struct arm_smmu_ctx_desc *cd) if (arm_smmu_free_asid(cd)) { /* Unpin ASID */ arm64_mm_context_put(cd->mm); + mmdrop(cd->mm); kfree(cd); } } -- 2.43.0