From aad7041e721e2bb7aa7755d8ffca0fbc2ee1e17f Mon Sep 17 00:00:00 2001 From: Pan Bian Date: Sun, 23 Apr 2017 18:23:21 +0800 Subject: [PATCH] iommu/amd: Fix incorrect error handling in amd_iommu_bind_pasid() commit 73dbd4a4230216b6a5540a362edceae0c9b4876b upstream. In function amd_iommu_bind_pasid(), the control flow jumps to label out_free when pasid_state->mm and mm is NULL. And mmput(mm) is called. In function mmput(mm), mm is referenced without validation. This will result in a NULL dereference bug. This patch fixes the bug. Signed-off-by: Pan Bian Fixes: f0aac63b873b ('iommu/amd: Don't hold a reference to mm_struct') Signed-off-by: Joerg Roedel Signed-off-by: Greg Kroah-Hartman --- drivers/iommu/amd_iommu_v2.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c index 4831eb910fc7..22160e481794 100644 --- a/drivers/iommu/amd_iommu_v2.c +++ b/drivers/iommu/amd_iommu_v2.c @@ -699,9 +699,9 @@ out_clear_state: out_unregister: mmu_notifier_unregister(&pasid_state->mn, mm); + mmput(mm); out_free: - mmput(mm); free_pasid_state(pasid_state); out: -- 2.34.1