From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Philip Yang <Philip.Yang@amd.com>,
        Felix Kuehling <Felix.Kuehling@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 36/42] drm/amdkfd: fix double free mem structure
Date:   Wed, 15 Dec 2021 18:21:17 +0100
Message-Id: <20211215172027.886545805@linuxfoundation.org>
In-Reply-To: <20211215172026.641863587@linuxfoundation.org>
References: <20211215172026.641863587@linuxfoundation.org>
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From: Philip Yang <Philip.Yang@amd.com>

[ Upstream commit 494f2e42ce4a9ddffb5d8c5b2db816425ef90397 ]

drm_gem_object_put calls release_notify callback to free the mem
structure and unreserve_mem_limit, move it down after the last access
of mem and make it conditional call.

Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index cdf46bd0d8d5b..ab36cce59d2e4 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -1393,7 +1393,7 @@ int amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu(
 	struct sg_table *sg = NULL;
 	uint64_t user_addr = 0;
 	struct amdgpu_bo *bo;
-	struct drm_gem_object *gobj;
+	struct drm_gem_object *gobj = NULL;
 	u32 domain, alloc_domain;
 	u64 alloc_flags;
 	int ret;
@@ -1503,14 +1503,16 @@ int amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu(
 	remove_kgd_mem_from_kfd_bo_list(*mem, avm->process_info);
 	drm_vma_node_revoke(&gobj->vma_node, drm_priv);
 err_node_allow:
-	drm_gem_object_put(gobj);
 	/* Don't unreserve system mem limit twice */
 	goto err_reserve_limit;
 err_bo_create:
 	unreserve_mem_limit(adev, size, alloc_domain, !!sg);
 err_reserve_limit:
 	mutex_destroy(&(*mem)->lock);
-	kfree(*mem);
+	if (gobj)
+		drm_gem_object_put(gobj);
+	else
+		kfree(*mem);
 err:
 	if (sg) {
 		sg_free_table(sg);
-- 
2.33.0