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From:   Zhipeng Lu <alexious@zju.edu.cn>
To:     alexious@zju.edu.cn
Cc:     Evan Quan <evan.quan@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>,
        "Pan, Xinhui" <Xinhui.Pan@amd.com>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Hawking Zhang <Hawking.Zhang@amd.com>,
        Ran Sun <sunran001@208suo.com>, Le Ma <le.ma@amd.com>,
        Jammy Zhou <Jammy.Zhou@amd.com>, amd-gfx@lists.freedesktop.org,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: [PATCH] drivers/amd/pm: fix a use-after-free in kv_parse_power_table
Date:   Fri, 15 Dec 2023 00:24:58 +0800
Message-Id: <20231214162500.3483936-1-alexious@zju.edu.cn>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

When ps allocated by kzalloc equals to NULL, kv_parse_power_table
frees adev->pm.dpm.ps that allocated before. However, after the control
flow goes through the following call chains:

kv_parse_power_table
  |-> kv_dpm_init
        |-> kv_dpm_sw_init
	      |-> kv_dpm_fini

The adev->pm.dpm.ps is used in the for loop of kv_dpm_fini after its
first free in kv_parse_power_table and causes a use-after-free bug.

Fixes: a2e73f56fa62 ("drm/amdgpu: Add support for CIK parts")
Signed-off-by: Zhipeng Lu <alexious@zju.edu.cn>
---
 drivers/gpu/drm/amd/pm/legacy-dpm/kv_dpm.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/pm/legacy-dpm/kv_dpm.c b/drivers/gpu/drm/amd/pm/legacy-dpm/kv_dpm.c
index 5d28c951a319..5cb4725c773f 100644
--- a/drivers/gpu/drm/amd/pm/legacy-dpm/kv_dpm.c
+++ b/drivers/gpu/drm/amd/pm/legacy-dpm/kv_dpm.c
@@ -2735,10 +2735,8 @@ static int kv_parse_power_table(struct amdgpu_device *adev)
 		non_clock_info = (struct _ATOM_PPLIB_NONCLOCK_INFO *)
 			&non_clock_info_array->nonClockInfo[non_clock_array_index];
 		ps = kzalloc(sizeof(struct kv_ps), GFP_KERNEL);
-		if (ps == NULL) {
-			kfree(adev->pm.dpm.ps);
+		if (ps == NULL)
 			return -ENOMEM;
-		}
 		adev->pm.dpm.ps[i].ps_priv = ps;
 		k = 0;
 		idx = (u8 *)&power_state->v2.clockInfoIndex[0];
-- 
2.34.1