linux-kernel - [PATCH 4/7] drm/amd/powerplay: Zero initialize freq in smu_v11_0_get_current_clk

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190704055217.45860-5-natechancellor@gmail.com>
Date:   Wed,  3 Jul 2019 22:52:15 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        "David (ChunMing) Zhou" <David1.Zhou@....com>,
        Harry Wentland <harry.wentland@....com>,
        Leo Li <sunpeng.li@....com>, Rex Zhu <rex.zhu@....com>,
        Evan Quan <evan.quan@....com>
Cc:     David Airlie <airlied@...ux.ie>, Daniel Vetter <daniel@...ll.ch>,
        amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, clang-built-linux@...glegroups.com,
        Nathan Chancellor <natechancellor@...il.com>
Subject: [PATCH 4/7] drm/amd/powerplay: Zero initialize freq in smu_v11_0_get_current_clk_freq

clang warns (trimmed for brevity):

drivers/gpu/drm/amd/amdgpu/../powerplay/smu_v11_0.c:1098:10: warning:
variable 'freq' is used uninitialized whenever '?:' condition is false
[-Wsometimes-uninitialized]
                ret =  smu_get_current_clk_freq_by_table(smu, clk_id, &freq);
                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If get_current_clk_freq_by_table is ever NULL, freq will fail to be
properly initialized. Zero initialize it to avoid using uninitialized
stack values.

smu_get_current_clk_freq_by_table expands to a ternary operator
conditional on smu->funcs->get_current_clk_freq_by_table being not NULL.
When this is false, freq will be uninitialized. Zero initialize freq to
avoid using random stack values if that ever happens.

Fixes: e36182490dec ("drm/amd/powerplay: fix dpm freq unit error (10KHz -> Mhz)")
Link: https://github.com/ClangBuiltLinux/linux/issues/585
Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
---
 drivers/gpu/drm/amd/powerplay/smu_v11_0.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/powerplay/smu_v11_0.c b/drivers/gpu/drm/amd/powerplay/smu_v11_0.c
index 632a20587c8b..a6f8cd6df7f1 100644
--- a/drivers/gpu/drm/amd/powerplay/smu_v11_0.c
+++ b/drivers/gpu/drm/amd/powerplay/smu_v11_0.c
@@ -1088,7 +1088,7 @@ static int smu_v11_0_get_current_clk_freq(struct smu_context *smu,
 					  uint32_t *value)
 {
 	int ret = 0;
-	uint32_t freq;
+	uint32_t freq = 0;
 
 	if (clk_id >= SMU_CLK_COUNT || !value)
 		return -EINVAL;
-- 
2.22.0