linux-kernel - [PATCH] ALSA: usb-audio: initialize variables that could ignore errors

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Date:   Wed, 26 Jan 2022 10:21:42 -0800
From:   trix@...hat.com
To:     perex@...ex.cz, tiwai@...e.com, nathan@...nel.org,
        ndesaulniers@...gle.com, kai.heng.feng@...onical.com,
        jiapeng.chong@...ux.alibaba.com, giun7a@...il.com,
        colin.king@...el.com
Cc:     alsa-devel@...a-project.org, linux-kernel@...r.kernel.org,
        llvm@...ts.linux.dev, Tom Rix <trix@...hat.com>
Subject: [PATCH] ALSA: usb-audio: initialize variables that could ignore errors

From: Tom Rix <trix@...hat.com>

clang static analysis reports this representative issue
mixer.c:1548:35: warning: Assigned value is garbage or undefined
        ucontrol->value.integer.value[0] = val;
                                         ^ ~~~

The filter_error() macro allows errors to be ignored.
If errors can be ignored, initialize variables
so garbage will not be used.

Fixes: 48cc42973509 ("ALSA: usb-audio: Filter error from connector kctl ops, too")
Signed-off-by: Tom Rix <trix@...hat.com>
---
 sound/usb/mixer.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index e8f3f8d622ec5..630766ba259fd 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -1527,6 +1527,10 @@ static int get_connector_value(struct usb_mixer_elem_info *cval,
 		usb_audio_err(chip,
 			"cannot get connectors status: req = %#x, wValue = %#x, wIndex = %#x, type = %d\n",
 			UAC_GET_CUR, validx, idx, cval->val_type);
+
+		if (val)
+			*val = 0;
+
 		return filter_error(cval, ret);
 	}
 
-- 
2.26.3