linux-kernel - [PATCH][next] ALSA: usb-audio: Fix sum of uninitialized variable sample

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Date:   Fri,  1 Oct 2021 11:44:17 +0100
From:   Colin King <colin.king@...onical.com>
To:     Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>,
        Alexander Tsoy <alexander@...y.me>, alsa-devel@...a-project.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH][next] ALSA: usb-audio: Fix sum of uninitialized variable sample_accum

From: Colin Ian King <colin.king@...onical.com>

Variable sample_accum is not being intialized and then has
ep->sample_rem added to it, leading to a bogus value. One solution
is to initialize it to zero at declaration time, but it is probably
best to just assign it to ep->sample_rem on first use.

Addresses-Coveriry: ("Uninitialized scalar variable")
Fixes: f0bd62b64016 ("ALSA: usb-audio: Improve frames size computation")
Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 sound/usb/endpoint.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index 42c0d2db8ba8..c6a33732db3f 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -182,7 +182,7 @@ static int next_packet_size(struct snd_usb_endpoint *ep, unsigned int avail)
 	if (ep->fill_max)
 		return ep->maxframesize;
 
-	sample_accum += ep->sample_rem;
+	sample_accum = ep->sample_rem;
 	if (sample_accum >= ep->pps) {
 		sample_accum -= ep->pps;
 		ret = ep->packsize[1];
-- 
2.32.0