linux-kernel - [PATCH AUTOSEL 5.4 04/27] media: dvb_demux: fix a bug for the continuity counter

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Message-Id: <20230525184238.1943072-4-sashal@kernel.org>
Date:   Thu, 25 May 2023 14:42:13 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     YongSu Yoo <yongsuyoo0215@...il.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Sasha Levin <sashal@...nel.org>, colin.i.king@...il.com,
        tommaso.merciai@...rulasolutions.com, hverkuil-cisco@...all.nl,
        linux-media@...r.kernel.org
Subject: [PATCH AUTOSEL 5.4 04/27] media: dvb_demux: fix a bug for the continuity counter

From: YongSu Yoo <yongsuyoo0215@...il.com>

[ Upstream commit 7efb10d8dc70ea3000cc70dca53407c52488acd1 ]

In dvb_demux.c, some logics exist which compare the expected
continuity counter and the real continuity counter. If they
are not matched each other, both of the expected continuity
counter and the real continuity counter should be printed.
But there exists a bug that the expected continuity counter
is not correctly printed. The expected continuity counter is
replaced with the real countinuity counter + 1 so that
the epected continuity counter is not correclty printed.
This is wrong. This bug is fixed.

Link: https://lore.kernel.org/linux-media/20230305212519.499-1-yongsuyoo0215@gmail.com

Signed-off-by: YongSu Yoo <yongsuyoo0215@...il.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/media/dvb-core/dvb_demux.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/media/dvb-core/dvb_demux.c b/drivers/media/dvb-core/dvb_demux.c
index 39a2c6ccf31d7..9904a170faeff 100644
--- a/drivers/media/dvb-core/dvb_demux.c
+++ b/drivers/media/dvb-core/dvb_demux.c
@@ -125,12 +125,12 @@ static inline int dvb_dmx_swfilter_payload(struct dvb_demux_feed *feed,
 
 	cc = buf[3] & 0x0f;
 	ccok = ((feed->cc + 1) & 0x0f) == cc;
-	feed->cc = cc;
 	if (!ccok) {
 		set_buf_flags(feed, DMX_BUFFER_FLAG_DISCONTINUITY_DETECTED);
 		dprintk_sect_loss("missed packet: %d instead of %d!\n",
 				  cc, (feed->cc + 1) & 0x0f);
 	}
+	feed->cc = cc;
 
 	if (buf[1] & 0x40)	// PUSI ?
 		feed->peslen = 0xfffa;
@@ -310,7 +310,6 @@ static int dvb_dmx_swfilter_section_packet(struct dvb_demux_feed *feed,
 
 	cc = buf[3] & 0x0f;
 	ccok = ((feed->cc + 1) & 0x0f) == cc;
-	feed->cc = cc;
 
 	if (buf[3] & 0x20) {
 		/* adaption field present, check for discontinuity_indicator */
@@ -346,6 +345,7 @@ static int dvb_dmx_swfilter_section_packet(struct dvb_demux_feed *feed,
 		feed->pusi_seen = false;
 		dvb_dmx_swfilter_section_new(feed);
 	}
+	feed->cc = cc;
 
 	if (buf[1] & 0x40) {
 		/* PUSI=1 (is set), section boundary is here */
-- 
2.39.2