From 143201a6435bf65f0115435e9dc6d95c66b908e9 Mon Sep 17 00:00:00 2001
From: Jernej Skrabec <jernej.skrabec@gmail.com>
Date: Mon, 18 Jul 2022 18:56:49 +0200
Subject: [PATCH] media: cedrus: hevc: Add check for invalid timestamp
Git-commit: 143201a6435bf65f0115435e9dc6d95c66b908e9
Patch-mainline: v6.0-rc1
References: git-fixes

Not all DPB entries will be used most of the time. Unused entries will
thus have invalid timestamps. They will produce negative buffer index
which is not specifically handled. This works just by chance in current
code. It will even produce bogus pointer, but since it's not used, it
won't do any harm.

Let's fix that brittle design by skipping writing DPB entry altogether
if timestamp is invalid.

Fixes: 86caab29da78 ("media: cedrus: Add HEVC/H.265 decoding support")
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/staging/media/sunxi/cedrus/cedrus_h265.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
@@ -147,6 +147,9 @@ static void cedrus_h265_frame_info_write
 			dpb[i].pic_order_cnt[1]
 		};
 
+		if (buffer_index < 0)
+			continue;
+
 		cedrus_h265_frame_info_write_single(ctx, i, dpb[i].field_pic,
 						    pic_order_cnt,
 						    buffer_index);