Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Nicolas Dufresne <nicolas.dufresne@collabora.com>,
        Dmitry Osipenko <dmitry.osipenko@collabora.com>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Mauro Carvalho Chehab <mchehab@kernel.org>
Subject: [PATCH 6.0 171/862] media: cedrus: Fix endless loop in cedrus_h265_skip_bits()
Date:   Wed, 19 Oct 2022 10:24:18 +0200
Message-Id: <20221019083257.513939871@linuxfoundation.org>
In-Reply-To: <20221019083249.951566199@linuxfoundation.org>
References: <20221019083249.951566199@linuxfoundation.org>
User-Agent: quilt/0.67
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Dmitry Osipenko <dmitry.osipenko@collabora.com>

commit 91db7a3fc7fe670cf1770a398a43bb4a1f776bf1 upstream.

The busy status bit may never de-assert if number of programmed skip
bits is incorrect, resulting in a kernel hang because the bit is polled
endlessly in the code. Fix it by adding timeout for the bit-polling.
This problem is reproducible by setting the data_bit_offset field of
the HEVC slice params to a wrong value by userspace.

Cc: stable@vger.kernel.org
Fixes: 7678c5462680 (media: cedrus: Fix decoding for some HEVC videos)
Reported-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/staging/media/sunxi/cedrus/cedrus_h265.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
@@ -234,8 +234,9 @@ static void cedrus_h265_skip_bits(struct
 		cedrus_write(dev, VE_DEC_H265_TRIGGER,
 			     VE_DEC_H265_TRIGGER_FLUSH_BITS |
 			     VE_DEC_H265_TRIGGER_TYPE_N_BITS(tmp));
-		while (cedrus_read(dev, VE_DEC_H265_STATUS) & VE_DEC_H265_STATUS_VLD_BUSY)
-			udelay(1);
+
+		if (cedrus_wait_for(dev, VE_DEC_H265_STATUS, VE_DEC_H265_STATUS_VLD_BUSY))
+			dev_err_ratelimited(dev->dev, "timed out waiting to skip bits\n");
 
 		count += tmp;
 	}