From: Philipp Zabel <p.zabel@pengutronix.de>
To: linux-media@vger.kernel.org
Cc: kernel@pengutronix.de
Subject: [PATCH] media: coda: fix deadlock between decoder picture run and start command
Date: Thu, 24 Oct 2019 12:32:11 +0200 [thread overview]
Message-ID: <20191024103211.22489-1-p.zabel@pengutronix.de> (raw)
The BIT decoder picture run temporarily locks the bitstream mutex while
the coda device mutex is locked, to refill the bitstream ring buffer.
Consequently, the decoder start command, which locks both mutexes when
flushing the bitstream ring buffer, must lock the coda device mutex
first as well, to avoid an ABBA deadlock.
Fixes: e7fd95849b3c ("media: coda: flush bitstream ring buffer on decoder restart")
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
---
drivers/media/platform/coda/coda-common.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/media/platform/coda/coda-common.c b/drivers/media/platform/coda/coda-common.c
index 73222c0615c0..834f11fe9dc2 100644
--- a/drivers/media/platform/coda/coda-common.c
+++ b/drivers/media/platform/coda/coda-common.c
@@ -1084,16 +1084,16 @@ static int coda_decoder_cmd(struct file *file, void *fh,
switch (dc->cmd) {
case V4L2_DEC_CMD_START:
- mutex_lock(&ctx->bitstream_mutex);
mutex_lock(&dev->coda_mutex);
+ mutex_lock(&ctx->bitstream_mutex);
coda_bitstream_flush(ctx);
- mutex_unlock(&dev->coda_mutex);
dst_vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx,
V4L2_BUF_TYPE_VIDEO_CAPTURE);
vb2_clear_last_buffer_dequeued(dst_vq);
ctx->bit_stream_param &= ~CODA_BIT_STREAM_END_FLAG;
coda_fill_bitstream(ctx, NULL);
mutex_unlock(&ctx->bitstream_mutex);
+ mutex_unlock(&dev->coda_mutex);
break;
case V4L2_DEC_CMD_STOP:
stream_end = false;
--
2.20.1
reply other threads:[~2019-10-24 10:32 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20191024103211.22489-1-p.zabel@pengutronix.de \
--to=p.zabel@pengutronix.de \
--cc=kernel@pengutronix.de \
--cc=linux-media@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.