From patchwork Thu Oct 24 10:32:11 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Philipp Zabel X-Patchwork-Id: 11208887 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2EC061515 for ; Thu, 24 Oct 2019 10:32:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 178792084C for ; Thu, 24 Oct 2019 10:32:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2438816AbfJXKcN (ORCPT ); Thu, 24 Oct 2019 06:32:13 -0400 Received: from metis.ext.pengutronix.de ([85.220.165.71]:47489 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2409175AbfJXKcN (ORCPT ); Thu, 24 Oct 2019 06:32:13 -0400 Received: from dude02.hi.pengutronix.de ([2001:67c:670:100:1d::28] helo=dude02.pengutronix.de.) by metis.ext.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1iNaPc-0008F0-11; Thu, 24 Oct 2019 12:32:12 +0200 From: Philipp Zabel 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 Message-Id: <20191024103211.22489-1-p.zabel@pengutronix.de> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::28 X-SA-Exim-Mail-From: p.zabel@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-media@vger.kernel.org Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org 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 --- 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;