From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 132C022F747; Wed, 23 Apr 2025 18:16:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745432185; cv=none; b=I+4FwiqAhBZMPSQn5F0/MS8WUoHUbmBCa8nNzeNP/xabxQkIKL0s2ZEBeS1wEQMqYM69wMwcwVN639cDmQk8QkTTxAWymbDwleMP+YeRuNRMGG1wLA0RnXfJ4qxrPeK2smzmjAkh+LwBk9/JI5ZxURr1rHU71m1Uf6fwm8F3lWo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745432185; c=relaxed/simple; bh=zT6WmWKq89q1ikbAI7gacqu8XDLXrdwAY8cZBziJHYE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=q9fuUajc0Yfwqx3y5+f3P0OYQ8Ityuta8c5qn0Jyw4DkLG9Fmqk/UUi1DWQ646ni/Khx11NtpQ7QABUsbiYU8mVXHKkTGPlGzPyDA+bGgECwbUoR9PZmcMIBVFa8xR6HBHR6jJxdtUBW6ZYyhuI/xRtupslip3T7+LFkneG0EDk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=bo6+o6B7; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="bo6+o6B7" Received: from pendragon.ideasonboard.com (81-175-209-231.bb.dnainternet.fi [81.175.209.231]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 0A3B41AE2; Wed, 23 Apr 2025 20:16:20 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1745432181; bh=zT6WmWKq89q1ikbAI7gacqu8XDLXrdwAY8cZBziJHYE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bo6+o6B7qpomUzgb6VyAyvahU/9AFhwyFixGWgT1xW/ydmBFGmedoD6yjc6K2QPDU wWuSusjt7vFT24Hrx7BOZGlXgsd3yc8QNCU52gf4+o6tfKLFhf7omsKlkf1WcHmlZK m4QE4XDAh6R9tYNSYMk7WNMwuCEPFtYuaqZkZNdo= Date: Wed, 23 Apr 2025 21:16:20 +0300 From: Laurent Pinchart To: Mathis Foerst Cc: linux-kernel@vger.kernel.org, Mauro Carvalho Chehab , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Sakari Ailus , linux-media@vger.kernel.org, devicetree@vger.kernel.org, manuel.traut@mt.com, mathis.foerst@zuehlke.com, stable@vger.kernel.org Subject: Re: [PATCH v4 5/6] media: mt9m114: Fix deadlock in get_frame_interval/set_frame_interval Message-ID: <20250423181620.GD2675@pendragon.ideasonboard.com> References: <20250307093140.370061-1-mathis.foerst@mt.com> <20250307093140.370061-6-mathis.foerst@mt.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250307093140.370061-6-mathis.foerst@mt.com> Hi Mathis, Thank you for the patch. On Fri, Mar 07, 2025 at 10:31:39AM +0100, Mathis Foerst wrote: > Getting / Setting the frame interval using the V4L2 subdev pad ops > get_frame_interval/set_frame_interval causes a deadlock, as the > subdev state is locked in the [1] but also in the driver itself. > > In [2] it's described that the caller is responsible to acquire and > release the lock in this case. Therefore, acquiring the lock in the > driver is wrong. > > Remove the lock acquisitions/releases from mt9m114_ifp_get_frame_interval() > and mt9m114_ifp_set_frame_interval(). > > [1] drivers/media/v4l2-core/v4l2-subdev.c - line 1129 > [2] Documentation/driver-api/media/v4l2-subdev.rst > > Fixes: 24d756e914fc ("media: i2c: Add driver for onsemi MT9M114 camera sensor") > Cc: stable@vger.kernel.org > You can delete this blank line. > Signed-off-by: Mathis Foerst Reviewed-by: Laurent Pinchart > --- > drivers/media/i2c/mt9m114.c | 8 -------- > 1 file changed, 8 deletions(-) > > diff --git a/drivers/media/i2c/mt9m114.c b/drivers/media/i2c/mt9m114.c > index 65b9124e464f..79c97ab19be9 100644 > --- a/drivers/media/i2c/mt9m114.c > +++ b/drivers/media/i2c/mt9m114.c > @@ -1644,13 +1644,9 @@ static int mt9m114_ifp_get_frame_interval(struct v4l2_subdev *sd, > if (interval->which != V4L2_SUBDEV_FORMAT_ACTIVE) > return -EINVAL; > > - mutex_lock(sensor->ifp.hdl.lock); > - > ival->numerator = 1; > ival->denominator = sensor->ifp.frame_rate; > > - mutex_unlock(sensor->ifp.hdl.lock); > - > return 0; > } > > @@ -1669,8 +1665,6 @@ static int mt9m114_ifp_set_frame_interval(struct v4l2_subdev *sd, > if (interval->which != V4L2_SUBDEV_FORMAT_ACTIVE) > return -EINVAL; > > - mutex_lock(sensor->ifp.hdl.lock); > - > if (ival->numerator != 0 && ival->denominator != 0) > sensor->ifp.frame_rate = min_t(unsigned int, > ival->denominator / ival->numerator, > @@ -1684,8 +1678,6 @@ static int mt9m114_ifp_set_frame_interval(struct v4l2_subdev *sd, > if (sensor->streaming) > ret = mt9m114_set_frame_rate(sensor); > > - mutex_unlock(sensor->ifp.hdl.lock); > - > return ret; > } > -- Regards, Laurent Pinchart