From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ADC3BC433F5 for ; Wed, 13 Oct 2021 13:09:56 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 73824610FE for ; Wed, 13 Oct 2021 13:09:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 73824610FE Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id D07C56EA60; Wed, 13 Oct 2021 13:09:54 +0000 (UTC) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by gabe.freedesktop.org (Postfix) with ESMTPS id 155B66EA56; Wed, 13 Oct 2021 13:09:53 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 636A1610FC; Wed, 13 Oct 2021 13:09:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1634130592; bh=7m7EfH/zUZP99e4EZpqOWzO8X2MkRjqzezczEyYF0zI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Wx7I7ej+sxeJQCf9x4/LREq2NXMV01Tq8P+tnbeia7QrIxq0cY7L8deG75Z3DXX37 oNOecuKpLP5egwHkQcgDxvJeu8hEwRzPaWa/k4RFSCKRtiNWfjE71HkGAm9ES6Vyr2 LJhtwm15yKqYxG/rcAoEIXiE/8bw0Ss9OmlXjktQ= Date: Wed, 13 Oct 2021 15:09:50 +0200 From: Greg KH To: Kai Vehmanen Cc: dri-devel@lists.freedesktop.org, Takashi Iwai , alsa-devel@alsa-project.org, jani.nikula@intel.com, Imre Deak , Russell King , "Rafael J . Wysocki" , intel-gfx@lists.freedesktop.org, Russell King Message-ID: References: <20210922085432.2776886-1-kai.vehmanen@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Intel-gfx] [PATCH v2] component: do not leave master devres group open after bind X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Wed, Oct 06, 2021 at 04:47:57PM +0300, Kai Vehmanen wrote: > Hi, > > On Tue, 5 Oct 2021, Greg KH wrote: > > > On Wed, Sep 22, 2021 at 11:54:32AM +0300, Kai Vehmanen wrote: > > > In current code, the devres group for aggregate master is left open > > > after call to component_master_add_*(). This leads to problems when the > > > master does further managed allocations on its own. When any > > > participating driver calls component_del(), this leads to immediate > > > release of resources. > [...] > > > the devres group, and by closing the devres group after > > > the master->ops->bind() call is done. This allows devres allocations > > > done by the driver acting as master to be isolated from the binding state > > > of the aggregate driver. This modifies the logic originally introduced in > > > commit 9e1ccb4a7700 ("drivers/base: fix devres handling for master device") > > > > > > BugLink: https://gitlab.freedesktop.org/drm/intel/-/issues/4136 > > > Signed-off-by: Kai Vehmanen > > > Acked-by: Imre Deak > > > Acked-by: Russell King (Oracle) > > > > What commit does this "fix:"? And does it need to go to stable > > kernel(s)? > > I didn't put a "Fixes" on the original commit 9e1ccb4a7700 > ("drivers/base: fix devres handling for master device") as it alone > didn't cause problems. It did open the door for possible devres issues > for anybody calling component_master_add_(). > > On audio side, this surfaced with the more recent commit 3fcaf24e5dce > ("ALSA: hda: Allocate resources with device-managed APIs"). In theory one > could have hit issues already before, but this made it very easy to hit > on actual systems. > > If I'd have to pick one, it would be 9e1ccb4a7700 ("drivers/base: fix > devres handling for master device"). And yes, given comments on this > thread, I'd say this needs to go to stable kernels. Then please add a fixes: line and a cc: stable line and resend. thanks, greg k-h