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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7EA94C433F5 for ; Mon, 3 Oct 2022 13:22:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229957AbiJCNWj (ORCPT ); Mon, 3 Oct 2022 09:22:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52220 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229644AbiJCNWh (ORCPT ); Mon, 3 Oct 2022 09:22:37 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 1944140542 for ; Mon, 3 Oct 2022 06:22:35 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 34C3816F8; Mon, 3 Oct 2022 06:22:42 -0700 (PDT) Received: from e120937-lin (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 80B403F73B; Mon, 3 Oct 2022 06:22:34 -0700 (PDT) Date: Mon, 3 Oct 2022 14:22:32 +0100 From: Cristian Marussi To: Shivnandan Kumar Cc: sudeep.holla@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, quic_rgottimu@quicinc.com, quic_avajid@quicinc.com Subject: Re: Query regarding "firmware: arm_scmi: Free mailbox channels if probe fails" Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 30, 2022 at 06:29:02PM +0530, Shivnandan Kumar wrote: > hi Cristian, Hi Shivnandan, > > Thanks for your support in providing the patch to try. > > I found one race condition in our downstream mbox controller driver while > accessing con_priv, when I serialized access to this, issue is not seen on 3 > days of testing. Good to hear that you find the issue. > > As you rightly mentioned that your provided patch will impact all the other > users. > > Also if  we take your provided patch, same race still exists while accessing > con_priv in our downstream mbox controller so this issue will still be > there. > Yes indeed, even though I think that race in the mailbox core between RX path and chan_free could still be theoretically possible it does not seem to me appropriate to try to fix it now that you cannot reproduce it anymore and no other mailbox user has ever raised this concern (even though, as said, the proper solution to that race wont probably be directly in the mailbox-core as in my experimental two liners..) > So, we are planning to merge the patch( serialized access to con_priv) in > our downstream mbox controller now. > Ok, just out of curiosity, once done, can you point me at your downstream public sources so I can see the issue and the fix that you are applying to your trees ? Thanks, Cristian