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 87D7AC4332F for ; Tue, 12 Dec 2023 11:16:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346185AbjLLLQC (ORCPT ); Tue, 12 Dec 2023 06:16:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56740 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229963AbjLLLQA (ORCPT ); Tue, 12 Dec 2023 06:16:00 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D5C80B7 for ; Tue, 12 Dec 2023 03:16:06 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E855FC433C8; Tue, 12 Dec 2023 11:16:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1702379766; bh=uYwwLlsIzQYDAj0R5783tUUQONQgc91PncKROKCTvL0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ClmUQ5Sy0FxUMQx8S4IKnViITsSypmc+mECTKMc5IgH3dGZNb0fp1CiuIK/GlpFXc Vq+lycJe/grle9iUp9xrNWRJBAbM9ZSZUoxhIDWmcvZ5OCx5qQBADbMioF/yTgoHvj u6EPVXKqqQWKYG+sDOlOB65sAl3p9fx+8Juawu6i+ISIjsC1Kt8HyBEGVLkrLrnef5 T/hjZw78hPygBbXIGovEdcFUpQuzsHMVwsDXW5qnVQ4vVMsH/rrCQt31SYt5K/5qYx VUtY24tOiA0U/cdr65Y1M/fp8lbtQgqXRY9Mf+YNPsoIV6/IRQCbW944WE+2uM5+hq m/S4XQMSDOA6w== Date: Tue, 12 Dec 2023 11:16:01 +0000 From: Simon Horman To: Suman Ghosh Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, sgoutham@marvell.com, sbhatta@marvell.com, jerinj@marvell.com, gakula@marvell.com, hkelam@marvell.com, lcherian@marvell.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [net-next PATCH] octeontx2-af: Fix multicast/mirror group lock/unlock issue Message-ID: <20231212111601.GY5817@kernel.org> References: <20231212091558.49579-1-sumang@marvell.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231212091558.49579-1-sumang@marvell.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 12, 2023 at 02:45:58PM +0530, Suman Ghosh wrote: > As per the existing implementation, there exists a race between finding > a multicast/mirror group entry and deleting that entry. The group lock > was taken and released independently by rvu_nix_mcast_find_grp_elem() > function. Which is incorrect and group lock should be taken during the > entire operation of group updation/deletion. This patch fixes the same. > > Fixes: 51b2804c19cd ("octeontx2-af: Add new mbox to support multicast/mirror offload") > Signed-off-by: Suman Ghosh ... > @@ -6306,6 +6310,13 @@ int rvu_mbox_handler_nix_mcast_grp_destroy(struct rvu *rvu, > return err; > > mcast_grp = &nix_hw->mcast_grp; > + > + /* If AF is requesting for the deletion, > + * then AF is already taking the lock > + */ > + if (!req->is_af) > + mutex_lock(&mcast_grp->mcast_grp_lock); > + > elem = rvu_nix_mcast_find_grp_elem(mcast_grp, req->mcast_grp_idx); > if (!elem) Hi Suman, Does mcast_grp_lock need to be released here? If so, I would suggest a goto label, say unlock_grp. > return NIX_AF_ERR_INVALID_MCAST_GRP; > @@ -6333,12 +6344,6 @@ int rvu_mbox_handler_nix_mcast_grp_destroy(struct rvu *rvu, > mutex_unlock(&mcast->mce_lock); > > delete_grp: > - /* If AF is requesting for the deletion, > - * then AF is already taking the lock > - */ > - if (!req->is_af) > - mutex_lock(&mcast_grp->mcast_grp_lock); > - > list_del(&elem->list); > kfree(elem); > mcast_grp->count--; > @@ -6370,9 +6375,20 @@ int rvu_mbox_handler_nix_mcast_grp_update(struct rvu *rvu, > return err; > > mcast_grp = &nix_hw->mcast_grp; > + > + /* If AF is requesting for the updation, > + * then AF is already taking the lock > + */ > + if (!req->is_af) > + mutex_lock(&mcast_grp->mcast_grp_lock); > + > elem = rvu_nix_mcast_find_grp_elem(mcast_grp, req->mcast_grp_idx); > - if (!elem) > + if (!elem) { > + if (!req->is_af) > + mutex_unlock(&mcast_grp->mcast_grp_lock); > + > return NIX_AF_ERR_INVALID_MCAST_GRP; > + } > > /* If any pcifunc matches the group's pcifunc, then we can > * delete the entire group. > @@ -6383,8 +6399,11 @@ int rvu_mbox_handler_nix_mcast_grp_update(struct rvu *rvu, > /* Delete group */ > dreq.hdr.pcifunc = elem->pcifunc; > dreq.mcast_grp_idx = elem->mcast_grp_idx; > - dreq.is_af = req->is_af; > + dreq.is_af = 1; > rvu_mbox_handler_nix_mcast_grp_destroy(rvu, &dreq, NULL); > + if (!req->is_af) > + mutex_unlock(&mcast_grp->mcast_grp_lock); > + > return 0; > } > } > @@ -6467,5 +6486,8 @@ int rvu_mbox_handler_nix_mcast_grp_update(struct rvu *rvu, > > done: I think it would be good to rename this label, say unlock_mce; > mutex_unlock(&mcast->mce_lock); Add a new label here, say unlock_grp; And jump to this label whenever there is a need for the mutex_unlock() below. > + if (!req->is_af) > + mutex_unlock(&mcast_grp->mcast_grp_lock); > + > return ret; > } > -- > 2.25.1 >