From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 69A821FBD for ; Sun, 30 Jul 2023 13:32:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 48FD6C433C9; Sun, 30 Jul 2023 13:32:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690723943; bh=lNmBx86vKk1Fzpc/aMLSCl3TcRlTY1pUXLYarmo2pTU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=WiyhJf/JlEM3+yEEfz61ekspCLhw4VVM5YFbjKmiPtvC/p46njQUPm5eiwnnx4nRa 7DRNR3xccX+xeUh4F4swYl9TYC9fKRr2xvUvnqktyDhdqhlWxEzl+oC/eyTraxwbxl wz4U0KPCK5tUmDYKY5Wcosh1K19Dmq/Ezl7nOjsGicPTMVwCGV9+BQzoRDvuCpdz0m VdR/hulwoMW9kYakGWfRU8K/a7FBs1ZV/GEAPVUQ32VefgbexhS1xd1+hsVJKHCtVL t5dxMM4A+9s2tS3nbUBSs4JaZmoek+UbkNstf7eny7naYiKSRTZy8Ez6v3y8/6ICwg PQflrtI1Vvn7w== Date: Sun, 30 Jul 2023 16:32:19 +0300 From: Leon Romanovsky To: Jakub Kicinski Cc: davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, Stephen Hemminger Subject: Re: [PATCH net-next] net: make sure we never create ifindex = 0 Message-ID: <20230730133219.GG94048@unreal> References: <20230729015623.17373-1-kuba@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230729015623.17373-1-kuba@kernel.org> On Fri, Jul 28, 2023 at 06:56:23PM -0700, Jakub Kicinski wrote: > Instead of allocating from 1 use proper xa_limit, to protect > ourselves from IDs wrapping back to 0. > > Fixes: 759ab1edb56c ("net: store netdevs in an xarray") > Reported-by: Stephen Hemminger > Link: https://lore.kernel.org/all/20230728162350.2a6d4979@hermes.local/ > Signed-off-by: Jakub Kicinski > --- > CC: leon@kernel.org > --- > net/core/dev.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/net/core/dev.c b/net/core/dev.c > index b58674774a57..2312ca67b95e 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -9587,7 +9587,8 @@ static int dev_index_reserve(struct net *net, u32 ifindex) > > if (!ifindex) > err = xa_alloc_cyclic(&net->dev_by_index, &ifindex, NULL, > - xa_limit_31b, &net->ifindex, GFP_KERNEL); > + XA_LIMIT(1, INT_MAX), &net->ifindex, > + GFP_KERNEL); > else > err = xa_insert(&net->dev_by_index, ifindex, NULL, GFP_KERNEL); > if (err < 0) > @@ -11271,7 +11272,6 @@ static int __net_init netdev_init(struct net *net) > if (net->dev_index_head == NULL) > goto err_idx; > > - net->ifindex = 1; > xa_init_flags(&net->dev_by_index, XA_FLAGS_ALLOC); You don't need to change xa_limit_31b, just change XA_FLAGS_ALLOC to be XA_FLAGS_ALLOC1 and allocations will start from 1. Thanks > > RAW_INIT_NOTIFIER_HEAD(&net->netdev_chain); > -- > 2.41.0 >