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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 600DCC43457 for ; Wed, 14 Oct 2020 19:26:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1CE3B21D7F for ; Wed, 14 Oct 2020 19:26:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390614AbgJNT0h (ORCPT ); Wed, 14 Oct 2020 15:26:37 -0400 Received: from mx.der-flo.net ([193.160.39.236]:35240 "EHLO mx.der-flo.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389668AbgJNT0h (ORCPT ); Wed, 14 Oct 2020 15:26:37 -0400 Received: by mx.der-flo.net (Postfix, from userid 110) id C2BD944097; Wed, 14 Oct 2020 21:26:19 +0200 (CEST) Received: from x201s.fritz.box (p200300D39717440196a31F08d439B120.dip0.t-ipconnect.de [IPv6:2003:d3:9717:4401:96a3:1f08:d439:b120]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx.der-flo.net (Postfix) with ESMTPSA id 6AA1C44097; Wed, 14 Oct 2020 21:25:53 +0200 (CEST) Date: Wed, 14 Oct 2020 21:25:41 +0200 From: Florian Lehner To: John Fastabend Cc: ast@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, dev@der-flo.net Subject: Re: [PATCH bpf-next v2] bpf: Lift hashtab key_size limit Message-ID: <20201014192541.GB9283@x201s.fritz.box> References: <20200922190234.224161-1-dev@der-flo.net> <5f84b24ad1016_24c92208a4@john-XPS-13-9370.notmuch> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5f84b24ad1016_24c92208a4@john-XPS-13-9370.notmuch> Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org John Fastabend wrote: > I think this is OK, but just curious is there a real use-case > that has keys bigger than stack size or is this just an > in-theory observation. The use-case for this patch originates to implement allow/disallow lists for files and file paths. The maximum length of file paths is defined by PATH_MAX with 4096 chars including nul. This limit exceeds MAX_BPF_STACK. Thanks, Florian