From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Kroah-Hartman Subject: Re: [PATCH 4/4] [RFC] staging/net: move AF_X25 into drivers/staging Date: Mon, 9 Dec 2019 16:41:01 +0100 Message-ID: <20191209154101.GB1284708@kroah.com> References: <20191209151256.2497534-1-arnd@arndb.de> <20191209151256.2497534-4-arnd@arndb.de> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575906064; bh=xchqQrFdZC9lF1bCvucvR91oCh8m2y80Hp0P0ydGrDk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=T6ptTT5Dvl7Ke0t4vlq8m8f4XwnvIcTx03hZ7ubXpADtuyaQreXvuWT/F3tAUw0iO nv0m8FLvmrHqSej/FKphn7MbmX/ckC1wKOZ9PaDgJOXkqAH1c+1QVOtZrqdxcZIKLV S5/fZKB6PwdMdpgk8HQYC1Tf4PzP6toHs+047CQY= Content-Disposition: inline In-Reply-To: <20191209151256.2497534-4-arnd@arndb.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Arnd Bergmann Cc: "David S. Miller" , Krzysztof Halasa , devel@driverdev.osuosl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Eric Biggers , Andrew Hendry , linux-x25@vger.kernel.org, Kevin Curtis , "R.J.Dunlop" , Zhao Qiang , syzbot+429c200ffc8772bfe070@syzkaller.appspotmail.com, syzbot+eec0c87f31a7c3b66f7b@syzkaller.appspotmail.com On Mon, Dec 09, 2019 at 04:12:56PM +0100, Arnd Bergmann wrote: > syzbot keeps finding issues in the X.25 implementation that nobody is > interested in fixing. Given that all the x25 patches of the past years > that are not global cleanups tend to fix user-triggered oopses, is it > time to just retire the subsystem? > > I looked a bit closer and found: > > - we used to support x25 hardware in linux, but with WAN_ROUTER > removed in linux-3.9 and isdn4linux removed in 5.3, there is only hdlc, > ethernet and the N_X25 tty ldisc left. Out of these, only HDLC_X25 made > it beyond the experimental stage, so this is probably what everyone > uses if there are users at all. > > - The most common hdlc hardware that people seem to be using are > the "farsync" PCIe and USB adapters. Linux only has drivers for the > older PCI devices from that series, but no hardware that works on > modern systems. > > - The manufacturer still updates their own kernel drivers and provides > support, but ships that with a fork or rewrite of the subsystem > code now. Kevin Curtis is also listed as maintainer, but appears to > have given up in 2013 after [1]. > > - The most popular software implementation appears to be X25 over TCP > (XOT), which is supported by Farsite and other out-of-tree stacks but > never had an implementation in mainline. > > - Most other supported HDLC hardware that we supoprt is for the ISA or > PCI buses. There are newer PCIe or USB devices, but those all require > a custom device driver and often a custom subsystem, none of which got > submitted for mainline inclusion. This includes hardware from Microgate > (SyncLink), Comtrol (RocketPort Express) and Sealevel (SeaMAC). > > - The X.25 subsystem is listed as "odd fixes", but the last reply on > the netdev mailing list from the maintainer was also in 2013[2]. > > - The HDLC subsystem itself is listed as maintained by Krzysztof Halasa, > and there were new drivers merged for SoC based devices as late as > 2016 by Zhao Qiang: Freescale/NXP QUICC Engine and Maxim ds26522. > There has not been much work on HDLC or drivers/net/wan recently, > but both developers are still responsive on the mailing list and > work on other parts of the kernel. > > Based on the above, I would conclude that X.25 can probably get moved > to staging as keeping it in the kernel seems to do more harm than good, > but HDLC below it should probably stay as there it seems there are still > users of a small subset of the mainline drivers. > > Move all of X.25 into drivers/staging for now, with a projected removal > date set for Linux-5.8. > > Cc: Eric Biggers > Cc: Andrew Hendry > Cc: linux-x25@vger.kernel.org > Cc: Kevin Curtis > Cc: "R.J.Dunlop" > Cc: Zhao Qiang > Cc: Krzysztof Halasa > Reported-by: syzbot+429c200ffc8772bfe070@syzkaller.appspotmail.com > Reported-by: syzbot+eec0c87f31a7c3b66f7b@syzkaller.appspotmail.com > Link: https://syzkaller.appspot.com/bug?id=5b0ecf0386f56be7fe7210a14d0f62df765c0c39 > Signed-off-by: Arnd Bergmann > ---- > > If anyone has different views or additional information, let us know. > > If you agree with the above, please Ack. ACK! Acked-by: Greg Kroah-Hartman