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=-5.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_RED,USER_AGENT_SANE_1 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 52B43C433DB for ; Sun, 7 Mar 2021 22:54:17 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BE47B65155 for ; Sun, 7 Mar 2021 22:54:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BE47B65155 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=armlinux.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=cLzq5Zi8qKC/RXrxNowe0JumcVyoxPXED5cun7ccPsE=; b=buka6gAQONNhDU0JAl7U8fzjg GkqhTbUeIYxwze11h3cj5cEnvCGMg2DnZI1JNXg4kYaLQeOIkJz6XKXqo0KZtwjsy2pA8+WDmImyG 0R0Xt5QBxWpQNEO36NaZCIHvvOPLDBzc+plSUjewc5M00FDt0GG4uRY/P+6xW6Bx3pitXob4PuYTN HRCzhHtV7QZsxorkCQ+F+BvYetXxA9rsx2m3F/+Usb3dnZ4uhMJc+Kp4Ks0nsvrs31KDPcAX1fIxV fdCxwQlX8gnPnqErFXjYu/QCNpVEKA/muS3oMB543gVdiQXMWXiAeWC8iG7NLMnYkFZ3rb1qozJKQ 15CqkUbPA==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lJ2Fz-00DBhe-Kz; Sun, 07 Mar 2021 22:52:15 +0000 Received: from pandora.armlinux.org.uk ([2001:4d48:ad52:32c8:5054:ff:fe00:142]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lJ2Ft-00D9A9-92 for linux-arm-kernel@lists.infradead.org; Sun, 07 Mar 2021 22:52:11 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=Ffmktd8CHukbv8ZpJIsYVvsHswFJCJz64JooEdtWqMc=; b=LtDpfo3NQ87raaFFuh8LGwjLX jU7KOHZOSalzHGG1njNTG1dNHOmaWiLLjEQeojxEvlxfXzPAs5oXCVr1wEOx52yqkRBWlNV/Uaivd 2n243gCDQEz+lBoEo/EhkJXAnC12yPywR1+oJb4LKSEqz0kpoVBU+o1AvT9FCkeTSUx8NF/ORJKM9 dB6GIcsQv5tyPljcULuUtO+PCsEGzqxQzWevrB9+Pmzrag5mMAW1B4ulB5lINm2UW8J5F2Z+9vlwh otY5xTwHH5fmNauUZ+YsxvYv9CXXMrLukKqvmvTRtkoc1I4723sjMkKYB2MWYSyT5m62sqEmH8r0e vlPubQybA==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:49836) by pandora.armlinux.org.uk with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lJ2Cl-0001gk-Lj; Sun, 07 Mar 2021 22:48:55 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1lJ2Ck-0006Zs-Nf; Sun, 07 Mar 2021 22:48:54 +0000 Date: Sun, 7 Mar 2021 22:48:54 +0000 From: Russell King - ARM Linux admin To: Ard Biesheuvel Cc: Greg Kroah-Hartman , =?utf-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= , Linus Walleij , stable@vger.kernel.org, Linux ARM Subject: Re: stable: KASan for ARM Message-ID: <20210307224854.GF1463@shell.armlinux.org.uk> References: <20210307150040.GB28240@qmqm.qmqm.pl> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210307_225209_432520_1B4B379D X-CRM114-Status: GOOD ( 25.74 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org T24gU3VuLCBNYXIgMDcsIDIwMjEgYXQgMDU6MTA6NDNQTSArMDEwMCwgQXJkIEJpZXNoZXV2ZWwg d3JvdGU6Cj4gKCsgUnVzc2VsbCkKPiAKPiBPbiBTdW4sIDcgTWFyIDIwMjEgYXQgMTY6MjEsIEdy ZWcgS3JvYWgtSGFydG1hbgo+IDxncmVna2hAbGludXhmb3VuZGF0aW9uLm9yZz4gd3JvdGU6Cj4g Pgo+ID4gT24gU3VuLCBNYXIgMDcsIDIwMjEgYXQgMDQ6MDA6NDBQTSArMDEwMCwgTWljaGHFgiBN aXJvc8WCYXcgd3JvdGU6Cj4gPiA+IERlYXIgR3JlZywKPiA+ID4KPiA+ID4gV291bGQgeW91IGNv bnNpZGVyIEtBU2FuIGZvciBBUk0gcGF0Y2hlcyBmb3IgTFRTICg1LjEwKSBrZXJuZWw/IFRob3Nl Cj4gPiA+IGFyZSA3YTFiZTMxOGY1NzkuLjQyMTAxNTcxM2IzMCBpZiBJIHVuZGVyc3RhbmQgY29y cmVjdGx5LiBUaGV5IGFyZQo+ID4gPiBub3Qgbm9ybWFsIHN0YWJsZSBtYXRlcmlhbCwgYnV0IEkg dGhpbmsgdGhleSB3aWxsIGhlbHAgdHJlbWVuZG91c2x5IGluCj4gPiA+IGRpc2NvdmVyaW5nIGtl cm5lbCBidWdzIG9uIDMyLWJpdCBBUk1zLgo+ID4KPiA+IExvb2tzIGxpa2UgYSBuZXcgZmVhdHVy ZSB0byBtZSwgcmlnaHQ/Cj4gPgo+ID4gSG93IG1hbnkgcGF0Y2hlcywgYW5kIGhhdmUgeW91IHRl c3RlZCB0aGVtPyAgSWYgc28sIHN1Ym1pdCB0aGVtIGFzIGEKPiA+IHBhdGNoIHNlcmllcyBhbmQg d2UgY2FuIHJldmlldyB0aGVtLCBidXQgaWYgdGhpcyBpcyBhIG5ldyBmZWF0dXJlLCBpdAo+ID4g ZG9lcyBub3QgbWVldCB0aGUgc3RhYmxlIGtlcm5lbCBydWxlcy4KPiA+Cj4gPiBBbmQgd2h5IG5v dCBqdXN0IHVzZSA1LjExIG9yIG5ld2VyIGZvciBkaXNjb3ZlcmluZyBrZXJuZWwgYnVncz8gIFdo eQo+ID4gZG9lcyA1LjEwIG1hdHRlciBoZXJlPwo+ID4KPiAKPiBUaGUgS0FTYW4gc3VwcG9ydCB3 YXMgcmF0aGVyIHRyaWNreSB0byBnZXQgcmlnaHQsIHNvIEkgZG9uJ3QgdGhpbmsKPiB0aGlzIGlz IHN1aXRhYmxlIGZvciBzdGFibGUuIFRoZSByYW5nZSA3YTFiZTMxOGY1NzkuLjQyMTAxNTcxM2Iz MCBpcwo+IGRlZmluaXRlbHkgbm90IGNvbXBsZXRlICh3ZSdkIG5lZWQgYXQgbGVhc3QKPiBlOWEy ZjhiNTk5ZDBiYzIyYTFiMTNlNjk1MjcyNDZhYzM5YzY5N2I0IGFuZAo+IDEwZmNlNTNjMGVmOGY2 ZTc5MTE1YzNkOWUwZDdlYTEzMzhjM2ZhMzcgYXMgd2VsbCksIGFuZCB0aGUgaW50cnVzaXZlCj4g bmF0dXJlIG9mIHRob3NlIGNoYW5nZXMgbWVhbnMgdGhleSBhcmUgZGVmaW5pdGVseSBub3QgYXBw cm9wcmlhdGUgYXMKPiBzdGFibGUgYmFja3BvcnRzLgoKSSBhZ3JlZSAtIGl0IHRvb2sgcXVpdGUg YSB3aGlsZSBmb3IgS0FTYW4gdG8gc2V0dGxlIGRvd24gLSBhbmQgb3VyIGxhc3QKaXNzdWUgd2l0 aCBLQVNhbiBjYXVzaW5nIGEgcGFuaWMgaW4gdGhlIEtwcm9iZXMgY29kZXMgd2FzIGluIEZlYnJ1 YXJ5LgpTbywgSSB0aGluayBhdCB0aGUgdmVyeSBsZWFzdCwgcmVxdWVzdGluZyB0byBiYWNrcG9y dCB0aGlzIHNvIHNvb24gaXMKcHJlbWF0dXJlLiBUaGF0IGZpeCBpcyBub3QgaW5jbHVkZWQgZXZl biBpbiB3aGF0IHlvdSBtZW50aW9uIGFib3ZlLgpNYXliZSB0aGF0IGZpeCBoYXMgYWxyZWFkeSBi ZWVuIHBpY2tlZCB1cCBpbiBzdGFibGUsIEkgZG9uJ3Qga25vdy4KClNvLCB3ZSBrbm93IHRoYXQg dGhlcmUncyBwcm9iYWJseSBtb3JlIHRvIGdldHRpbmcga3Byb2JlcyB3b3JraW5nIG9uCjMyLWJp dCBBUk0gdGhhbiBldmVuIHlvdSd2ZSBtZW50aW9uZWQgYWJvdmUuCgpJcyBpdCB3b3J0aCBiYWNr cG9ydGluZyBzdWNoIGEgbWFqb3IgZmVhdHVyZSB0byBzdGFibGUga2VybmVscz8gT3IKd291bGQg aXQgYmUgYmV0dGVyIHRvIGJhY2twb3J0IHRoZSBmaXhlcyBmb3VuZCBieSBLQVNhbiBmcm9tIGxh dGVyCmtlcm5lbHM/IE15IGZlZWxpbmcgaXMgdGhlIGxhdHRlciBpcyB0aGUgYmV0dGVyIGFsbCBy b3VuZCBhcHByb2FjaC4KCi0tIApSTUsncyBQYXRjaCBzeXN0ZW06IGh0dHBzOi8vd3d3LmFybWxp bnV4Lm9yZy51ay9kZXZlbG9wZXIvcGF0Y2hlcy8KRlRUUCBpcyBoZXJlISA0ME1icHMgZG93biAx ME1icHMgdXAuIERlY2VudCBjb25uZWN0aXZpdHkgYXQgbGFzdCEKCl9fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fCmxpbnV4LWFybS1rZXJuZWwgbWFpbGluZyBs aXN0CmxpbnV4LWFybS1rZXJuZWxAbGlzdHMuaW5mcmFkZWFkLm9yZwpodHRwOi8vbGlzdHMuaW5m cmFkZWFkLm9yZy9tYWlsbWFuL2xpc3RpbmZvL2xpbnV4LWFybS1rZXJuZWwK 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=-5.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_RED,USER_AGENT_SANE_1 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 AF22EC433DB for ; Sun, 7 Mar 2021 22:49:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 67DC66515E for ; Sun, 7 Mar 2021 22:49:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230211AbhCGWtA (ORCPT ); Sun, 7 Mar 2021 17:49:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52792 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229740AbhCGWtA (ORCPT ); Sun, 7 Mar 2021 17:49:00 -0500 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D216EC06174A for ; Sun, 7 Mar 2021 14:48:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=Ffmktd8CHukbv8ZpJIsYVvsHswFJCJz64JooEdtWqMc=; b=LtDpfo3NQ87raaFFuh8LGwjLX jU7KOHZOSalzHGG1njNTG1dNHOmaWiLLjEQeojxEvlxfXzPAs5oXCVr1wEOx52yqkRBWlNV/Uaivd 2n243gCDQEz+lBoEo/EhkJXAnC12yPywR1+oJb4LKSEqz0kpoVBU+o1AvT9FCkeTSUx8NF/ORJKM9 dB6GIcsQv5tyPljcULuUtO+PCsEGzqxQzWevrB9+Pmzrag5mMAW1B4ulB5lINm2UW8J5F2Z+9vlwh otY5xTwHH5fmNauUZ+YsxvYv9CXXMrLukKqvmvTRtkoc1I4723sjMkKYB2MWYSyT5m62sqEmH8r0e vlPubQybA==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:49836) by pandora.armlinux.org.uk with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lJ2Cl-0001gk-Lj; Sun, 07 Mar 2021 22:48:55 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1lJ2Ck-0006Zs-Nf; Sun, 07 Mar 2021 22:48:54 +0000 Date: Sun, 7 Mar 2021 22:48:54 +0000 From: Russell King - ARM Linux admin To: Ard Biesheuvel Cc: Greg Kroah-Hartman , =?utf-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= , Linus Walleij , stable@vger.kernel.org, Linux ARM Subject: Re: stable: KASan for ARM Message-ID: <20210307224854.GF1463@shell.armlinux.org.uk> References: <20210307150040.GB28240@qmqm.qmqm.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: Russell King - ARM Linux admin Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Sun, Mar 07, 2021 at 05:10:43PM +0100, Ard Biesheuvel wrote: > (+ Russell) > > On Sun, 7 Mar 2021 at 16:21, Greg Kroah-Hartman > wrote: > > > > On Sun, Mar 07, 2021 at 04:00:40PM +0100, Michał Mirosław wrote: > > > Dear Greg, > > > > > > Would you consider KASan for ARM patches for LTS (5.10) kernel? Those > > > are 7a1be318f579..421015713b30 if I understand correctly. They are > > > not normal stable material, but I think they will help tremendously in > > > discovering kernel bugs on 32-bit ARMs. > > > > Looks like a new feature to me, right? > > > > How many patches, and have you tested them? If so, submit them as a > > patch series and we can review them, but if this is a new feature, it > > does not meet the stable kernel rules. > > > > And why not just use 5.11 or newer for discovering kernel bugs? Why > > does 5.10 matter here? > > > > The KASan support was rather tricky to get right, so I don't think > this is suitable for stable. The range 7a1be318f579..421015713b30 is > definitely not complete (we'd need at least > e9a2f8b599d0bc22a1b13e69527246ac39c697b4 and > 10fce53c0ef8f6e79115c3d9e0d7ea1338c3fa37 as well), and the intrusive > nature of those changes means they are definitely not appropriate as > stable backports. I agree - it took quite a while for KASan to settle down - and our last issue with KASan causing a panic in the Kprobes codes was in February. So, I think at the very least, requesting to backport this so soon is premature. That fix is not included even in what you mention above. Maybe that fix has already been picked up in stable, I don't know. So, we know that there's probably more to getting kprobes working on 32-bit ARM than even you've mentioned above. Is it worth backporting such a major feature to stable kernels? Or would it be better to backport the fixes found by KASan from later kernels? My feeling is the latter is the better all round approach. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!