From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Subject: Re: [offlist] Re: Crash in netlink/sk_filter_trim_cap on ARMv7 on 4.18rc1 Date: Fri, 17 Aug 2018 17:17:43 +0100 Message-ID: <20180817161743.GX30658@n2100.armlinux.org.uk> References: <7ff516fd-1d01-4d7a-1d5d-b58932c0c69d@gmail.com> <20180816203515.GA7688@torres.zugschlus.de> <20180816225844.GW30658@n2100.armlinux.org.uk> <1c2218cb-63bf-1528-6156-8ce93f46169c@iogearbox.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Peter Robinson , Marc Haber , linux-arm-kernel@lists.infradead.org, netdev@vger.kernel.org, labbott@redhat.com, Eric Dumazet To: Daniel Borkmann Return-path: Received: from pandora.armlinux.org.uk ([78.32.30.218]:39022 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727447AbeHQTVw (ORCPT ); Fri, 17 Aug 2018 15:21:52 -0400 Content-Disposition: inline In-Reply-To: <1c2218cb-63bf-1528-6156-8ce93f46169c@iogearbox.net> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, Aug 17, 2018 at 02:40:19PM +0200, Daniel Borkmann wrote: > I'd have one potential bug suspicion, for the 4.18 one you were trying, > could you run with the below patch to see whether it would help? I think this is almost certainly the problem - looking at the history, it seems that the "-4" was assumed to be part of the scratch stuff in commit 38ca93060163 ("bpf, arm32: save 4 bytes of unneeded stack space") but it isn't - it's because "off" of zero refers to the top word in the stack (iow at STACK_SIZE-4). -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 13.8Mbps down 630kbps up According to speedtest.net: 13Mbps down 490kbps up