From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752795AbcHLRKf (ORCPT ); Fri, 12 Aug 2016 13:10:35 -0400 Received: from foss.arm.com ([217.140.101.70]:60482 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752680AbcHLRKe (ORCPT ); Fri, 12 Aug 2016 13:10:34 -0400 Date: Fri, 12 Aug 2016 18:10:30 +0100 From: Catalin Marinas To: Laura Abbott Cc: Mark Rutland , Will Deacon , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Ard Biesheuvel Subject: Re: [PATCHv5] arm64: Handle el1 synchronous instruction aborts cleanly Message-ID: <20160812171030.GK12939@e104818-lin.cambridge.arm.com> References: <1470792326-565-1-git-send-email-labbott@redhat.com> <20160812170508.GI12939@e104818-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160812170508.GI12939@e104818-lin.cambridge.arm.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 12, 2016 at 06:05:09PM +0100, Catalin Marinas wrote: > On Tue, Aug 09, 2016 at 06:25:26PM -0700, Laura Abbott wrote: > > Executing from a non-executable area gives an ugly message: > > > > lkdtm: Performing direct entry EXEC_RODATA > > lkdtm: attempting ok execution at ffff0000084c0e08 > > lkdtm: attempting bad execution at ffff000008880700 > > Bad mode in Synchronous Abort handler detected on CPU2, code 0x8400000e -- IABT (current EL) > > CPU: 2 PID: 998 Comm: sh Not tainted 4.7.0-rc2+ #13 > > Hardware name: linux,dummy-virt (DT) > > task: ffff800077e35780 ti: ffff800077970000 task.ti: ffff800077970000 > > PC is at lkdtm_rodata_do_nothing+0x0/0x8 > > LR is at execute_location+0x74/0x88 > > > > The 'IABT (current EL)' indicates the error but it's a bit cryptic > > without knowledge of the ARM ARM. There is also no indication of the > > specific address which triggered the fault. The increase in kernel > > page permissions makes hitting this case more likely as well. > > Handling the case in the vectors gives a much more familiar looking > > error message: > > > > lkdtm: Performing direct entry EXEC_RODATA > > lkdtm: attempting ok execution at ffff0000084c0840 > > lkdtm: attempting bad execution at ffff000008880680 > > Unable to handle kernel paging request at virtual address ffff000008880680 > > pgd = ffff8000089b2000 > > [ffff000008880680] *pgd=00000000489b4003, *pud=0000000048904003, *pmd=0000000000000000 > > Internal error: Oops: 8400000e [#1] PREEMPT SMP > > Modules linked in: > > CPU: 1 PID: 997 Comm: sh Not tainted 4.7.0-rc1+ #24 > > Hardware name: linux,dummy-virt (DT) > > task: ffff800077f9f080 ti: ffff800008a1c000 task.ti: ffff800008a1c000 > > PC is at lkdtm_rodata_do_nothing+0x0/0x8 > > LR is at execute_location+0x74/0x88 > > > > Acked-by: Mark Rutland > > Signed-off-by: Laura Abbott > > Applied. Thanks. Actually, Will queued it already for 4.9. -- Catalin