From patchwork Tue Sep 8 20:41:15 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Grazvydas Ignotas X-Patchwork-Id: 7143201 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 18A3B9F32B for ; Tue, 8 Sep 2015 20:44:04 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2D24120812 for ; Tue, 8 Sep 2015 20:44:03 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 41984207B4 for ; Tue, 8 Sep 2015 20:44:02 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZZPi1-0007ey-Nx; Tue, 08 Sep 2015 20:41:41 +0000 Received: from mail-yk0-x236.google.com ([2607:f8b0:4002:c07::236]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZZPhz-0007Rq-8u for linux-arm-kernel@lists.infradead.org; Tue, 08 Sep 2015 20:41:40 +0000 Received: by ykei199 with SMTP id i199so138450302yke.0 for ; Tue, 08 Sep 2015 13:41:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; bh=AC+wPMvNy++HXWXUnVucQMm/fIHp4jW++5WsnX1Fm9s=; b=aPeh5O61uenlaoB9/t8ZyOdtq+3IHXTb1E6ep+j8OPBiVRu8Yi9CD/UAvydOMk5zRL FqeN4MeHLpg9Lj1neG8Zr6w38LZjbKdA8Kp+Q0OfRr1NsczrBe3k/x3OZhQaNYp7m87a 2l3KpMsEQnAVhPpma2+swvDWj+qA/aO5+Z8faxM1+mnBKMYZcIdlwxYLWfcAITwgW2j7 XO5HW+MO5LO20UjZxaRbjOLMp7Zi90BJPv1QY3mNFPSrSZdOkzl8rlY1qON6rZ4sZMwj 5dGynMcG1Dc3AXSm1YpMEvgyGbTWHVA5bZrjCLmTwAAHsy7gEmqCw55SUKd73G6Xg52i WnHQ== MIME-Version: 1.0 X-Received: by 10.170.222.212 with SMTP id o203mr31969268ykf.73.1441744875961; Tue, 08 Sep 2015 13:41:15 -0700 (PDT) Received: by 10.13.238.193 with HTTP; Tue, 8 Sep 2015 13:41:15 -0700 (PDT) In-Reply-To: <20150908143810.GD4215@atomide.com> References: <20150908143810.GD4215@atomide.com> Date: Tue, 8 Sep 2015 22:41:15 +0200 Message-ID: Subject: Re: mysterious crashes on OMAP5 uevm From: Grazvydas Ignotas To: Tony Lindgren X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150908_134139_519682_BB396260 X-CRM114-Status: GOOD ( 19.37 ) X-Spam-Score: -2.7 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Nishanth Menon , "Dr. H. Nikolaus Schaller" , "linux-omap@vger.kernel.org" , Russell King - ARM Linux , "linux-arm-kernel@lists.infradead.org" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.1 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_MED, T_DKIM_INVALID, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On Tue, Sep 8, 2015 at 4:38 PM, Tony Lindgren wrote: > * Grazvydas Ignotas [150908 05:50]: >> Hi, >> >> this is a longstanding problem I'm seeing since the very beginning, >> which was around 3.12 or so (when I've first got the hardware) and it >> seems 4.2 is affected by it still. Basically what happens is Xorg >> randomly segfaults at some "impossible" location. I don't have the >> details at the moment (could get them is needed), but from what I >> examined with gdb some time ago the situation did not make any sense. >> >> There are 2 workarounds that I know which make the problem go away >> (one is enough): >> - recompile Xorg with -marm (I'm using Debian armhf so it's thumb2 by default) >> - disable ARCH_MULTI_V6 in the kernel config >> >> Because of the above workarounds I have forgotten about it several >> times, but it regularly comes back and bites again. It would look like >> some missing erratum workaround, but I have all of them enabled in the >> kernel. >> >> Does anyone know about this? Perhaps some missing erratum workaround >> in the bootloader? u-boot isn't too old here (2015.07). > > Seems like some incorrect handling with CONFIG_CPU_V6 compiled in.. > Maybe try to narrow it down by commenting out some CONFIG_CPU_V6 and > __LINUX_ARM_ARCH__ = 6 ifdefs in the git grep CONFIG_CPU_V6 > places ignoring uncompress and davinci code. ok with that it was quite easy to find. On a kernel with ARCH_MULTI_V6 disabled, it is enough to just do this: ... and the problem appears, so I guess this needs some real multiplatform handling,. > Do you have some easy way to reproduce this issue? Just moving a browser window around with mouse usually triggers it within a minute. > > Regards, > > Tony GraÅžvydas --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -340,13 +340,13 @@ setup_return(struct pt_regs *regs, struct ksignal *ksig, /* * The LSB of the handler determines if we're going to * be using THUMB or ARM mode for this signal handler. */ thumb = handler & 1; -#if __LINUX_ARM_ARCH__ >= 7 +#if 0 //__LINUX_ARM_ARCH__ >= 7 /* * Clear the If-Then Thumb-2 execution state * ARM spec requires this to be all 000s in ARM mode * Snapdragon S4/Krait misbehaves on a Thumb=>ARM * signal transition without this. */