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=-3.0 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 143D2C07E99 for ; Fri, 9 Jul 2021 15:45:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E8207613BC for ; Fri, 9 Jul 2021 15:45:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232385AbhGIPsa (ORCPT ); Fri, 9 Jul 2021 11:48:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49546 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232269AbhGIPs3 (ORCPT ); Fri, 9 Jul 2021 11:48:29 -0400 Received: from mail-pj1-x1036.google.com (mail-pj1-x1036.google.com [IPv6:2607:f8b0:4864:20::1036]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2B9FBC0613DD for ; Fri, 9 Jul 2021 08:45:46 -0700 (PDT) Received: by mail-pj1-x1036.google.com with SMTP id p4-20020a17090a9304b029016f3020d867so6283888pjo.3 for ; Fri, 09 Jul 2021 08:45:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Xr/oo6QaKEF3yyBzroogqbeO+TEDdTjBQ/ohjUC5aco=; b=gNm9KR7Nl8b9kI9wKWmASc8pm+nB7atspkpJFn7eECRe/lnLCs4xSNPxz58yuIa1OK R/vZghjGU4MRZtmnPjYdWXKqguGp+KH3Zx9PvkHubZupsYJxxK1hWxywGPCbQsyJwaM3 xkym/IhEZz/64BDNO0BDoiNpBDquYRtarrFQ2VI4LLDwhpkzZEtrMRK2JurOaADNG+o0 KBm+6blpXBJT8pwmAbekJEnr0U7c1mFvv7whPja26P2EJLmbsX3mCvBkFN7JR71p6Jw7 oaazMaMkY6Rw8uENKdeQBZ6MRuK+UHBaKg7tPQ8qGcLTrc/rmn2ropvAlqS6Al6OeEmk n1cw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Xr/oo6QaKEF3yyBzroogqbeO+TEDdTjBQ/ohjUC5aco=; b=I1K1Cu1wBYPwwgOEAnsB5BNjmjrcmXrwkxm+cU116VhnTNdn3W5G8qNqevYaCZflDI 5NYwF/jZlcLDJl4DVTRGpBkA4ihFrxiiHZuMctbMazx4GOlA5pp23BRpFH4jvEFGExdY dgYbomlB47tsDl1yDV2fMXSjnFCPX1P1o1+mYgWATHZQJkIKOi4pGJkhRiK47FHI+h7e cZJAScMtVfTHZ0ZJaMJgV4Z2LB6H4714R7fhiI2lyhiHUdDrluxxFCb302VmQX7dS94Z JXW2WaPNoRxYLX9E7av4iS0BCpauasxwOzo8TK2iM4XXPh9aWMiVZDQnLFz319ieuuTp M7gQ== X-Gm-Message-State: AOAM531fwYm9cqUjIzaUh9H8GZhYNUyy/y4yoFdeXZ0HP4bg3PcD4ioc 8s9QiOpsp0MUXdKB8CKCERiLcAyICE5u28INUECSXLvaWBjudA== X-Google-Smtp-Source: ABdhPJzNrUv4fPbngocprXlQfxtuH19GJRjFf7mXutAxJzFikk7L3/9XR5BkuWb3UkVh+I09qpS91rNkXCt+nPshsFc= X-Received: by 2002:a17:90b:3647:: with SMTP id nh7mr4697326pjb.228.1625845545524; Fri, 09 Jul 2021 08:45:45 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Andy Shevchenko Date: Fri, 9 Jul 2021 18:45:06 +0300 Message-ID: Subject: Re: parallel panel display stopped working To: Linux Kernel Mailing List , Miguel Ojeda , Lars Poeschel Cc: Andy Shevchenko , Geert Uytterhoeven Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 9, 2021 at 5:54 PM Andy Shevchenko wrote: > > On Fri, Jul 9, 2021 at 5:40 PM Andy Shevchenko > wrote: > > > > Parallel (4 bits) panel display stopped working. > > I have no time right now to bisect but I have noticed there was quite > > a pile of patches from Lars to the driver recently (yeah, it seems for > > a few months I haven't run my tests against the AUX display driver). > > > > I believe the issue is there somewhere. > > > > Moreover on the removal I have got an oops > > > > [ 218.825445] kernel tried to execute NX-protected page - exploit > > attempt? (uid: 0) > > [ 218.832965] BUG: unable to handle page fault for address: ffff8f8f06559dc0 > > [ 218.839863] #PF: supervisor instruction fetch in kernel mode > > [ 218.845540] #PF: error_code(0x0011) - permissions violation > > [ 218.851132] PGD e601067 P4D e601067 PUD e602067 PMD 645a063 PTE > > 8000000006559063 > > [ 218.858587] Oops: 0011 [#1] SMP PTI > > [ 218.862099] CPU: 0 PID: 7 Comm: kworker/u4:0 Tainted: G C > > 5.13.0+ #23 > > [ 218.869870] Hardware name: Intel Corporation Merrifield/BODEGA BAY, > > BIOS 542 2015.01.21:18.19.48 > > [ 218.878681] Workqueue: kacpi_hotplug acpi_device_del_work_fn > > [ 218.884380] RIP: 0010:0xffff8f8f06559dc0 > > [ 218.888328] Code: ff ff d2 2b 21 8c ff ff ff ff 08 00 00 00 00 00 > > 00 00 78 34 fa 02 8f 8f ff ff 00 00 00 00 00 > > 00 00 00 00 00 00 00 00 00 00 00 <72> 65 67 75 6c 61 74 6f 72 3a 72 65 > > 67 75 6c 61 74 6f 72 2e 30 2d > > [ 218.907138] RSP: 0000:ffffad36c0043c90 EFLAGS: 00010246 > > [ 218.912387] RAX: ffff8f8f06559dc0 RBX: ffff8f8f062cbc00 RCX: ffff8f8f01239fc8 > > [ 218.919542] RDX: 000000002a3cccf8 RSI: 0000000000000001 RDI: ffff8f8f06559480 > > [ 218.926701] RBP: ffffffffc037e279 R08: 00000000d5832520 R09: 0000000000000001 > > [ 218.933856] R10: 0000000000000000 R11: 0000000000000001 R12: ffff8f8f062cbc00 > > [ 218.941010] R13: ffffffffc038e028 R14: ffffffff8c5e0b60 R15: 00000000fffffffd > > [ 218.948166] FS: 0000000000000000(0000) GS:ffff8f8f3e200000(0000) > > knlGS:0000000000000000 > > [ 218.956286] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > [ 218.962053] CR2: ffff8f8f06559dc0 CR3: 0000000002ef4000 CR4: 00000000001006f0 > > [ 218.969208] Call Trace: > > [ 218.971678] ? hd44780_common_clear_display+0x17/0x30 [hd44780_common] > > [ 218.978252] ? charlcd_write_char+0x21a/0x810 [charlcd] > > [ 218.983519] ? charlcd_puts+0x30/0x60 [charlcd] > > [ 218.988083] ? charlcd_unregister+0x24/0x70 [charlcd] > > [ 218.993167] ? hd44780_remove+0x1e/0x30 [hd44780] > > [ 218.997901] ? platform_remove+0x1f/0x40 > > ... > > > > Just for your information and with hope that somebody may test and/or > > reproduce this and fix it. Later on I might find time to bisect the > > other issue I mentioned above. > > For time being confirmed the following: > 1. a2060f288e15 ("auxdisplay: Call charlcd_backlight in place") has a > remove bug (above), while panel works > 2. 66ce7d5c1e12 ("auxdisplay: Use an enum for charlcd backlight on/off > ops") everything works as expected > > So, the oops introduced in between those two. The culprit (*) is 01ec46dfa633 ("auxdisplay: Move init_display to hd44780_common"). *) Obviously it's not. It reveals the design issue on how the modules were split. How this had been tested if tested at all? P.S. If we don't get a fix in time, I will ask Miguel to revert the entire pile. -- With Best Regards, Andy Shevchenko