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 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 25A2CC433F5 for ; Mon, 11 Apr 2022 08:28:26 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 5F4A610E38F; Mon, 11 Apr 2022 08:28:25 +0000 (UTC) Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by gabe.freedesktop.org (Postfix) with ESMTPS id 139C710E38F for ; Mon, 11 Apr 2022 08:28:24 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2FB6E614CF; Mon, 11 Apr 2022 08:28:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 38CDEC385A4; Mon, 11 Apr 2022 08:28:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649665702; bh=Hhy5UMcIA35ZHVndOjsEty8QreQ6afNmpjXCNOu+/5U=; h=Subject:To:Cc:From:Date:From; b=a9qx+EGt5XI0UJ1Dh904kRjP9Kdc2KI+EUV6NAgih0w9XQ4hIxnBp7ARDXuR1VL6U PS60RCvHa3gajofIYgQo2Y5hV6usROMZ+R11sbE8aI8eh6G8jdA+J11MXEmEDhP4j7 FpxgX2JB8qSBqnOHn8Su7Vc7Tclrh2smI8AhlnV0= Subject: Patch "fbdev: Fix unregistering of framebuffers without device" has been added to the 5.16-stable tree To: alexander.deucher@amd.com, daniel.vetter@ffwll.ch, deller@gmx.de, dri-devel@lists.freedesktop.org, gregkh@linuxfoundation.org, hdegoede@redhat.com, javierm@redhat.com, linux@roeck-us.net, penguin-kernel@i-love.sakura.ne.jp, sam@ravnborg.org, sudip.mukherjee@codethink.co.uk, sudipm.mukherjee@gmail.com, thunder.leizhen@huawei.com, tzimmermann@suse.de, willy@infradead.org, xiyuyang19@fudan.edu.cn, zackr@vmware.com, zheyuma97@gmail.com From: Date: Mon, 11 Apr 2022 10:27:34 +0200 Message-ID: <1649665654151109@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit X-stable: commit X-Patchwork-Hint: ignore X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: stable-commits@vger.kernel.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" This is a note to let you know that I've just added the patch titled fbdev: Fix unregistering of framebuffers without device to the 5.16-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: fbdev-fix-unregistering-of-framebuffers-without-device.patch and it can be found in the queue-5.16 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >From 0f525289ff0ddeb380813bd81e0f9bdaaa1c9078 Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Mon, 4 Apr 2022 21:44:02 +0200 Subject: fbdev: Fix unregistering of framebuffers without device From: Thomas Zimmermann commit 0f525289ff0ddeb380813bd81e0f9bdaaa1c9078 upstream. OF framebuffers do not have an underlying device in the Linux device hierarchy. Do a regular unregister call instead of hot unplugging such a non-existing device. Fixes a NULL dereference. An example error message on ppc64le is shown below. BUG: Kernel NULL pointer dereference on read at 0x00000060 Faulting instruction address: 0xc00000000080dfa4 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries [...] CPU: 2 PID: 139 Comm: systemd-udevd Not tainted 5.17.0-ae085d7f9365 #1 NIP: c00000000080dfa4 LR: c00000000080df9c CTR: c000000000797430 REGS: c000000004132fe0 TRAP: 0300 Not tainted (5.17.0-ae085d7f9365) MSR: 8000000002009033 CR: 28228282 XER: 20000000 CFAR: c00000000000c80c DAR: 0000000000000060 DSISR: 40000000 IRQMASK: 0 GPR00: c00000000080df9c c000000004133280 c00000000169d200 0000000000000029 GPR04: 00000000ffffefff c000000004132f90 c000000004132f88 0000000000000000 GPR08: c0000000015658f8 c0000000015cd200 c0000000014f57d0 0000000048228283 GPR12: 0000000000000000 c00000003fffe300 0000000020000000 0000000000000000 GPR16: 0000000000000000 0000000113fc4a40 0000000000000005 0000000113fcfb80 GPR20: 000001000f7283b0 0000000000000000 c000000000e4a588 c000000000e4a5b0 GPR24: 0000000000000001 00000000000a0000 c008000000db0168 c0000000021f6ec0 GPR28: c0000000016d65a8 c000000004b36460 0000000000000000 c0000000016d64b0 NIP [c00000000080dfa4] do_remove_conflicting_framebuffers+0x184/0x1d0 [c000000004133280] [c00000000080df9c] do_remove_conflicting_framebuffers+0x17c/0x1d0 (unreliable) [c000000004133350] [c00000000080e4d0] remove_conflicting_framebuffers+0x60/0x150 [c0000000041333a0] [c00000000080e6f4] remove_conflicting_pci_framebuffers+0x134/0x1b0 [c000000004133450] [c008000000e70438] drm_aperture_remove_conflicting_pci_framebuffers+0x90/0x100 [drm] [c000000004133490] [c008000000da0ce4] bochs_pci_probe+0x6c/0xa64 [bochs] [...] [c000000004133db0] [c00000000002aaa0] system_call_exception+0x170/0x2d0 [c000000004133e10] [c00000000000c3cc] system_call_common+0xec/0x250 The bug [1] was introduced by commit 27599aacbaef ("fbdev: Hot-unplug firmware fb devices on forced removal"). Most firmware framebuffers have an underlying platform device, which can be hot-unplugged before loading the native graphics driver. OF framebuffers do not (yet) have that device. Fix the code by unregistering the framebuffer as before without a hot unplug. Tested with 5.17 on qemu ppc64le emulation. Signed-off-by: Thomas Zimmermann Fixes: 27599aacbaef ("fbdev: Hot-unplug firmware fb devices on forced removal") Reported-by: Sudip Mukherjee Reviewed-by: Daniel Vetter Reviewed-by: Javier Martinez Canillas Tested-by: Sudip Mukherjee Cc: Zack Rusin Cc: Javier Martinez Canillas Cc: Hans de Goede Cc: stable@vger.kernel.org # v5.11+ Cc: Helge Deller Cc: Daniel Vetter Cc: Sam Ravnborg Cc: Zheyu Ma Cc: Xiyu Yang Cc: Zhen Lei Cc: Matthew Wilcox Cc: Alex Deucher Cc: Tetsuo Handa Cc: Guenter Roeck Cc: linux-fbdev@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Link: https://lore.kernel.org/all/YkHXO6LGHAN0p1pq@debian/ # [1] Link: https://patchwork.freedesktop.org/patch/msgid/20220404194402.29974-1-tzimmermann@suse.de Signed-off-by: Greg Kroah-Hartman --- drivers/video/fbdev/core/fbmem.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -1581,7 +1581,14 @@ static void do_remove_conflicting_frameb * If it's not a platform device, at least print a warning. A * fix would add code to remove the device from the system. */ - if (dev_is_platform(device)) { + if (!device) { + /* TODO: Represent each OF framebuffer as its own + * device in the device hierarchy. For now, offb + * doesn't have such a device, so unregister the + * framebuffer as before without warning. + */ + do_unregister_framebuffer(registered_fb[i]); + } else if (dev_is_platform(device)) { registered_fb[i]->forced_out = true; platform_device_unregister(to_platform_device(device)); } else { Patches currently in stable-queue which might be from tzimmermann@suse.de are queue-5.16/fbdev-fix-unregistering-of-framebuffers-without-device.patch