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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 223A3C433F5 for ; Wed, 29 Dec 2021 13:31:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230464AbhL2Nbd (ORCPT ); Wed, 29 Dec 2021 08:31:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236926AbhL2Nba (ORCPT ); Wed, 29 Dec 2021 08:31:30 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EF619C06175C for ; Wed, 29 Dec 2021 05:31:07 -0800 (PST) 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 97819614C5 for ; Wed, 29 Dec 2021 13:31:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6AB3EC36AE9; Wed, 29 Dec 2021 13:31:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1640784667; bh=wEIrM3KVXtjiaYLb3zF9Vz51LRh7VeVJe3NjXJa42i0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=h9G+nJ+A4mltp1GcKNN89fhqLD6OkhpceFQEwoIJ6lzGdSlqEheXG2agCw4hY5rBb v3srROBl+eCTZ6bg/H4Jwlw47+jrryUKe5d6eDlbX8DM748pnc/K7pSjV1iizxEhkS Tj/pUCY2cmNWffhY1YI/bY3hYoByBMVfjbsd1JNU= Date: Wed, 29 Dec 2021 14:31:04 +0100 From: Greg Kroah-Hartman To: Shile Zhang Cc: David Airlie , Daniel Vetter , Wen Kang , stable@vger.kernel.org Subject: Re: [PATCH 5.10.y] drm/cirrus: fix a NULL vs IS_ERR() checks Message-ID: References: <20211228132556.108711-1-shile.zhang@linux.alibaba.com> <1cc25ebe-2c68-458b-15a2-fc4c80ba2054@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Wed, Dec 29, 2021 at 08:48:53AM +0800, Shile Zhang wrote: > > > On 2021/12/28 22:39, Greg Kroah-Hartman wrote: > > On Tue, Dec 28, 2021 at 10:19:30PM +0800, Shile Zhang wrote: > > > > > > > > > On 2021/12/28 22:05, Greg Kroah-Hartman wrote: > > > > On Tue, Dec 28, 2021 at 09:56:25PM +0800, Shile Zhang wrote: > > > > > > > > > > > > > > > On 2021/12/28 21:51, Greg Kroah-Hartman wrote: > > > > > > On Tue, Dec 28, 2021 at 09:25:56PM +0800, Shile Zhang wrote: > > > > > > > The function drm_gem_shmem_vmap can returns error pointers as well, > > > > > > > which could cause following kernel crash: > > > > > > > > > > > > > > BUG: unable to handle page fault for address: fffffffffffffffc > > > > > > > PGD 1426a12067 P4D 1426a12067 PUD 1426a14067 PMD 0 > > > > > > > Oops: 0000 [#1] SMP NOPTI > > > > > > > CPU: 12 PID: 3598532 Comm: stress-ng Kdump: loaded Not tainted 5.10.50.x86_64 #1 > > > > > > > ... > > > > > > > RIP: 0010:memcpy_toio+0x23/0x50 > > > > > > > Code: 00 00 00 00 0f 1f 00 0f 1f 44 00 00 48 85 d2 74 28 40 f6 c7 01 75 2b 48 83 fa 01 76 06 40 f6 c7 02 75 17 48 89 d1 48 c1 e9 02 a5 f6 c2 02 74 02 66 a5 f6 c2 01 74 01 a4 c3 66 a5 48 83 ea 02 > > > > > > > RSP: 0018:ffffafbf8a203c68 EFLAGS: 00010216 > > > > > > > RAX: 0000000000000000 RBX: fffffffffffffffc RCX: 0000000000000200 > > > > > > > RDX: 0000000000000800 RSI: fffffffffffffffc RDI: ffffafbf82000000 > > > > > > > RBP: ffffafbf82000000 R08: 0000000000000002 R09: 0000000000000000 > > > > > > > R10: 00000000000002b5 R11: 0000000000000000 R12: 0000000000000800 > > > > > > > R13: ffff8a6801099300 R14: 0000000000000001 R15: 0000000000000300 > > > > > > > FS: 00007f4a6bc5f740(0000) GS:ffff8a8641900000(0000) knlGS:0000000000000000 > > > > > > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > > > > > > CR2: fffffffffffffffc CR3: 00000016d3874001 CR4: 00000000003606e0 > > > > > > > Call Trace: > > > > > > > drm_fb_memcpy_dstclip+0x5e/0x80 [drm_kms_helper] > > > > > > > cirrus_fb_blit_rect.isra.0+0xb7/0xe0 [cirrus] > > > > > > > cirrus_pipe_update+0x9f/0xa8 [cirrus] > > > > > > > drm_atomic_helper_commit_planes+0xb8/0x220 [drm_kms_helper] > > > > > > > drm_atomic_helper_commit_tail+0x42/0x80 [drm_kms_helper] > > > > > > > commit_tail+0xce/0x130 [drm_kms_helper] > > > > > > > drm_atomic_helper_commit+0x113/0x140 [drm_kms_helper] > > > > > > > drm_client_modeset_commit_atomic+0x1c4/0x200 [drm] > > > > > > > drm_client_modeset_commit_locked+0x53/0x80 [drm] > > > > > > > drm_client_modeset_commit+0x24/0x40 [drm] > > > > > > > drm_fbdev_client_restore+0x48/0x85 [drm_kms_helper] > > > > > > > drm_client_dev_restore+0x64/0xb0 [drm] > > > > > > > drm_release+0xf2/0x110 [drm] > > > > > > > __fput+0x96/0x240 > > > > > > > task_work_run+0x5c/0x90 > > > > > > > exit_to_user_mode_loop+0xce/0xd0 > > > > > > > exit_to_user_mode_prepare+0x6a/0x70 > > > > > > > syscall_exit_to_user_mode+0x12/0x40 > > > > > > > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > > > > > > RIP: 0033:0x7f4a6bd82c2b > > > > > > > > > > > > > > Fixes: ab3e023b1b4c9 ("drm/cirrus: rewrite and modernize driver.") > > > > > > > > > > > > > > CC: stable@vger.kernel.org > > > > > > > Reported-by: Wen Kang > > > > > > > Signed-off-by: Shile Zhang > > > > > > > --- > > > > > > > drivers/gpu/drm/tiny/cirrus.c | 2 +- > > > > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > > > > > What is the git commit id of this patch in Linus's tree? > > > > > > > > > > Sorry, I checked that this issue seems fixed by the improvement in following > > > > > series: > > > > > https://patchwork.freedesktop.org/series/82217/ > > > > > > > > I do not understand, that is a huge patch series. What individual > > > > commit in Linus's tree resolves this? > > > > > > Sorry, > > > 1. This crash only happened in 5.10.y tree now, which fixed in Linus's tree > > > by refactoring in above huge series. > > > > Which specific patch resolved the issue? > > > > > 2. It's hard to get the individual commit to fix this issue from that > > > series. So I try to send this simple fix help to fix only for 5.10.y, which > > > is needless to Linus's tree. > > > > 'git bisect' should be able to help you out. > > Thanks for your guidance! > > > > > > 3. If this patch is not OK for stable tree, Could you please help to > > > backport the correct fix from Linus's tree in next version of 5.10.y? > > > > If you can provide the commit id of the fix, sure. > > Thanks! > I think it is this commit, which refactor the drm_gem_shmem_vmap makes the > pointer returned by new added parameter. > https://github.com/torvalds/linux/commit/49a3f51dfeeecb52c5aa28c5cb9592fe5e39bf95 Have you tested it to be sure? If so, can you please provide a backported version that works? As-is, it does not apply at all. Note, if this is to bit of a change for a stable tree (and I think it is), your original patch might be correct, but I need some acks from the subsystem maintainers before I can take such a thing. I also need a lot of documentation in the changelog text about why this is a 5.10-only thing. thanks, greg k-h