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=-4.0 required=3.0 tests=BAYES_00,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 5B7FAC433DF for ; Sun, 26 Jul 2020 18:41:00 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 2DDD4206E3 for ; Sun, 26 Jul 2020 18:40:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2DDD4206E3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=bugzilla.kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 5F43889FD1; Sun, 26 Jul 2020 18:40:58 +0000 (UTC) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8411789F19 for ; Sun, 26 Jul 2020 18:40:57 +0000 (UTC) From: bugzilla-daemon@bugzilla.kernel.org To: dri-devel@lists.freedesktop.org Subject: [Bug 207383] [Regression] 5.7 amdgpu/polaris11 gpf: amdgpu_atomic_commit_tail Date: Sun, 26 Jul 2020 18:40:55 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: AssignedTo drivers_video-dri@kernel-bugs.osdl.org X-Bugzilla-Product: Drivers X-Bugzilla-Component: Video(DRI - non Intel) X-Bugzilla-Version: 2.5 X-Bugzilla-Keywords: X-Bugzilla-Severity: blocking X-Bugzilla-Who: nicholas.kazlauskas@amd.com X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P1 X-Bugzilla-Assigned-To: drivers_video-dri@kernel-bugs.osdl.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: attachments.created Message-ID: In-Reply-To: References: X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated MIME-Version: 1.0 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" https://bugzilla.kernel.org/show_bug.cgi?id=207383 --- Comment #95 from Nicholas Kazlauskas (nicholas.kazlauskas@amd.com) --- Created attachment 290583 --> https://bugzilla.kernel.org/attachment.cgi?id=290583&action=edit 0001-drm-amd-display-Force-add-all-CRTCs-to-state-when-us.patch So the sequence looks like the following: 1. Non-blocking commit #1 requested, checked, swaps state and deferred to work queue. 2. Non-blocking commit #2 requested, checked, swaps state and deferred to work queue. Commits #1 and #2 don't touch any of the same core DRM objects (CRTCs, Planes, Connectors) so Commit #2 does not stall for Commit #1. DRM Private Objects have always been avoided in stall checks, so we have no safety from DRM core in this regard. 3. Due to system load commit #2 executes first and finishes its commit tail work. At the end of commit tail, as part of DRM core, it calls drm_atomic_state_put(). Since this was the pageflip IOCTL we likely already dropped the reference on the state held by the IOCTL itself. So it's going to actually free at this point. This eventually calls drm_atomic_state_clear() which does the following: obj->funcs->atomic_destroy_state(obj, state->private_objs[i].state); Note that it clears "state" here. Commit sets "state" to the following: state->private_objs[i].state = old_obj_state; obj->state = new_obj_state; Since Commit #1 swapped first this means Commit #2 actually does free Commit #1's private object. 4. Commit #1 then executes and we get a use after free. Same bug, it's just this was never corrupted before by the slab changes. It's been sitting dormant for 5.0~5.8. Attached is a patch that might help resolve this. -- You are receiving this mail because: You are watching the assignee of the bug. _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel