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=-16.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 47929C47082 for ; Tue, 8 Jun 2021 08:57:23 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 0EFA86101A for ; Tue, 8 Jun 2021 08:57:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0EFA86101A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:List-Subscribe:List-Help: List-Post:List-Archive:List-Unsubscribe:List-Id:Message-Id:Date:Subject:Cc:To :From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=cb5k5X8gHx1eJECj9B+EHGIB4CdfbDETVIgnVD77URU=; b=dglFhOdCDdDj4N RJQXTQIOpZ9UpsWf/4Gmi3V2Ob+qAPzYKMlcQ8A2JEzi9DBJdprhItxm4Izyy+jBmj/XICZnFLyoT U4r3j5SmM0zb2EbkEtomLTFG8Jvo/7VTdsckL8VlfIzNnhZ8cp9mTA2vUMm8Qccgwn/vd8gANnHSU U0AKWjQGmE3/+2s/eI08uwM+uee/QaTwcrd2Wsg/uO6iLkULYnesVpMqox9s+ULLImzrhK0TDtQsu N3ZDA/4o/RqCryE0FufBG29YcV/0b2UcBb0fpchK/jbNAHDT3oX1KquIjX46HuO1epKuOD2fTFijt +nW6Z6HTts4NTfO0a9zg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lqXWJ-007DHJ-8I; Tue, 08 Jun 2021 08:55:35 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lqXWF-007DEu-7g for linux-arm-kernel@lists.infradead.org; Tue, 08 Jun 2021 08:55:33 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 81184113E; Tue, 8 Jun 2021 01:55:24 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id CB4863F719; Tue, 8 Jun 2021 01:55:22 -0700 (PDT) From: Mark Rutland To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Mark Rutland , Arnd Bergmann , Catalin Marinas , Daniel Vetter , David Airlie , Emma Anholt , Maxime Ripard , Will Deacon , dri-devel@lists.freedesktop.org Subject: [PATCH] drm/vc4: fix vc4_atomic_commit_tail() logic Date: Tue, 8 Jun 2021 09:55:12 +0100 Message-Id: <20210608085513.2069-1-mark.rutland@arm.com> X-Mailer: git-send-email 2.11.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210608_015531_377815_EC150CF8 X-CRM114-Status: GOOD ( 17.31 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org In vc4_atomic_commit_tail() we iterate of the set of old CRTCs, and attempt to wait on any channels which are still in use. When we iterate over the CRTCs, we have: * `i` - the index of the CRTC * `channel` - the channel a CRTC is using When we check the channel state, we consult: old_hvs_state->fifo_state[channel].in_use ... but when we wait for the channel, we erroneously wait on: old_hvs_state->fifo_state[i].pending_commit ... rather than: old_hvs_state->fifo_state[channel].pending_commit ... and this bogus access has been observed to result in boot-time hangs on some arm64 configurations, and can be detected using KASAN. FIx this by using the correct index. I've tested this on a Raspberry Pi 3 model B v1.2 with KASAN. Trimmed KASAN splat: | ================================================================== | BUG: KASAN: slab-out-of-bounds in vc4_atomic_commit_tail+0x1cc/0x910 | Read of size 8 at addr ffff000007360440 by task kworker/u8:0/7 | CPU: 2 PID: 7 Comm: kworker/u8:0 Not tainted 5.13.0-rc3-00009-g694c523e7267 #3 | | Hardware name: Raspberry Pi 3 Model B (DT) | Workqueue: events_unbound deferred_probe_work_func | Call trace: | dump_backtrace+0x0/0x2b4 | show_stack+0x1c/0x30 | dump_stack+0xfc/0x168 | print_address_description.constprop.0+0x2c/0x2c0 | kasan_report+0x1dc/0x240 | __asan_load8+0x98/0xd4 | vc4_atomic_commit_tail+0x1cc/0x910 | commit_tail+0x100/0x210 | ... | | Allocated by task 7: | kasan_save_stack+0x2c/0x60 | __kasan_kmalloc+0x90/0xb4 | vc4_hvs_channels_duplicate_state+0x60/0x1a0 | drm_atomic_get_private_obj_state+0x144/0x230 | vc4_atomic_check+0x40/0x73c | drm_atomic_check_only+0x998/0xe60 | drm_atomic_commit+0x34/0x94 | drm_client_modeset_commit_atomic+0x2f4/0x3a0 | drm_client_modeset_commit_locked+0x8c/0x230 | drm_client_modeset_commit+0x38/0x60 | drm_fb_helper_set_par+0x104/0x17c | fbcon_init+0x43c/0x970 | visual_init+0x14c/0x1e4 | ... | | The buggy address belongs to the object at ffff000007360400 | which belongs to the cache kmalloc-128 of size 128 | The buggy address is located 64 bytes inside of | 128-byte region [ffff000007360400, ffff000007360480) | The buggy address belongs to the page: | page:(____ptrval____) refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7360 | flags: 0x3fffc0000000200(slab|node=0|zone=0|lastcpupid=0xffff) | raw: 03fffc0000000200 dead000000000100 dead000000000122 ffff000004c02300 | raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 | page dumped because: kasan: bad access detected | | Memory state around the buggy address: | ffff000007360300: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb | ffff000007360380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc | >ffff000007360400: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc | ^ | ffff000007360480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc | ffff000007360500: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb | ================================================================== Link: https://lore.kernel.org/r/4d0c8318-bad8-2be7-e292-fc8f70c198de@samsung.com Link: https://lore.kernel.org/linux-arm-kernel/20210607151740.moncryl5zv3ahq4s@gilmour Signed-off-by: Mark Rutland Reported-by: Marek Szyprowski Cc: Arnd Bergmann Cc: Catalin Marinas Cc: Daniel Vetter Cc: David Airlie Cc: Emma Anholt Cc: Maxime Ripard Cc: Will Deacon Cc: dri-devel@lists.freedesktop.org --- drivers/gpu/drm/vc4/vc4_kms.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c index bb5529a7a9c2..948b3a58aad1 100644 --- a/drivers/gpu/drm/vc4/vc4_kms.c +++ b/drivers/gpu/drm/vc4/vc4_kms.c @@ -372,7 +372,7 @@ static void vc4_atomic_commit_tail(struct drm_atomic_state *state) if (!old_hvs_state->fifo_state[channel].in_use) continue; - ret = drm_crtc_commit_wait(old_hvs_state->fifo_state[i].pending_commit); + ret = drm_crtc_commit_wait(old_hvs_state->fifo_state[channel].pending_commit); if (ret) drm_err(dev, "Timed out waiting for commit\n"); } -- 2.11.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel