From patchwork Tue Sep 1 21:59:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephen Boyd X-Patchwork-Id: 11749949 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 06BB4618 for ; Wed, 2 Sep 2020 07:08:17 +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 D965D2137B for ; Wed, 2 Sep 2020 07:08:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="mcHPPLl1" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D965D2137B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.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 1B5046E904; Wed, 2 Sep 2020 07:08:00 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mail-pl1-x643.google.com (mail-pl1-x643.google.com [IPv6:2607:f8b0:4864:20::643]) by gabe.freedesktop.org (Postfix) with ESMTPS id 3CD516E0BC for ; Tue, 1 Sep 2020 21:59:45 +0000 (UTC) Received: by mail-pl1-x643.google.com with SMTP id t11so1244914plr.5 for ; Tue, 01 Sep 2020 14:59:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=mEANC8bA1AYbgYd33w7o7zlvFLzbGxcnZ/R/0LR11Po=; b=mcHPPLl1tJgo1pjkRyl5UZfnK2CPwjRFWOAUfeR9WjY1yrGmK0kVnT9k6vfs0pdww/ pNZgTRL7n9fneMrcNwjJKBE0UagE9fHe1AM5x5GNnLbB57EGtq2c+GTKOgD9XsVVq1A4 tvgaUUw3YvhVlVY5UbTWPI2nngZb0OAeGZbfk= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=mEANC8bA1AYbgYd33w7o7zlvFLzbGxcnZ/R/0LR11Po=; b=kcQdOub2+nqcunrD9N5daTEHLExlZVf6+bANOmaXTW2lTKeVE9BjkmUceiiVpSOQCE tg/f2+tVkK4bmnx7ptp7IyGnlqMN76gHuyFk8ldhD0bPcM8WJ4yUwcZ1uRD1iQZjAce6 VwBenXp77sOaqn2Jon3XQ6kWeaHdkd1Tz1HQ6sd2NZaDm8cZT3RywyVqSfPmgb+RyHpV n6Oka3vzR31Rv8UBOH3INCwg0XdcfLUFP5J448JYujKcJ1mB6d0JaN0VoeN+ExY7tyvy LUxopdf6jbuKBjV0HjVRAkI6XmG35UJrqHgqL6duTNJrghLLXxZsfuOxPvF0293LzQxF t6iA== X-Gm-Message-State: AOAM5300U5uaY9msBFrEZx9A5TIGGinOAKj1qexDjsaL18BzGdMmnhFT 0Z39Kfwow24UlINlhttGB9kgog== X-Google-Smtp-Source: ABdhPJz63bfH2BlH4Q6m23NnWgfqc24pUWHiyD6JlgU45wIroDyRBKQhRqJnp0qoa5/DZyjv1ZVlTA== X-Received: by 2002:a17:902:b714:: with SMTP id d20mr3178600pls.103.1598997584863; Tue, 01 Sep 2020 14:59:44 -0700 (PDT) Received: from smtp.gmail.com ([2620:15c:202:1:3e52:82ff:fe6c:83ab]) by smtp.gmail.com with ESMTPSA id q5sm3044037pfu.16.2020.09.01.14.59.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Sep 2020 14:59:44 -0700 (PDT) From: Stephen Boyd To: Rob Clark Subject: [PATCH 1/2] drm/msm: Avoid div-by-zero in dpu_crtc_atomic_check() Date: Tue, 1 Sep 2020 14:59:41 -0700 Message-Id: <20200901215942.2559119-2-swboyd@chromium.org> X-Mailer: git-send-email 2.28.0.402.g5ffc5be6b7-goog In-Reply-To: <20200901215942.2559119-1-swboyd@chromium.org> References: <20200901215942.2559119-1-swboyd@chromium.org> MIME-Version: 1.0 X-Mailman-Approved-At: Wed, 02 Sep 2020 07:07:59 +0000 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: freedreno@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Sean Paul , Abhinav Kumar , Sean Paul Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" The cstate->num_mixers member is only set to a non-zero value once dpu_encoder_virt_mode_set() is called, but the atomic check function can be called by userspace before that. Let's avoid the div-by-zero here and inside _dpu_crtc_setup_lm_bounds() by skipping this part of the atomic check if dpu_encoder_virt_mode_set() hasn't been called yet. This fixes an UBSAN warning: UBSAN: Undefined behaviour in drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c:860:31 division by zero CPU: 7 PID: 409 Comm: frecon Tainted: G S 5.4.31 #128 Hardware name: Google Trogdor (rev0) (DT) Call trace: dump_backtrace+0x0/0x14c show_stack+0x20/0x2c dump_stack+0xa0/0xd8 __ubsan_handle_divrem_overflow+0xec/0x110 dpu_crtc_atomic_check+0x97c/0x9d4 drm_atomic_helper_check_planes+0x160/0x1c8 drm_atomic_helper_check+0x54/0xbc drm_atomic_check_only+0x6a8/0x880 drm_atomic_commit+0x20/0x5c drm_atomic_helper_set_config+0x98/0xa0 drm_mode_setcrtc+0x308/0x5dc drm_ioctl_kernel+0x9c/0x114 drm_ioctl+0x2ac/0x4b0 drm_compat_ioctl+0xe8/0x13c __arm64_compat_sys_ioctl+0x184/0x324 el0_svc_common+0xa4/0x154 el0_svc_compat_handler+0x Cc: Abhinav Kumar Cc: Jeykumar Sankaran Cc: Jordan Crouse Cc: Sean Paul Fixes: 25fdd5933e4c ("drm/msm: Add SDM845 DPU support") Signed-off-by: Stephen Boyd --- drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c index f272a8d0f95b..74294b5ed93f 100644 --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c @@ -881,7 +881,7 @@ static int dpu_crtc_atomic_check(struct drm_crtc *crtc, struct drm_plane *plane; struct drm_display_mode *mode; - int cnt = 0, rc = 0, mixer_width, i, z_pos; + int cnt = 0, rc = 0, mixer_width = 0, i, z_pos; struct dpu_multirect_plane_states multirect_plane[DPU_STAGE_MAX * 2]; int multirect_count = 0; @@ -914,9 +914,11 @@ static int dpu_crtc_atomic_check(struct drm_crtc *crtc, memset(pipe_staged, 0, sizeof(pipe_staged)); - mixer_width = mode->hdisplay / cstate->num_mixers; + if (cstate->num_mixers) { + mixer_width = mode->hdisplay / cstate->num_mixers; - _dpu_crtc_setup_lm_bounds(crtc, state); + _dpu_crtc_setup_lm_bounds(crtc, state); + } crtc_rect.x2 = mode->hdisplay; crtc_rect.y2 = mode->vdisplay;