From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 69C14171A9 for ; Mon, 22 May 2023 19:39:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DB198C433D2; Mon, 22 May 2023 19:39:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1684784373; bh=pkAJcn2bsmGeFnBFIbKnsi7Rkz/T8PhoD8Cbw3O+WJc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1kliUDPvK1kfsf7PaA8ilKYz48kVVFoXEtnJ3G6/lBWClKMM8LkaR6tBLj0LH3WYv k0x3SWQARqUOa4Z2MszhVHS3mmReNQIg5B8pnrJklBBykavsQ77CXrpXuaieP5qrUT DPicR3dfyGkHOlxt4Ez2MuSUgCpqdwOuPachwz10= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Nikita Zhandarovich , Rodrigo Vivi , Joonas Lahtinen , Sasha Levin Subject: [PATCH 6.3 033/364] drm/i915/dp: prevent potential div-by-zero Date: Mon, 22 May 2023 20:05:38 +0100 Message-Id: <20230522190413.660936878@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230522190412.801391872@linuxfoundation.org> References: <20230522190412.801391872@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Nikita Zhandarovich [ Upstream commit 0ff80028e2702c7c3d78b69705dc47c1ccba8c39 ] drm_dp_dsc_sink_max_slice_count() may return 0 if something goes wrong on the part of the DSC sink and its DPCD register. This null value may be later used as a divisor in intel_dsc_compute_params(), which will lead to an error. In the unlikely event that this issue occurs, fix it by testing the return value of drm_dp_dsc_sink_max_slice_count() against zero. Found by Linux Verification Center (linuxtesting.org) with static analysis tool SVACE. Fixes: a4a157777c80 ("drm/i915/dp: Compute DSC pipe config in atomic check") Signed-off-by: Nikita Zhandarovich Reviewed-by: Rodrigo Vivi Signed-off-by: Rodrigo Vivi Link: https://patchwork.freedesktop.org/patch/msgid/20230418140430.69902-1-n.zhandarovich@fintech.ru (cherry picked from commit 51f7008239de011370c5067bbba07f0207f06b72) Signed-off-by: Joonas Lahtinen Signed-off-by: Sasha Levin --- drivers/gpu/drm/i915/display/intel_dp.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 62cbab7402e93..c1825f8f885c2 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -1533,6 +1533,11 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp, pipe_config->dsc.slice_count = drm_dp_dsc_sink_max_slice_count(intel_dp->dsc_dpcd, true); + if (!pipe_config->dsc.slice_count) { + drm_dbg_kms(&dev_priv->drm, "Unsupported Slice Count %d\n", + pipe_config->dsc.slice_count); + return -EINVAL; + } } else { u16 dsc_max_output_bpp = 0; u8 dsc_dp_slice_count; -- 2.39.2