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 7996CC433EF for ; Tue, 7 Jun 2022 19:02:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353001AbiFGTB6 (ORCPT ); Tue, 7 Jun 2022 15:01:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58806 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352146AbiFGSQ4 (ORCPT ); Tue, 7 Jun 2022 14:16:56 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 80A44BF62; Tue, 7 Jun 2022 10:50:42 -0700 (PDT) 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 1CCF861650; Tue, 7 Jun 2022 17:50:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F000C34115; Tue, 7 Jun 2022 17:50:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1654624241; bh=dbWiRrbUEdq/jShUoMSStxSROdj/mfEgDgb1SJh4nPY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zM/3A9iE9QpSvLllz/GMnTnGgE35Iy2MkzjaHED4DkAe4u2cWtsfq6I9mGP0EWtxz nbBk65UIpvUvwCQFEKuNUOjnvtxesF52qquQVDQ+4xZRUEXkgRpMVYR8xW3792Jz9T 5TY6dcA6IfwObqBD5bwNeCNO7AxhXhQMc5JLw/vw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Colin Ian King , "Juan A. Suarez" , Melissa Wen , Sasha Levin Subject: [PATCH 5.15 255/667] drm/v3d: Fix null pointer dereference of pointer perfmon Date: Tue, 7 Jun 2022 18:58:40 +0200 Message-Id: <20220607164942.431058986@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220607164934.766888869@linuxfoundation.org> References: <20220607164934.766888869@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Colin Ian King [ Upstream commit ce7a1ecf3f9f1fccaf67295307614511d8e11b13 ] In the unlikely event that pointer perfmon is null the WARN_ON return path occurs after the pointer has already been deferenced. Fix this by only dereferencing perfmon after it has been null checked. Fixes: 26a4dc29b74a ("drm/v3d: Expose performance counters to userspace") Signed-off-by: Colin Ian King Reviewed-by: Juan A. Suarez Signed-off-by: Melissa Wen Link: https://patchwork.freedesktop.org/patch/msgid/20220424183512.1365683-1-colin.i.king@gmail.com Signed-off-by: Sasha Levin --- drivers/gpu/drm/v3d/v3d_perfmon.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/v3d/v3d_perfmon.c b/drivers/gpu/drm/v3d/v3d_perfmon.c index 0288ef063513..f6a88abccc7d 100644 --- a/drivers/gpu/drm/v3d/v3d_perfmon.c +++ b/drivers/gpu/drm/v3d/v3d_perfmon.c @@ -25,11 +25,12 @@ void v3d_perfmon_start(struct v3d_dev *v3d, struct v3d_perfmon *perfmon) { unsigned int i; u32 mask; - u8 ncounters = perfmon->ncounters; + u8 ncounters; if (WARN_ON_ONCE(!perfmon || v3d->active_perfmon)) return; + ncounters = perfmon->ncounters; mask = GENMASK(ncounters - 1, 0); for (i = 0; i < ncounters; i++) { -- 2.35.1