From nobody Sun May 10 20:32:18 2026 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 D3B98C433F5 for ; Sun, 24 Apr 2022 18:35:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237132AbiDXSiY (ORCPT ); Sun, 24 Apr 2022 14:38:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48156 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229929AbiDXSiU (ORCPT ); Sun, 24 Apr 2022 14:38:20 -0400 Received: from mail-wr1-x42e.google.com (mail-wr1-x42e.google.com [IPv6:2a00:1450:4864:20::42e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0E8FFDFA5; Sun, 24 Apr 2022 11:35:15 -0700 (PDT) Received: by mail-wr1-x42e.google.com with SMTP id d5so2748723wrb.6; Sun, 24 Apr 2022 11:35:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=349XFvM6t5JIYAzx/9jOMxcyDaGjEC8LJK6aTpUuIMg=; b=RximP2STPGTwfaqjRxZ9EaaaNjMB9VPGv+TMWWc1/rmkTluj14SIJeUnLigW7BRhQr rQ14jBCh4dcxCWQ6LqpUPREv+cZcMEaAXPK/hUnSQsZc80brfS7dEmf3YifOui/TYODB g3Hp0CvlGf8WOeRe74ibnhSu3ltQ/0c3Wg0/hbHCpRX/4rDdnef3b585uAUWHRatJGN1 aGnQaOJb6XxO+nhaKYETvz3XXDtWmzu/vLfeXFI2IzhiPKLEYmiF88e+UQAKqpfNQzjT iFWKUcRFQDyjOLxJUo8HOz1XDUQxohHfqWj9KxVDr1CXx+JkFKtIXIZehGa9r/w3DtBk N4NQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=349XFvM6t5JIYAzx/9jOMxcyDaGjEC8LJK6aTpUuIMg=; b=WZqpldrelKiqdcKkaIx3AhDjbBGxCkQ9bD6ZIt2PibrnYaAZ3GPBoI7N4l9EnT1zI/ l9JWC8lUHsFIyHOi4x1Coq4Ya9fbeq9fJrFZOJPqLsIHTkb+tLDex1yifW6E/jUbyBuU g5eLEVBUphFaKx8LCiBZ9BqkDnyyZPgtKyJQjgO66SmPwOKt8JlTJLFIaaHfJr2ey38Y KeYWo1ekPGMd1Gc0M7HxHLG0GBQDcJRfLZXx4d1G0685dJFtSq0HPnO7xrYzL+wZTWRW 2Yc80Vpy7VzmqyOe3uXwdxVbxSiwq2OJA2tLUUO65SFYt/cZY+ej07vPJeUTKbT5by2q po7Q== X-Gm-Message-State: AOAM5334u/awFpKQTsxbj+c3pYY1eaFHsPD6LmBrzzrYoD5KbgamtZkb 9mghT1wL9Pfim0nHsqJGhXItrgR6mNh2Ig== X-Google-Smtp-Source: ABdhPJxhKw8Ct/ffWL61Xq54wzGLON3haioc9TF0zqvEjFjtlU0qST5fxv3vVDHYSfiWPgNc6TwUCA== X-Received: by 2002:a05:6000:1789:b0:20a:9f94:1620 with SMTP id e9-20020a056000178900b0020a9f941620mr11858147wrg.640.1650825314073; Sun, 24 Apr 2022 11:35:14 -0700 (PDT) Received: from localhost (cpc154979-craw9-2-0-cust193.16-3.cable.virginm.net. [80.193.200.194]) by smtp.gmail.com with ESMTPSA id d2-20020a056000186200b0020a7be3f1d2sm8442792wri.53.2022.04.24.11.35.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 24 Apr 2022 11:35:13 -0700 (PDT) From: Colin Ian King To: Emma Anholt , David Airlie , Daniel Vetter , Melissa Wen , "Juan A . Suarez Romero" , dri-devel@lists.freedesktop.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] drm/v3d: Fix null pointer dereference of pointer perfmon Date: Sun, 24 Apr 2022 19:35:12 +0100 Message-Id: <20220424183512.1365683-1-colin.i.king@gmail.com> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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_pe= rfmon.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 =3D perfmon->ncounters; + u8 ncounters; =20 if (WARN_ON_ONCE(!perfmon || v3d->active_perfmon)) return; =20 + ncounters =3D perfmon->ncounters; mask =3D GENMASK(ncounters - 1, 0); =20 for (i =3D 0; i < ncounters; i++) { --=20 2.35.1