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 24D601A9B58 for ; Sat, 18 Apr 2026 12:12:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776514350; cv=none; b=TeBAjo3/UnsG+uoflk+3xFSjiuGYPRqaG0t+g1oDudmdXCatpJ3GtMooQw5gIWt9JBzGT0A9a2o6qsHyFf+KFrs1K2WTTfFWynF9IGUo7Gqhoh9lxLLx/ZCiNznBY+TtFjsSl/8rzzMwsNBLGdL4CoRwmFRuFPpfxalEyvM0SAM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776514350; c=relaxed/simple; bh=b9PenJjHaSudWajbzycGmt+Iph3cnRU02bJt70Fh7Eg=; h=Mime-Version:Content-Type:Date:Message-Id:Subject:Cc:To:From: References:In-Reply-To; b=jf3XlcRir+f6Kd31ZySX7I666rLMXAQtFixrvTSYFpYH6c61wImvjQX+Z76uqPqjoOpRxkeYINpMH7hrIDHpxeWcn6glBF7IuUYPOBhyA0wTa8UT9ozKJoX1MdX5zbZUNZMZZ/nCY+ZjjXNr7XLv9qXQmi7Y9F8GCITFWSydDmo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=m1yjrDgC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="m1yjrDgC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 86DDCC19424; Sat, 18 Apr 2026 12:12:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776514349; bh=b9PenJjHaSudWajbzycGmt+Iph3cnRU02bJt70Fh7Eg=; h=Date:Subject:Cc:To:From:References:In-Reply-To:From; b=m1yjrDgC2Vp3S9i2v6ibSL2JFghRG5C7W0hZT+LalgTRV1d7OnryWOSB6nnndhnYp dCbOL2num5eSmqu1bDi587r/2SOMZZa1nqWxhLf7M7JjN94lkCjoVu93rtzCfiuyzO NrF+DTMCzFGk+MYZGmNkqPxPJR+4SfVS4d7MdRsFaZuPBJoj53dseGveTtyZHtHA5e NKuYe8ftmP7kAh+2zEn9XPYZOL/ffb/0+53Ko/kcS2f4XDAplXWcFI2Ca0k5t57/xE CckFwhX1B9mrP2MOo7YpWRCfuj+3OuukgNtaYIFU785F7YAIjUnmC3XCOP4qKcb0pF Xg5ix46JWpC5A== Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Sat, 18 Apr 2026 14:12:25 +0200 Message-Id: Subject: Re: [PATCH] drm/nouveau/gsp: Fix possible NULL pointer dereference warning in r535_dmac_alloc Cc: , , , , , , , , , "sunliming" To: From: "Danilo Krummrich" References: <20260418071412.86022-1-sunliming@linux.dev> In-Reply-To: <20260418071412.86022-1-sunliming@linux.dev> On Sat Apr 18, 2026 at 9:14 AM CEST, sunliming wrote: > From: sunliming > > Fix below smatch warnings: > drivers/gpu/drm/nouveau/nvkm/subdev/gsp/rm/r535/disp.c:178 r535_dmac_allo= c() > warn: 'args' can also be NULL Please write a commit description that explains also the underlying problem= ; see more below. > Signed-off-by: sunliming > --- > drivers/gpu/drm/nouveau/nvkm/subdev/gsp/rm/r535/disp.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/rm/r535/disp.c b/dri= vers/gpu/drm/nouveau/nvkm/subdev/gsp/rm/r535/disp.c > index 6e63df816d85..6dec2623d0be 100644 > --- a/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/rm/r535/disp.c > +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/rm/r535/disp.c > @@ -172,6 +172,8 @@ r535_dmac_alloc(struct nvkm_disp *disp, u32 oclass, i= nt inst, u32 put_offset, > =20 > args =3D nvkm_gsp_rm_alloc_get(&disp->rm.object, (oclass << 16) | inst,= oclass, > sizeof(*args), dmac); > + if (!args) > + return -ENOMEM; Are we sure that this can ever return NULL in the first place? I know that nvkm_gsp_rm_alloc_get() internally checks for IS_ERR_OR_NULL(), but I could= n't find anything within the callchain that would actually return NULL. That said, I think IS_ERR_OR_NULL() checks are misleading. > if (IS_ERR(args)) > return PTR_ERR(args); > =20 > --=20 > 2.25.1