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 X-Spam-Level: X-Spam-Status: No, score=-2.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED, USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D9522C43381 for ; Mon, 11 Mar 2019 10:12:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8F07220657 for ; Mon, 11 Mar 2019 10:12:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="g6g94Rtt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727154AbfCKKME (ORCPT ); Mon, 11 Mar 2019 06:12:04 -0400 Received: from mail-qk1-f196.google.com ([209.85.222.196]:45852 "EHLO mail-qk1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726943AbfCKKMD (ORCPT ); Mon, 11 Mar 2019 06:12:03 -0400 Received: by mail-qk1-f196.google.com with SMTP id z76so1458998qkb.12 for ; Mon, 11 Mar 2019 03:12:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=lqzkT6jK38j+AXApCJ+CsCAlikIN6AkZJjM6gE9TWJM=; b=g6g94Rtt3/iQsz61Xwsu2kUWRqcY2JeYA9qe3L4kb+7SS+z7TQtB5xZTGlub6xKwly cJ2Ftyx1KjJ62gLCSS7t9bnySHGqdbF4T6ymFiCMd3UGUvVc7z8Kl9RMBley01tKld5k inHbL1tPVPTwxA8tyKLzmDaB6FTb5PIBZnCPkW4WwBKiedQYAtwl1/u3DWKJwisUPEfJ 6kPeCZIeWuZBAYi/qzgz5Jnf04PlXponPBpvqS/QLl5TbpOU6DnOlnicF9BCaaMGmbrh Ym/GqVKk9G65NioL90dCKFiQT503J+28k1EnZYAdtKh82JL8TZekq7yWUucen4vQNkye YLhA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=lqzkT6jK38j+AXApCJ+CsCAlikIN6AkZJjM6gE9TWJM=; b=UdMXTw9sVpB8M0WU9Ux2cOBaG3jqoOzQpmB3rTNp7TN/1cIpove/JHvkepDeObNtmk anagXndTGkajxCI9V8qOFebIAgxaJ3BQEvhysO4KxcOpw9arGywVmgppFpNnuQOI2Tr0 jGRAx+709JQ5LqcCefE3in7Gt4x4eABniVmVlJhqUu5ra4Gn19Yoz9zXSkwRw8XH43S7 5kI6NwxPxE+uqHjEK8ld2JlcXQzKyPjsdQj3n0VMylFc0iBl998MKld3QuvYwe+Dm58t P1V/ujR6sDc6z+pT5Rl2M47i8BC7s2387cnGEgYs4nK7kEFaKpPHwjmgp4qh7mIsJ6cW uwKw== X-Gm-Message-State: APjAAAU0puiVw03HdzqS4eG4hzY0nENEMJjve4D63d/6I5cW4zx3Wmqh +hd+3qKMOHN35vSieP4KNi4= X-Google-Smtp-Source: APXvYqzjasmQznTAEoffDs3qE/dWUO4gHW5DijyodpQZVv50nbITI/gYp48TFMT2qHWl1MfPX6IIOg== X-Received: by 2002:a37:553:: with SMTP id 80mr22313879qkf.19.1552299122948; Mon, 11 Mar 2019 03:12:02 -0700 (PDT) Received: from smtp.gmail.com ([143.107.45.1]) by smtp.gmail.com with ESMTPSA id g82sm2859561qkb.34.2019.03.11.03.12.00 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Mon, 11 Mar 2019 03:12:02 -0700 (PDT) Date: Mon, 11 Mar 2019 07:11:59 -0300 From: Rodrigo Siqueira To: Gerd Hoffmann Cc: David Airlie , Daniel Vetter , virtualization@lists.linux-foundation.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] drm/bochs: Fix NULL dereference on atomic_disable helper Message-ID: <20190311101159.t6mbzm5sdwuh5muc@smtp.gmail.com> References: <20190310212150.xhhb4abzm7j3ain2@smtp.gmail.com> <20190311062200.4mtel3j5fjxtxrcf@sirius.home.kraxel.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="drhezydywvhjq3od" Content-Disposition: inline In-Reply-To: <20190311062200.4mtel3j5fjxtxrcf@sirius.home.kraxel.org> User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --drhezydywvhjq3od Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 03/11, Gerd Hoffmann wrote: > On Sun, Mar 10, 2019 at 06:21:50PM -0300, Rodrigo Siqueira wrote: > > When the subtest basic-plain-flip from IGT project was executed on Bochs > > driver, the following bug appears: > >=20 > > BUG: unable to handle kernel NULL pointer dereference at 00000000000000= 00 >=20 > > ? drm_atomic_helper_commit_modeset_disables+0x396/0x3e0 [drm_kms_helpe= r] >=20 > > +static void bochs_crtc_atomic_disable(struct drm_crtc *crtc, > > + struct drm_crtc_state *old_state) > > +{ > > +} > > + > > static void bochs_crtc_atomic_flush(struct drm_crtc *crtc, > > struct drm_crtc_state *old_crtc_state) > > { > > @@ -66,6 +71,7 @@ static const struct drm_crtc_funcs bochs_crtc_funcs = =3D { > > static const struct drm_crtc_helper_funcs bochs_helper_funcs =3D { > > .mode_set_nofb =3D bochs_crtc_mode_set_nofb, > > .atomic_enable =3D bochs_crtc_atomic_enable, > > + .atomic_disable =3D bochs_crtc_atomic_disable, >=20 > Shouldn't we make the callback optional instead of adding empty dummy > functions to drivers? Hi Gerd, I agree, and I can work in this issue. Just one question, should we make atomic_enable optional as well? =20 Thanks for your feedback, Best Regards > cheers, > Gerd >=20 --=20 Rodrigo Siqueira https://siqueira.tech Graduate Student Department of Computer Science University of S=E3o Paulo --drhezydywvhjq3od Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEE4tZ+ii1mjMCMQbfkWJzP/comvP8FAlyGNG8ACgkQWJzP/com vP8wsw//UrL8vOCTOcYISOmd6tDS5RI41osGF/+I4UGtvgY9czxtp/cpff7wdgXb fOKvat7nsgRrX1HtfKbf/nVflpI9ifyrtzCGrip8jor7Tyd5luhXSVfeqjvbYYbm V1hoz8zU0nXKgM+ysgtRrBvLTDWpzgWw8ruvEJmHKoVX2W2PSptRsYGyhbbkXn7w YhKjEstNbL9Bhswd7HTN91udpqUFgOMCld4Zz2XPoO3bvWEM5TGYQMWFcprsDyLQ LpuSfftjkoJnXuzz+fOOI4+tBKJaBUOa/OJcSzwWV79jKGMucKI8jrSdY6x/sZGv LG8+/z5knRAUrrCAByjalucp2CFohe4Xgl0FEtcvNVnK7ShiTFwtuN/M2HqdnjaC Gw2NCiAuA7ZvXRDLgiCpjnejcG5kF9oPTGVkOtV0FoEn4j/u7OohvWGtq7RvPU+Y +BJkwe0itpXiFk8BpoPfWfg5cFi8oEY2PiLYDqjYSxjGv0WxTAnwgFqiwNVqwwlN cQgJUxvUUU015kyyHHZj8bY6xms11Wp0NF2MR8V1EuMF8w2XBfEM4DsTpvoTojRz d47QaG7jQBR5sfMu0vMjAbUMctxK4tpbxQj1I3Tg8B+QrNU3IVT8ufDbw4POMltK g2f/m6xDHBk9o0mIR528WBjf48zAfOQSHmEJtptQ2U7YB4E5GX4= =4Sg3 -----END PGP SIGNATURE----- --drhezydywvhjq3od--