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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT 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 40940C04EB9 for ; Fri, 30 Nov 2018 00:18:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CC6AB20868 for ; Fri, 30 Nov 2018 00:18:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CC6AB20868 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726966AbeK3LZX (ORCPT ); Fri, 30 Nov 2018 06:25:23 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:41386 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726392AbeK3LZX (ORCPT ); Fri, 30 Nov 2018 06:25:23 -0500 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wAU099Ko124169 for ; Thu, 29 Nov 2018 19:18:01 -0500 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0a-001b2d01.pphosted.com with ESMTP id 2p2tdjga05-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 29 Nov 2018 19:18:01 -0500 Received: from localhost by e06smtp01.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Fri, 30 Nov 2018 00:17:55 -0000 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id wAU0Hsc650266238 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 30 Nov 2018 00:17:54 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9C9DF11C04A; Fri, 30 Nov 2018 00:17:54 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0064411C054; Fri, 30 Nov 2018 00:17:54 +0000 (GMT) Received: from ozlabs.au.ibm.com (unknown [9.192.253.14]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 30 Nov 2018 00:17:53 +0000 (GMT) Received: from tungsten.ozlabs.ibm.com (haven.au.ibm.com [9.192.254.114]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.au.ibm.com (Postfix) with ESMTPSA id 90D26A0198; Fri, 30 Nov 2018 11:17:52 +1100 (AEDT) Date: Fri, 30 Nov 2018 11:17:51 +1100 From: Sam Bobroff To: Daniel Vetter Cc: "airlied@gmail.com" , Dave Airlie , Dave Airlie , Linux Kernel Mailing List , dri-devel Subject: Re: [PATCH 2/2] drm/ast: Fix connector leak during driver unload References: <3350c5dd5ea08c71e4769ea3801290e7f9238a6c.1541397462.git.sbobroff@linux.ibm.com> <20181129020034.GA10328@tungsten.ozlabs.ibm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="YZ5djTAD1cGYuMQK" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.3 (2018-01-21) X-TM-AS-GCONF: 00 x-cbid: 18113000-4275-0000-0000-000002E8D616 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18113000-4276-0000-0000-000037F61BE8 Message-Id: <20181130001750.GA6776@tungsten.ozlabs.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-11-29_14:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1811290202 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --YZ5djTAD1cGYuMQK Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Nov 29, 2018 at 09:56:53AM +0100, Daniel Vetter wrote: > On Thu, Nov 29, 2018 at 9:05 AM Sam Bobroff wrot= e: > > > > On Thu, Nov 29, 2018 at 09:40:53AM +1000, Dave Airlie wrote: > > > On Mon, 5 Nov 2018 at 15:59, Sam Bobroff wro= te: > > > > > > > > When unloading the ast driver, a warning message is printed by > > > > drm_mode_config_cleanup() because a reference is still held to one = of > > > > the drm_connector structs. > > > > > > > > Correct this by calling drm_framebuffer_remove() in > > > > ast_fbdev_destroy(). > > > > > > > > Signed-off-by: Sam Bobroff > > > > --- > > > > drivers/gpu/drm/ast/ast_fb.c | 4 ++++ > > > > 1 file changed, 4 insertions(+) > > > > > > > > diff --git a/drivers/gpu/drm/ast/ast_fb.c b/drivers/gpu/drm/ast/ast= _fb.c > > > > index 0cd827e11fa2..655372ea81e9 100644 > > > > --- a/drivers/gpu/drm/ast/ast_fb.c > > > > +++ b/drivers/gpu/drm/ast/ast_fb.c > > > > @@ -263,6 +263,10 @@ static void ast_fbdev_destroy(struct drm_devic= e *dev, > > > > { > > > > struct ast_framebuffer *afb =3D &afbdev->afb; > > > > > > > > + /* drm_framebuffer_remove() expects us to hold a ref, which= it > > > > + * will drop, so take one: */ > > > > + drm_framebuffer_get(&afb->base); > > > > + drm_framebuffer_remove(&afb->base); > > > > > > This doesn't seem corret, no other driver does this pattern, and I > > > can't believe ast is special here. > > > > > > The get just doesn't make sense. > > > > Thanks for having a look at this, as I said in the cover letter I was > > concerned that it might not be a good fix. > > > > But the AST driver does seem to be special (or just old?) because it > > embeds the drm_framebuffer directly into ast_fbdev and (almost all) > > other drivers dynamically allocate and reference count theirs. > > > > The drm_framebuffer_get() certainly looks weird but it is there in order > > to cause drm_framebuffer_remove() to call legacy_remove_fb(), which it > > won't do unless the refcount is at least 2. (And because the > > drm_framebuffer isn't dynamically allocated in this case we don't really > > care about the reference count anyway.) > > > > An alternative might be to call legacy_remove_fb() directly, but it's > > declared static. Do you think it would be better to expose it and call > > it directly from the AST driver code? Or is there some other better way > > to put the drm_connectors? >=20 > Your problem isn't the dynamic fb vs. embedded fb for fbdev (you're > already using drm_framebuffer_unregister_private to handle that). Your > problem is you're not shutting down stuff on driver unload, which > means the fb is still in use. drm_atomic_helper_shutdown() takes care > of that for atomic drivers. >=20 > No idea anymore what to do for legacy code, probably need to open code > a shutdown sequence. Definitely not the above. > -Daniel Well, it looks like drm_crtc_force_disable_all() would also do the job, and from looking at nouveau_display_fini() it's used there as an alternative to drm_atomic_helper_shutdown(). Would it be reasonable to call that at the start of ast_fbdev_destroy() instead? (Testing shows that it does allow the drm_connector to be released. Is it enough/correct though?) Cheers, Sam. > --=20 > Daniel Vetter > Software Engineer, Intel Corporation > +41 (0) 79 365 57 48 - http://blog.ffwll.ch >=20 --YZ5djTAD1cGYuMQK Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCAAdFiEELWWF8pdtWK5YQRohMX8w6AQl/iIFAlwAgaIACgkQMX8w6AQl /iK4kwf/VNV58jJRgG00g3xQieQoDUoOUx0p72lWp4ucR+wbvou7paqyPMDwUPhG CY8Lg9D+X1cAKP4uCmotGBHeKMSTDy3pEgjbIC4BxcN2dDxKdyON29u8CnqDnF40 6S2TGyMIV2I4VdejyuFmPAPoSqJG5p28zLBzsAxoIh0Va8lSjrXOejz0x/OU3Tt4 FM0W/SDiNTIBARDvPBgWiCuWpCPECid4/oNlheyCF2+t6jTCaJLaZ03X7f35y8AL qjT9gh7GeVC3Sip1GXiFVWVT63WlDpf72LMuT5qMZrQtLOXSXZxuiKYGbAO8qijE aEiv7WfgOI4ufoiv4reFIAPKvaQ1iA== =su7o -----END PGP SIGNATURE----- --YZ5djTAD1cGYuMQK--