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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 EC5A8C433E6 for ; Wed, 17 Mar 2021 12:50:51 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3F76364F18 for ; Wed, 17 Mar 2021 12:50:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3F76364F18 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=uniontech.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=amd-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8D0406E57A; Wed, 17 Mar 2021 12:50:49 +0000 (UTC) Received: from regular1.263xmail.com (regular1.263xmail.com [211.150.70.195]) by gabe.freedesktop.org (Postfix) with ESMTPS id 75CD56E506 for ; Wed, 17 Mar 2021 09:19:16 +0000 (UTC) Received: from localhost (unknown [192.168.167.32]) by regular1.263xmail.com (Postfix) with ESMTP id 873CD1CD1; Wed, 17 Mar 2021 17:19:12 +0800 (CST) X-MAIL-GRAY: 0 X-MAIL-DELIVERY: 1 X-ADDR-CHECKED4: 1 X-ANTISPAM-LEVEL: 2 X-SKE-CHECKED: 1 X-ABS-CHECKED: 1 Received: from chenli.uniontech.com (unknown [58.246.122.242]) by smtp.263.net (postfix) whith ESMTP id P27338T140203174360832S1615972751696843_; Wed, 17 Mar 2021 17:19:12 +0800 (CST) X-IP-DOMAINF: 1 X-UNIQUE-TAG: <80d595a771cbbfef5a6834a3899fc2e0> X-RL-SENDER: chenli@uniontech.com X-SENDER: chenli@uniontech.com X-LOGIN-NAME: chenli@uniontech.com X-FST-TO: christian.koenig@amd.com X-SENDER-IP: 58.246.122.242 X-ATTACHMENT-NUM: 0 X-System-Flag: 0 Date: Wed, 17 Mar 2021 17:19:11 +0800 Message-ID: <87blbiyw6o.wl-chenli@uniontech.com> From: Chen Li To: Christian =?ISO-8859-1?Q?K=F6nig?= Subject: Re: [PATCH] radeon: use kvcalloc for relocs and chunks In-Reply-To: <03eefbb1-4d33-8a96-a53c-df1654a7d3f6@amd.com> References: <87czvyz4dd.wl-chenli@uniontech.com> <03eefbb1-4d33-8a96-a53c-df1654a7d3f6@amd.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?ISO-8859-4?Q?Goj=F2?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") X-Mailman-Approved-At: Wed, 17 Mar 2021 12:50:47 +0000 X-BeenThere: amd-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Alex Deucher , Chen Li , amd-gfx@lists.freedesktop.org Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Errors-To: amd-gfx-bounces@lists.freedesktop.org Sender: "amd-gfx" On Wed, 17 Mar 2021 15:55:47 +0800, Christian K=F6nig wrote: > = > Am 17.03.21 um 07:22 schrieb Chen Li: > > kvmalloc_array + __GFP_ZERO is the same with kvcalloc. > > = > > As for p->chunks, it will be used in: > > ``` > > if (ib_chunk->kdata) > > memcpy(parser->ib.ptr, ib_chunk->kdata, ib_chunk->length_dw * 4); > > ``` > > = > > If chunks doesn't zero out with __GFP_ZERO, it may point to somewhere e= lse, e.g., > > ``` > > Unable to handle kernel paging request at virtual address 0000000000010= 000 > > ... > > pc is at memcpy+0x84/0x250 > > ra is at radeon_cs_ioctl+0x368/0xb90 [radeon] > > ``` > > = > > after allocating chunks with __GFP_KERNEL/kvcalloc, this bug is fixed. > = > NAK to zeroing the chunks array. > = > That array should be fully initialized with data before using it, otherwi= se we > have a much more serious bug and zeroing it out only papers over the real= issue. > = > How did you trigger the NULL pointer deref above? Hi, Christian, thanks for reply! From radeon_cs_parser_init: ``` if (user_chunk.chunk_id =3D=3D RADEON_CHUNK_ID_IB) { if (!p->rdev || !(p->rdev->flags & RADEON_IS_AGP)) /****** chenli: chunks[0] come here and continue! ******/ continue; } p->chunks[i].kdata =3D kvmalloc_array(size, sizeof(uint32_t), GFP_KERNEL); ``` In my case, chunks[0] is not allocated because it is just get continued, so= it's not wired that kdata in "memcpy(parser->ib.ptr, ib_chunk->kdata, ib_chunk->leng= th_dw * 4);" trigger the invalid address. = = > = > Thanks, > Christian. > = > > Signed-off-by: Chen Li > > --- > > drivers/gpu/drm/radeon/radeon_cs.c | 6 +++--- > > 1 file changed, 3 insertions(+), 3 deletions(-) > > = > > diff --git a/drivers/gpu/drm/radeon/radeon_cs.c b/drivers/gpu/drm/radeo= n/radeon_cs.c > > index fb736ef9f9aa..059431689c2d 100644 > > --- a/drivers/gpu/drm/radeon/radeon_cs.c > > +++ b/drivers/gpu/drm/radeon/radeon_cs.c > > @@ -93,8 +93,8 @@ static int radeon_cs_parser_relocs(struct radeon_cs_p= arser *p) > > p->dma_reloc_idx =3D 0; > > /* FIXME: we assume that each relocs use 4 dwords */ > > p->nrelocs =3D chunk->length_dw / 4; > > - p->relocs =3D kvmalloc_array(p->nrelocs, sizeof(struct radeon_bo_list= ), > > - GFP_KERNEL | __GFP_ZERO); > > + p->relocs =3D kvcalloc(p->nrelocs, sizeof(struct radeon_bo_list), > > + GFP_KERNEL); > > if (p->relocs =3D=3D NULL) { > > return -ENOMEM; > > } > > @@ -299,7 +299,7 @@ int radeon_cs_parser_init(struct radeon_cs_parser *= p, void *data) > > } > > p->cs_flags =3D 0; > > p->nchunks =3D cs->num_chunks; > > - p->chunks =3D kvmalloc_array(p->nchunks, sizeof(struct radeon_cs_chun= k), GFP_KERNEL); > > + p->chunks =3D kvcalloc(p->nchunks, sizeof(struct radeon_cs_chunk), GF= P_KERNEL); > > if (p->chunks =3D=3D NULL) { > > return -ENOMEM; > > } > = > = > = Regards, Chen Li _______________________________________________ amd-gfx mailing list amd-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/amd-gfx