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=-0.5 required=3.0 tests=FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 0A689C33CB7 for ; Sat, 1 Feb 2020 17:11:55 +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 B9726206D3 for ; Sat, 1 Feb 2020 17:11:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B9726206D3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=sina.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 B72296E0F0; Sat, 1 Feb 2020 17:11:52 +0000 (UTC) Received: from mail3-166.sinamail.sina.com.cn (mail3-166.sinamail.sina.com.cn [202.108.3.166]) by gabe.freedesktop.org (Postfix) with SMTP id 2C9446E4DD for ; Sat, 1 Feb 2020 09:03:07 +0000 (UTC) Received: from unknown (HELO localhost.localdomain)([124.64.3.106]) by sina.com with ESMTP id 5E353EC1000026FF; Sat, 1 Feb 2020 17:02:59 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com X-SMAIL-MID: 46649154919310 From: Hillf Danton To: Dan Carpenter Subject: Re: KASAN: use-after-free Read in vgem_gem_dumb_create Date: Sat, 1 Feb 2020 17:02:47 +0800 Message-Id: <20200201090247.10928-1-hdanton@sina.com> In-Reply-To: <20200201043209.13412-1-hdanton@sina.com> References: <20200201043209.13412-1-hdanton@sina.com> MIME-Version: 1.0 X-Mailman-Approved-At: Sat, 01 Feb 2020 17:11:52 +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: robdclark@chromium.org, daniel@ffwll.ch, davem@davemloft.net, airlied@linux.ie, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, chris@chris-wilson.co.uk, linaro-mm-sig@lists.linaro.org, eric@anholt.net, seanpaul@chromium.org, dri-devel@lists.freedesktop.org, syzbot , alexander.deucher@amd.com, linux-media@vger.kernel.org, sumit.semwal@linaro.org, christian.koenig@amd.com, emil.velikov@collabora.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: amd-gfx-bounces@lists.freedesktop.org Sender: "amd-gfx" On Sat, 1 Feb 2020 09:17:57 +0300 Dan Carpenter wrote: > On Sat, Feb 01, 2020 at 12:32:09PM +0800, Hillf Danton wrote: > > > > Release obj in error path. > > > > --- a/drivers/gpu/drm/vgem/vgem_drv.c > > +++ b/drivers/gpu/drm/vgem/vgem_drv.c > > @@ -196,10 +196,10 @@ static struct drm_gem_object *vgem_gem_c > > return ERR_CAST(obj); > > > > ret = drm_gem_handle_create(file, &obj->base, handle); > > - drm_gem_object_put_unlocked(&obj->base); > > - if (ret) > > + if (ret) { > > + drm_gem_object_put_unlocked(&obj->base); > > return ERR_PTR(ret); > > - > > + } > > return &obj->base; > > Oh yeah. It's weird that we never noticed the success path was broken. > It's been that way for three years and no one noticed at all. Very > strange. > > Anyway, it already gets freed on error in drm_gem_handle_create() so > we should just delete the drm_gem_object_put_unlocked() here it looks > like. Good catch, Dan :P Would you please post a patch sometime convenient next week? Thanks Hillf _______________________________________________ amd-gfx mailing list amd-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/amd-gfx