From nobody Sun Apr 12 18:37:51 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6203BC4332F for ; Tue, 20 Dec 2022 09:42:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233592AbiLTJlx (ORCPT ); Tue, 20 Dec 2022 04:41:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45616 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233569AbiLTJlZ (ORCPT ); Tue, 20 Dec 2022 04:41:25 -0500 Received: from m12.mail.163.com (m12.mail.163.com [220.181.12.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 731F817599 for ; Tue, 20 Dec 2022 01:41:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=5U/Q0 IzBncgGJ65mZDk0e6NuKaOGAn75Xs2OHH9bGHk=; b=SrkBw11w8K6FHxt1r/Cva GQWOb75ACnz7P5xM98IkqXOjfmO8KduGo4Pv8Xi7FjygF1zJFdFsOK1cgwI4gtKh IJ3JRQ+xud5UYjcCa/m1uk+LeX95NeT/jesrY9D1/ctk2Px2r0+2yJ7uTM6P29q3 vrWyHZx9Z+ZeDdw9r7kMUo= Received: from leanderwang-LC2.localdomain (unknown [111.206.145.21]) by zwqz-smtp-mta-g0-3 (Coremail) with SMTP id _____wB3j3r_gqFjgjtjAA--.34322S2; Tue, 20 Dec 2022 17:40:15 +0800 (CST) From: Zheng Wang To: zhi.a.wang@intel.com Cc: 1002992920@qq.com, airlied@gmail.com, airlied@linux.ie, alex000young@gmail.com, dri-devel@lists.freedesktop.org, gregkh@linuxfoundation.org, hackerzheng666@gmail.com, intel-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, joonas.lahtinen@linux.intel.com, linux-kernel@vger.kernel.org, security@kernel.org, tvrtko.ursulin@linux.intel.com, zhenyuw@linux.intel.com, zyytlz.wz@163.com Subject: [PATCH v5] drm/i915/gvt: fix double free bug in split_2MB_gtt_entry Date: Tue, 20 Dec 2022 17:40:14 +0800 Message-Id: <20221220094014.1128207-1-zyytlz.wz@163.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <11728bc1-7b59-1623-b517-d1a0d57eb275@intel.com> References: <11728bc1-7b59-1623-b517-d1a0d57eb275@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wB3j3r_gqFjgjtjAA--.34322S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7AFW8WFy7XF4DtF17trWxtFb_yoW5JF43pF W8XF4YyF48ZF1Ivw47uF18AFy3Z3W3Xa48WrZ7Ka4Ykrs0qF1qkr90yFW5Xr97uFWDAw4f Cr4DJrW3Ca4jvaDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0zRomh7UUUUU= X-Originating-IP: [111.206.145.21] X-CM-SenderInfo: h2113zf2oz6qqrwthudrp/xtbBzgbdU2I0W3z3ogAAsi Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" If intel_gvt_dma_map_guest_page failed, it will call ppgtt_invalidate_spt, which will finally free the spt. But the caller function ppgtt_populate_spt_by_guest_entry does not notice that, it will free spt again in its error path. Fix this by undoing the mapping of DMA address and freeing sub_spt. Besides, leave the handle of spt destroy to caller function instead of callee function when error occurs. Fixes: b901b252b6cf ("drm/i915/gvt: Add 2M huge gtt support") Signed-off-by: Zheng Wang Reviewed-by: Zhenyu Wang --- v5: - remove unnecessary switch-case code for there is only one particular case, correct the unmap target from parent_spt to sub_spt.add more details in commit message. All suggested by Zhenyu v4: - fix by undo the mapping of DMA address and free sub_spt suggested by Zhi v3: - correct spelling mistake and remove unused variable suggested by Greg v2: https://lore.kernel.org/all/20221006165845.1735393-1-zyytlz.wz@163.com/ v1: https://lore.kernel.org/all/20220928033340.1063949-1-zyytlz.wz@163.com/ --- drivers/gpu/drm/i915/gvt/gtt.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c index 51e5e8fb505b..4d478a59eb7d 100644 --- a/drivers/gpu/drm/i915/gvt/gtt.c +++ b/drivers/gpu/drm/i915/gvt/gtt.c @@ -1209,10 +1209,8 @@ static int split_2MB_gtt_entry(struct intel_vgpu *vg= pu, for_each_shadow_entry(sub_spt, &sub_se, sub_index) { ret =3D intel_gvt_dma_map_guest_page(vgpu, start_gfn + sub_index, PAGE_SIZE, &dma_addr); - if (ret) { - ppgtt_invalidate_spt(spt); - return ret; - } + if (ret) + goto err; sub_se.val64 =3D se->val64; =20 /* Copy the PAT field from PDE. */ @@ -1231,6 +1229,18 @@ static int split_2MB_gtt_entry(struct intel_vgpu *vg= pu, ops->set_pfn(se, sub_spt->shadow_page.mfn); ppgtt_set_shadow_entry(spt, se, index); return 0; +err: + /* Undone the existing mappings of DMA addr. */ + for_each_present_shadow_entry(sub_spt, &sub_se, sub_index) { + gvt_vdbg_mm("invalidate 4K entry\n"); + ppgtt_invalidate_pte(sub_spt, &sub_se); + } + /* Release the new allocated spt. */ + trace_spt_change(sub_spt->vgpu->id, "release", sub_spt, + sub_spt->guest_page.gfn, sub_spt->shadow_page.type); + ppgtt_free_spt(sub_spt); + sub_spt =3D NULL; + return ret; } =20 static int split_64KB_gtt_entry(struct intel_vgpu *vgpu, --=20 2.25.1