From nobody Wed Nov 19 14:03:21 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org ARC-Seal: i=1; a=rsa-sha256; t=1615937639; cv=none; d=zohomail.com; s=zohoarc; b=luTvdjut6bRHZWUADpd3aIjNt3g0TfVXDQcyU8raWoFADDNbfvWeXURfmsM2cb8Y3V8TQsQCmPCm8BtY/hPtWa55iClvQOaSPZ5uC0wTPTgQqVQroEkgfZiwx9QQ0e++U3wdfgltC7/4EWSTg6kO7VBDh2P/70Z3emACVi1lTm0= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1615937639; h=Content-Transfer-Encoding:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=Z63XpTFYvxamHt5jS4VSP2Pgz2274CpreI23Pi+tpTM=; b=R3DMJYWhGpIipWVO/Zot94wb83augVaXxzj4wBV3qk2DF11Vwg7x7T1iJ9gz4HYApb/yhfWm2u4N9n9dcmeEXc2UId09+Hj1g1dSF4zKWA2luDZuT2MySbAzsxe5q4hcIQlHpUP/YQzln30Clt0ZpGeNbgkcvODh4KgijhKUWNU= ARC-Authentication-Results: i=1; mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1615937639672608.0798157621462; Tue, 16 Mar 2021 16:33:59 -0700 (PDT) Received: from localhost ([::1]:53338 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lMJCI-0004jU-Gj for importer@patchew.org; Tue, 16 Mar 2021 19:33:58 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59832) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lMJ9l-0002fR-2P for qemu-devel@nongnu.org; Tue, 16 Mar 2021 19:31:21 -0400 Received: from mail.ilande.co.uk ([2001:41c9:1:41f::167]:33384 helo=mail.default.ilande.uk0.bigv.io) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lMJ9j-0007LO-5v for qemu-devel@nongnu.org; Tue, 16 Mar 2021 19:31:20 -0400 Received: from host109-156-104-46.range109-156.btcentralplus.com ([109.156.104.46] helo=kentang.home) by mail.default.ilande.uk0.bigv.io with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lMJ9g-0006Mg-PX; Tue, 16 Mar 2021 23:31:22 +0000 From: Mark Cave-Ayland To: qemu-devel@nongnu.org, alxndr@bu.edu Date: Tue, 16 Mar 2021 23:30:24 +0000 Message-Id: <20210316233024.13560-5-mark.cave-ayland@ilande.co.uk> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210316233024.13560-1-mark.cave-ayland@ilande.co.uk> References: <20210316233024.13560-1-mark.cave-ayland@ilande.co.uk> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 109.156.104.46 X-SA-Exim-Mail-From: mark.cave-ayland@ilande.co.uk Subject: [PATCH 4/4] esp: always check current_req is not NULL before use in DMA callbacks X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on mail.default.ilande.uk0.bigv.io) Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2001:41c9:1:41f::167; envelope-from=mark.cave-ayland@ilande.co.uk; helo=mail.default.ilande.uk0.bigv.io X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" After issuing a SCSI command the SCSI layer can call the SCSIBusInfo .cancel callback which resets both current_req and current_dev to NULL. If any data is left in the transfer buffer (async_len !=3D 0) then the next TI (Transfer Information) command will attempt to reference the NULL pointer causing a segfault. Buglink: https://bugs.launchpad.net/qemu/+bug/1910723 Buglink: https://bugs.launchpad.net/qemu/+bug/1909247 Signed-off-by: Mark Cave-Ayland --- hw/scsi/esp.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-) diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c index ae362c9dfb..7216903ce0 100644 --- a/hw/scsi/esp.c +++ b/hw/scsi/esp.c @@ -524,7 +524,9 @@ static void do_dma_pdma_cb(ESPState *s) } =20 if (s->async_len =3D=3D 0) { - scsi_req_continue(s->current_req); + if (s->current_req) { + scsi_req_continue(s->current_req); + } return; } =20 @@ -674,14 +676,16 @@ static void esp_do_dma(ESPState *s) s->ti_size -=3D len; } if (s->async_len =3D=3D 0) { - scsi_req_continue(s->current_req); - /* - * If there is still data to be read from the device then - * complete the DMA operation immediately. Otherwise defer - * until the scsi layer has completed. - */ - if (to_device || esp_get_tc(s) !=3D 0 || s->ti_size =3D=3D 0) { - return; + if (s->current_req) { + scsi_req_continue(s->current_req); + /* + * If there is still data to be read from the device then + * complete the DMA operation immediately. Otherwise defer + * until the scsi layer has completed. + */ + if (to_device || esp_get_tc(s) !=3D 0 || s->ti_size =3D=3D 0) { + return; + } } } =20 @@ -744,10 +748,12 @@ static void esp_do_nodma(ESPState *s) } =20 if (s->async_len =3D=3D 0) { - scsi_req_continue(s->current_req); + if (s->current_req) { + scsi_req_continue(s->current_req); =20 - if (to_device || s->ti_size =3D=3D 0) { - return; + if (to_device || s->ti_size =3D=3D 0) { + return; + } } } =20 --=20 2.20.1