From patchwork Thu Apr 1 07:49:23 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Cave-Ayland X-Patchwork-Id: 1460878 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4F9wMz1xqPz9sV5 for ; Thu, 1 Apr 2021 18:50:39 +1100 (AEDT) Received: from localhost ([::1]:58342 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lRs69-0005F9-8P for incoming@patchwork.ozlabs.org; Thu, 01 Apr 2021 03:50:37 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56920) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lRs5Q-0005DW-RK for qemu-devel@nongnu.org; Thu, 01 Apr 2021 03:49:52 -0400 Received: from mail.ilande.co.uk ([2001:41c9:1:41f::167]:56998 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 1lRs5P-0000fh-A5 for qemu-devel@nongnu.org; Thu, 01 Apr 2021 03:49:52 -0400 Received: from host86-148-103-9.range86-148.btcentralplus.com ([86.148.103.9] 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 1lRs5S-0004IO-72; Thu, 01 Apr 2021 08:50:01 +0100 From: Mark Cave-Ayland To: qemu-devel@nongnu.org, alxndr@bu.edu, laurent@vivier.eu, pbonzini@redhat.com Date: Thu, 1 Apr 2021 08:49:23 +0100 Message-Id: <20210401074933.9923-2-mark.cave-ayland@ilande.co.uk> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210401074933.9923-1-mark.cave-ayland@ilande.co.uk> References: <20210401074933.9923-1-mark.cave-ayland@ilande.co.uk> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 86.148.103.9 X-SA-Exim-Mail-From: mark.cave-ayland@ilande.co.uk Subject: [PATCH v3 01/11] 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 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+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" 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 != 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 | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c index 507ab363bc..bafea0d4e6 100644 --- a/hw/scsi/esp.c +++ b/hw/scsi/esp.c @@ -496,6 +496,10 @@ static void do_dma_pdma_cb(ESPState *s) return; } + if (!s->current_req) { + return; + } + if (to_device) { /* Copy FIFO data to device */ len = MIN(s->async_len, ESP_FIFO_SZ); @@ -527,11 +531,9 @@ static void do_dma_pdma_cb(ESPState *s) return; } else { if (s->async_len == 0) { - if (s->current_req) { - /* Defer until the scsi layer has completed */ - scsi_req_continue(s->current_req); - s->data_in_ready = false; - } + /* Defer until the scsi layer has completed */ + scsi_req_continue(s->current_req); + s->data_in_ready = false; return; } @@ -604,6 +606,9 @@ static void esp_do_dma(ESPState *s) } return; } + if (!s->current_req) { + return; + } if (s->async_len == 0) { /* Defer until data is available. */ return; @@ -713,6 +718,10 @@ static void esp_do_nodma(ESPState *s) return; } + if (!s->current_req) { + return; + } + if (s->async_len == 0) { /* Defer until data is available. */ return;