From nobody Wed Nov 19 14:13:37 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=1616022647; cv=none; d=zohomail.com; s=zohoarc; b=hdemtRotrcxlB63BY56WqGKBHxxqoXgPUC+guHfTukElSqzu093Qm5uOnFurFekRm2ry8aURTOrRSU5nk4JqlIe7XGD9Ko8guhN7e3sJQm/1gDc9/o8MfeR5qxanqNvHhI/brFVx9y4rU1AcCeu+/hz1awJXvZXgPYw5sDFN3tg= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1616022647; 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=7z+k2rAYgmzYQblYdJVVUa6JQlNlYI3A9fUvimjPTTs=; b=jD6q4rvkWCL/v2NS927TOVaSdj6Ut0GEfhIfTeiBaUO0XzZsm6bjlxfaR6sirsl8+fXX3ICRl7AY7l9PM647sjvLrHUEaD/4pCOqQs5BTUwWJfvSZqyPClTgHBQ/j09dAGv02a1BoYefMdlD7g8JaPVGLfluNwOPkxHtQMXlhB0= 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 161602264711497.61340820930502; Wed, 17 Mar 2021 16:10:47 -0700 (PDT) Received: from localhost ([::1]:55764 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lMfJN-0008TV-OO for importer@patchew.org; Wed, 17 Mar 2021 19:10:45 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43570) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lMfBu-0002pd-Oh for qemu-devel@nongnu.org; Wed, 17 Mar 2021 19:03:02 -0400 Received: from mail.ilande.co.uk ([2001:41c9:1:41f::167]:35410 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 1lMfBs-0005TR-UC for qemu-devel@nongnu.org; Wed, 17 Mar 2021 19:03:02 -0400 Received: from host86-148-103-84.range86-148.btcentralplus.com ([86.148.103.84] 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 1lMfBs-0006Bn-E9; Wed, 17 Mar 2021 23:03:05 +0000 From: Mark Cave-Ayland To: qemu-devel@nongnu.org, alxndr@bu.edu, laurent@vivier.eu, pbonzini@redhat.com Date: Wed, 17 Mar 2021 23:02:22 +0000 Message-Id: <20210317230223.24854-6-mark.cave-ayland@ilande.co.uk> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210317230223.24854-1-mark.cave-ayland@ilande.co.uk> References: <20210317230223.24854-1-mark.cave-ayland@ilande.co.uk> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 86.148.103.84 X-SA-Exim-Mail-From: mark.cave-ayland@ilande.co.uk Subject: [PATCH v2 5/6] 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 Tested-by: Alexander Bulekov --- 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 bb57125035..d7b81b7608 100644 --- a/hw/scsi/esp.c +++ b/hw/scsi/esp.c @@ -505,6 +505,10 @@ static void do_dma_pdma_cb(ESPState *s) return; } =20 + if (!s->current_req) { + return; + } + if (to_device) { /* Copy FIFO data to device */ len =3D MIN(s->async_len, ESP_FIFO_SZ); @@ -538,11 +542,9 @@ static void do_dma_pdma_cb(ESPState *s) return; } else { if (s->async_len =3D=3D 0) { - if (s->current_req) { - /* Defer until the scsi layer has completed */ - scsi_req_continue(s->current_req); - s->data_in_ready =3D false; - } + /* Defer until the scsi layer has completed */ + scsi_req_continue(s->current_req); + s->data_in_ready =3D false; return; } =20 @@ -616,6 +618,9 @@ static void esp_do_dma(ESPState *s) } return; } + if (!s->current_req) { + return; + } if (s->async_len =3D=3D 0) { /* Defer until data is available. */ return; @@ -725,6 +730,10 @@ static void esp_do_nodma(ESPState *s) return; } =20 + if (!s->current_req) { + return; + } + if (s->async_len =3D=3D 0) { /* Defer until data is available. */ return; --=20 2.20.1