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=-13.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 87046C4363D for ; Mon, 5 Oct 2020 15:27:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4F217208B6 for ; Mon, 5 Oct 2020 15:27:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601911634; bh=TVjdzA8A4qh+hbFHWkyB9LfVKMPoF7AJk4WcfA3JS7M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=t1TrOMOetx5mtQUoqo7WoBQYRr7TBm7kK/UpUlr07pnagOIsU5ZRe3L99a/qOXhnG 50DVYgF1mGeQgOF6TsYvNe0eqzx0GjU9ePFN4EOai9LoI7H+jQV5SjAtTX2napdQ2/ iL9MmDkF318A4pWWLPQc0NMG/z3lIdlTuPBReUWs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727192AbgJEP1N (ORCPT ); Mon, 5 Oct 2020 11:27:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:51596 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727146AbgJEP1J (ORCPT ); Mon, 5 Oct 2020 11:27:09 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4D10D20874; Mon, 5 Oct 2020 15:27:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601911628; bh=TVjdzA8A4qh+hbFHWkyB9LfVKMPoF7AJk4WcfA3JS7M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eZ3ZeTNsEjrzPV6zY2gM7O02K13fi6E0bXklwlDTEdQHnzLKw0f0tlMr7YuiiSQ3P fpe6g3I51EsXMGYNcB8YpN9YV2QygitsYujqDWmvPcuoJ46AFkdBjdTp18FIwEbLnf o7t19yQcvF8ap3SlMNLwZEgCJ0GdxqKBT4RYIi5g= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chaitanya Kulkarni , Christoph Hellwig , Sasha Levin Subject: [PATCH 4.19 17/38] nvme-core: get/put ctrl and transport module in nvme_dev_open/release() Date: Mon, 5 Oct 2020 17:26:34 +0200 Message-Id: <20201005142109.502047700@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201005142108.650363140@linuxfoundation.org> References: <20201005142108.650363140@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Chaitanya Kulkarni [ Upstream commit 52a3974feb1a3eec25d8836d37a508b67b0a9cd0 ] Get and put the reference to the ctrl in the nvme_dev_open() and nvme_dev_release() before and after module get/put for ctrl in char device file operations. Introduce char_dev relase function, get/put the controller and module which allows us to fix the potential Oops which can be easily reproduced with a passthru ctrl (although the problem also exists with pure user access): Entering kdb (current=0xffff8887f8290000, pid 3128) on processor 30 Oops: (null) due to oops @ 0xffffffffa01019ad CPU: 30 PID: 3128 Comm: bash Tainted: G W OE 5.8.0-rc4nvme-5.9+ #35 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.4 RIP: 0010:nvme_free_ctrl+0x234/0x285 [nvme_core] Code: 57 10 a0 e8 73 bf 02 e1 ba 3d 11 00 00 48 c7 c6 98 33 10 a0 48 c7 c7 1d 57 10 a0 e8 5b bf 02 e1 8 RSP: 0018:ffffc90001d63de0 EFLAGS: 00010246 RAX: ffffffffa05c0440 RBX: ffff8888119e45a0 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff8888177e9550 RDI: ffff8888119e43b0 RBP: ffff8887d4768000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffc90001d63c90 R12: ffff8888119e43b0 R13: ffff8888119e5108 R14: dead000000000100 R15: ffff8888119e5108 FS: 00007f1ef27b0740(0000) GS:ffff888817600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffa05c0470 CR3: 00000007f6bee000 CR4: 00000000003406e0 Call Trace: device_release+0x27/0x80 kobject_put+0x98/0x170 nvmet_passthru_ctrl_disable+0x4a/0x70 [nvmet] nvmet_passthru_enable_store+0x4c/0x90 [nvmet] configfs_write_file+0xe6/0x150 vfs_write+0xba/0x1e0 ksys_write+0x5f/0xe0 do_syscall_64+0x52/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f1ef1eb2840 Code: Bad RIP value. RSP: 002b:00007fffdbff0eb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f1ef1eb2840 RDX: 0000000000000002 RSI: 00007f1ef27d2000 RDI: 0000000000000001 RBP: 00007f1ef27d2000 R08: 000000000000000a R09: 00007f1ef27b0740 R10: 0000000000000001 R11: 0000000000000246 R12: 00007f1ef2186400 R13: 0000000000000002 R14: 0000000000000001 R15: 0000000000000000 With this patch fix we take the module ref count in nvme_dev_open() and release that ref count in newly introduced nvme_dev_release(). Signed-off-by: Chaitanya Kulkarni Signed-off-by: Christoph Hellwig Signed-off-by: Sasha Levin --- drivers/nvme/host/core.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 33dad9774da01..9ea3d8e611005 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -2605,10 +2605,24 @@ static int nvme_dev_open(struct inode *inode, struct file *file) return -EWOULDBLOCK; } + nvme_get_ctrl(ctrl); + if (!try_module_get(ctrl->ops->module)) + return -EINVAL; + file->private_data = ctrl; return 0; } +static int nvme_dev_release(struct inode *inode, struct file *file) +{ + struct nvme_ctrl *ctrl = + container_of(inode->i_cdev, struct nvme_ctrl, cdev); + + module_put(ctrl->ops->module); + nvme_put_ctrl(ctrl); + return 0; +} + static int nvme_dev_user_cmd(struct nvme_ctrl *ctrl, void __user *argp) { struct nvme_ns *ns; @@ -2669,6 +2683,7 @@ static long nvme_dev_ioctl(struct file *file, unsigned int cmd, static const struct file_operations nvme_dev_fops = { .owner = THIS_MODULE, .open = nvme_dev_open, + .release = nvme_dev_release, .unlocked_ioctl = nvme_dev_ioctl, .compat_ioctl = nvme_dev_ioctl, }; -- 2.25.1