From patchwork Thu Feb 27 21:12:09 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Simmons X-Patchwork-Id: 11410077 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 35B95138D for ; Thu, 27 Feb 2020 21:29:41 +0000 (UTC) Received: from pdx1-mailman02.dreamhost.com (pdx1-mailman02.dreamhost.com [64.90.62.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1E94E246A1 for ; Thu, 27 Feb 2020 21:29:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1E94E246A1 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lustre-devel-bounces@lists.lustre.org Received: from pdx1-mailman02.dreamhost.com (localhost [IPv6:::1]) by pdx1-mailman02.dreamhost.com (Postfix) with ESMTP id 109823494BF; Thu, 27 Feb 2020 13:25:32 -0800 (PST) X-Original-To: lustre-devel@lists.lustre.org Delivered-To: lustre-devel-lustre.org@pdx1-mailman02.dreamhost.com Received: from smtp3.ccs.ornl.gov (smtp3.ccs.ornl.gov [160.91.203.39]) by pdx1-mailman02.dreamhost.com (Postfix) with ESMTP id 1627621FD84 for ; Thu, 27 Feb 2020 13:19:38 -0800 (PST) Received: from star.ccs.ornl.gov (star.ccs.ornl.gov [160.91.202.134]) by smtp3.ccs.ornl.gov (Postfix) with ESMTP id 62E842C78; Thu, 27 Feb 2020 16:18:16 -0500 (EST) Received: by star.ccs.ornl.gov (Postfix, from userid 2004) id 61C1B46A; Thu, 27 Feb 2020 16:18:16 -0500 (EST) From: James Simmons To: Andreas Dilger , Oleg Drokin , NeilBrown Date: Thu, 27 Feb 2020 16:12:09 -0500 Message-Id: <1582838290-17243-262-git-send-email-jsimmons@infradead.org> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1582838290-17243-1-git-send-email-jsimmons@infradead.org> References: <1582838290-17243-1-git-send-email-jsimmons@infradead.org> Subject: [lustre-devel] [PATCH 261/622] lnet: Avoid lnet debugfs read/write if ctl_table does not exist X-BeenThere: lustre-devel@lists.lustre.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "For discussing Lustre software development." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Lustre Development List MIME-Version: 1.0 Errors-To: lustre-devel-bounces@lists.lustre.org Sender: "lustre-devel" From: Sonia Sharma Running command "lctl get param -n stats" after lnet is taken down leads to kernel panic because it tries to read from the file which doesn't exist anymore. In lnet_debugfs_read() and lnet_debugfs_write(), check if struct ctl_table is valid before trying to read/write to it. WC-bug-id: https://jira.whamcloud.com/browse/LU-11986 Lustre-commit: 54ca5e471d9f ("LU-11986 lnet: Avoid lnet debugfs read/write if ctl_table does not exist") Signed-off-by: Sonia Sharma Reviewed-on: https://review.whamcloud.com/34634 Reviewed-by: James Simmons Reviewed-by: Oleg Drokin Signed-off-by: James Simmons --- net/lnet/libcfs/module.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/net/lnet/libcfs/module.c b/net/lnet/libcfs/module.c index bee2581..37a3fee 100644 --- a/net/lnet/libcfs/module.c +++ b/net/lnet/libcfs/module.c @@ -597,9 +597,11 @@ static ssize_t lnet_debugfs_read(struct file *filp, char __user *buf, { struct ctl_table *table = filp->private_data; loff_t old_pos = *ppos; - ssize_t rc; + ssize_t rc = -EINVAL; - rc = table->proc_handler(table, 0, (void __user *)buf, &count, ppos); + if (table) + rc = table->proc_handler(table, 0, (void __user *)buf, + &count, ppos); /* * On success, the length read is either in error or in count. * If ppos changed, then use count, else use error @@ -617,9 +619,11 @@ static ssize_t lnet_debugfs_write(struct file *filp, const char __user *buf, { struct ctl_table *table = filp->private_data; loff_t old_pos = *ppos; - ssize_t rc; + ssize_t rc = -EINVAL; - rc = table->proc_handler(table, 1, (void __user *)buf, &count, ppos); + if (table) + rc = table->proc_handler(table, 1, (void __user *)buf, &count, + ppos); if (rc) return rc;