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=-20.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 E117FC07E9B for ; Mon, 5 Jul 2021 15:29:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CB59A61981 for ; Mon, 5 Jul 2021 15:29:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232311AbhGEPcD (ORCPT ); Mon, 5 Jul 2021 11:32:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:56354 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232218AbhGEPbq (ORCPT ); Mon, 5 Jul 2021 11:31:46 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 184ED6199C; Mon, 5 Jul 2021 15:29:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625498948; bh=p7ki6QLfwXV3JfZ6iMqIRhwhsOhjQbxlo8xW8Ckg5L0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=F1vtTLCie8u8q/m7xik+11m/xauFRM50SOq5oT7nFHO+0hgQVYDVT3DvNyxviIJOi kflbj2bmTr34xRF17xqU83K3DHWrJWSr3tlBKcb8qAWZxJ3EZQGXx9quTH6S/UQlOh WjZC9lw+X0zAZOFi9gYLlAfqZFnjQsgK+f36YdmNKzP+k734teCX1GUy/ehseMmUJT jPGneTrSnrY3mNyGIWNZxBoVfh/LEkBmG7dqXIhh0uvEVCctwrBMWs/YzmTsoZ/NKv C0zHxHsjjK5xFrA2eNu/dXH0KstpAorZaRips0LOKoca9t0gFfw0cpMVzfBabjPfbL 37RyxzomUzctA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Thiago Rafael Becker , Ronnie Sahlberg , Steve French , Sasha Levin , linux-cifs@vger.kernel.org, samba-technical@lists.samba.org Subject: [PATCH AUTOSEL 5.13 40/59] cifs: retry lookup and readdir when EAGAIN is returned. Date: Mon, 5 Jul 2021 11:27:56 -0400 Message-Id: <20210705152815.1520546-40-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210705152815.1520546-1-sashal@kernel.org> References: <20210705152815.1520546-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org From: Thiago Rafael Becker [ Upstream commit 6efa994e35a402ae4ae2161b6439c94b64816cee ] According to the investigation performed by Jacob Shivers at Red Hat, cifs_lookup and cifs_readdir leak EAGAIN when the user session is deleted on the server. Fix this issue by implementing a retry with limits, as is implemented in cifs_revalidate_dentry_attr. Reproducer based on the work by Jacob Shivers: ~~~ $ cat readdir-cifs-test.sh #!/bin/bash # Install and configure powershell and sshd on the windows # server as descibed in # https://docs.microsoft.com/en-us/windows-server/administration/openssh/openssh_overview # This script uses expect(1) USER=dude SERVER=192.168.0.2 RPATH=root PASS='password' function debug_funcs { for line in $@ ; do echo "func $line +p" > /sys/kernel/debug/dynamic_debug/control done } function setup { echo 1 > /proc/fs/cifs/cifsFYI debug_funcs wait_for_compound_request \ smb2_query_dir_first cifs_readdir \ compound_send_recv cifs_reconnect_tcon \ generic_ip_connect cifs_reconnect \ smb2_reconnect_server smb2_reconnect \ cifs_readv_from_socket cifs_readv_receive tcpdump -i eth0 -w cifs.pcap host 192.168.2.182 & sleep 5 dmesg -C } function test_call { if [[ $1 == 1 ]] ; then tracer="strace -tt -f -s 4096 -o trace-$(date -Iseconds).txt" fi # Change the command here to anything appropriate $tracer ls $2 > /dev/null res=$? if [[ $1 == 1 ]] ; then if [[ $res == 0 ]] ; then 1>&2 echo success else 1>&2 echo "failure ($res)" fi fi } mountpoint /mnt > /dev/null || mount -t cifs -o username=$USER,pass=$PASS //$SERVER/$RPATH /mnt test_call 0 /mnt/ /usr/bin/expect << EOF set timeout 60 spawn ssh $USER@$SERVER expect "yes/no" { send "yes\r" expect "*?assword" { send "$PASS\r" } } "*?assword" { send "$PASS\r" } expect ">" { send "powershell close-smbsession -force\r" } expect ">" { send "exit\r" } expect eof EOF sysctl -w vm.drop_caches=2 > /dev/null sysctl -w vm.drop_caches=2 > /dev/null setup test_call 1 /mnt/ ~~~ Signed-off-by: Thiago Rafael Becker Acked-by: Ronnie Sahlberg Signed-off-by: Steve French Signed-off-by: Sasha Levin --- fs/cifs/dir.c | 4 ++++ fs/cifs/smb2ops.c | 5 +++++ 2 files changed, 9 insertions(+) diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c index 6bcd3e8f7cda..7c641f9a3dac 100644 --- a/fs/cifs/dir.c +++ b/fs/cifs/dir.c @@ -630,6 +630,7 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry, struct inode *newInode = NULL; const char *full_path; void *page; + int retry_count = 0; xid = get_xid(); @@ -673,6 +674,7 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry, cifs_dbg(FYI, "Full path: %s inode = 0x%p\n", full_path, d_inode(direntry)); +again: if (pTcon->posix_extensions) rc = smb311_posix_get_inode_info(&newInode, full_path, parent_dir_inode->i_sb, xid); else if (pTcon->unix_ext) { @@ -687,6 +689,8 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry, /* since paths are not looked up by component - the parent directories are presumed to be good here */ renew_parental_timestamps(direntry); + } else if (rc == -EAGAIN && retry_count++ < 10) { + goto again; } else if (rc == -ENOENT) { cifs_set_time(direntry, jiffies); newInode = NULL; diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index b68ba92893b6..903de7449aa3 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -2325,6 +2325,7 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon, struct smb2_query_directory_rsp *qd_rsp = NULL; struct smb2_create_rsp *op_rsp = NULL; struct TCP_Server_Info *server = cifs_pick_channel(tcon->ses); + int retry_count = 0; utf16_path = cifs_convert_path_to_utf16(path, cifs_sb); if (!utf16_path) @@ -2372,10 +2373,14 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon, smb2_set_related(&rqst[1]); +again: rc = compound_send_recv(xid, tcon->ses, server, flags, 2, rqst, resp_buftype, rsp_iov); + if (rc == -EAGAIN && retry_count++ < 10) + goto again; + /* If the open failed there is nothing to do */ op_rsp = (struct smb2_create_rsp *)rsp_iov[0].iov_base; if (op_rsp == NULL || op_rsp->sync_hdr.Status != STATUS_SUCCESS) { -- 2.30.2