28cada984c
commit 7ffbe65578b44fafdef577a360eb0583929f7c6e upstream. For every request we send, whether it is SMB1 or SMB2+, we attempt to reconnect tcon (cifs_reconnect_tcon or smb2_reconnect) before carrying out the request. So, while server->tcpStatus != CifsNeedReconnect, we wait for the reconnection to succeed on wait_event_interruptible_timeout(). If it returns, that means that either the condition was evaluated to true, or timeout elapsed, or it was interrupted by a signal. Since we're not handling the case where the process woke up due to a received signal (-ERESTARTSYS), the next call to wait_event_interruptible_timeout() will _always_ fail and we end up looping forever inside either cifs_reconnect_tcon() or smb2_reconnect(). Here's an example of how to trigger that: $ mount.cifs //foo/share /mnt/test -o username=foo,password=foo,vers=1.0,hard (break connection to server before executing bellow cmd) $ stat -f /mnt/test & sleep 140 [1] 2511 $ ps -aux -q 2511 USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 2511 0.0 0.0 12892 1008 pts/0 S 12:24 0:00 stat -f /mnt/test $ kill -9 2511 (wait for a while; process is stuck in the kernel) $ ps -aux -q 2511 USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 2511 83.2 0.0 12892 1008 pts/0 R 12:24 30:01 stat -f /mnt/test By using 'hard' mount point means that cifs.ko will keep retrying indefinitely, however we must allow the process to be killed otherwise it would hang the system. Signed-off-by: Paulo Alcantara <palcantara@suse.de> Cc: stable@vger.kernel.org Reviewed-by: Aurelien Aptel <aaptel@suse.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.