d5a4f93511
The port->logbuffer_head may be wrong if the two processes enters _tcpm_log at the mostly same time. The 2nd process enters _tcpm_log before the 1st process update the index, then the 2nd process will not allocate logbuffer, when the 2nd process tries to use log buffer, the index has already updated by the 1st process, so it will get NULL pointer for updated logbuffer, the error message like below: tcpci 0-0050: Log buffer index 6 is NULL Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Jun Li <jun.li@nxp.com> Signed-off-by: Peter Chen <peter.chen@nxp.com> Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Cc: stable <stable@vger.kernel.org> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
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.