f743061a85
The comment near to uart_port_spin_lock_init() says: Ensure that the serial console lock is initialised early. If this port is a console, then the spinlock is already initialised. and there is nothing about enabled or disabled consoles. The commita3cb39d258("serial: core: Allow detach and attach serial device for console") made a change, which follows the comment, and also to prevent reinitialisation of the lock in use, when user detaches and attaches back the same console device. But this change discovers another issue, that uart_add_one_port() tries to access a spin lock that now may be uninitialised. This happens when a driver expects the serial core to register a console on its behalf. In this case we must initialise a spin lock before use. Fixes:a3cb39d258("serial: core: Allow detach and attach serial device for console") Reported-by: Marc Zyngier <maz@kernel.org> Reported-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> Reported-by: Guenter Roeck <linux@roeck-us.net> Reported-by: Anatoly Pugachev <matorola@gmail.com> Acked-by: Marc Zyngier <maz@kernel.org> Tested-by: Tony Lindgren <tony@atomide.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> Link: https://lore.kernel.org/r/20200706214903.56148-1-andriy.shevchenko@linux.intel.com 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.
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.