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When cursor is at beginning of an empty or whitespace-only line and speakup-r typed, kernel locks up. This happens because deadlock of in input_event function over dev->event_lock, as demonstrated by lockdep logs. The reason for that is speakup simulates a down arrow - because cursor is at an empty line - while inside key press notifier handler which is ultimately triggered from input_event function. The simulated key press leads to input_event being called again, this time under its own context. So the spinlock is dev->event_lock is acquired while still being held. This patch ensures that key press is not simulated from inside key press notifier handler. Instead it delegates to cursor_timer. It starts the timer and passes RA_DOWN_ARROW as argument. When timer handler runs and sees RA_DOWN_ARROW, it will then call kbd_fakekey2(RA_DOWN_ARROW) which will correctly simulate the keypress inside timer context. When not inside key press notifier callback, the behaviour will remain the same as before this patch. Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> 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.