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ALSA timer may reallocate the user queue upon request, and it happens at three places for now: at opening, at SNDRV_TIMER_IOCTL_PARAMS, and at SNDRV_TIMER_IOCTL_SELECT. However, the last one, snd_timer_user_tselect(), doesn't need to reallocate the buffer since it doesn't change the queue size. It does just because tu->tread might have been changed before starting the timer. Instead of *_SELECT ioctl, we should reallocate the queue at SNDRV_TIMER_IOCTL_TREAD; then the timer is guaranteed to be stopped, thus we can reassign the buffer more safely. This patch implements that with a slight code refactoring. Essentially, the patch achieves: - Introduce realloc_user_queue() for (re-)allocating the ring buffer, and call it from all places. Also, realloc_user_queue() uses kcalloc() for avoiding possible leaks. - Add the buffer reallocation at SNDRV_TIMER_IOCTL_TREAD. When it fails, tu->tread is restored to the old value, too. - Drop the buffer reallocation at snd_timer_user_tselect(). Tested-by: Alexander Potapenko <glider@google.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
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.