Re: [PATCH] ALSA: usb-audio: endpoint : remove redundant check before usb_free_coherent()

On Thu, 04 Feb 2021 03:05:18 +0100, Xu Wang wrote:

usb_free_coherent() is safe with NULL addr and this check is not required.

The check there isn't about NULL buffer or not; instead it checks whether the buffer was allocated for each or it shares the single buffer (for sync endpoints). In the latter case, your patch will lead to double-free.

thanks,

Takashi