CVE-2024-56531

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ALSA: caiaq: Use snd_card_free_when_closed() at disconnection<br /> <br /> The USB disconnect callback is supposed to be short and not too-long<br /> waiting. OTOH, the current code uses snd_card_free() at<br /> disconnection, but this waits for the close of all used fds, hence it<br /> can take long. It eventually blocks the upper layer USB ioctls, which<br /> may trigger a soft lockup.<br /> <br /> An easy workaround is to replace snd_card_free() with<br /> snd_card_free_when_closed(). This variant returns immediately while<br /> the release of resources is done asynchronously by the card device<br /> release at the last close.<br /> <br /> This patch also splits the code to the disconnect and the free phases;<br /> the former is called immediately at the USB disconnect callback while<br /> the latter is called from the card destructor.