ALSA: us122l: Use snd_card_free_when_closed() at disconnection

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: us122l: Use snd_card_free_when_closed() at disconnection The USB disconnect callback is supposed to be short and not too-long waiting. OTOH, the current code uses snd_card_free() at disconnection, but this waits for the close of all used fds, hence it can take long. It eventually blocks the upper layer USB ioctls, which may trigger a soft lockup. An easy workaround is to replace snd_card_free() with snd_card_free_when_closed(). This variant returns immediately while the release of resources is done asynchronously by the card device release at the last close. The loop of us122l->mmap_count check is dropped as well. The check is useless for the asynchronous operation with *_when_closed().

References

• https://git.kernel.org/stable/c/020cbc4d7414f0962004213e2b7bc5cc607e9ec7
• https://git.kernel.org/stable/c/75f418b249d84021865eaa59515d3ed9b75ce4d6
• https://git.kernel.org/stable/c/bf0aa35a7cb8602cccf2387712114e836f65c154
• https://git.kernel.org/stable/c/9a48bd2184b142c92a4e17eac074c61fcf975bc9
• https://git.kernel.org/stable/c/bc778ad3e495333eebda36fe91d5b2c93109cc16
• https://git.kernel.org/stable/c/2938dd2648522336133c151dd67bb9bf01cbd390
• https://git.kernel.org/stable/c/9b27924dc8d7f8a8c35e521287d4ccb9a006e597
• https://git.kernel.org/stable/c/9d5c530e4d70f64b1114f2cc29ac690ba7ac4a38
• https://git.kernel.org/stable/c/b7df09bb348016943f56b09dcaafe221e3f73947