N/A - CVE-2024-42274

In the Linux kernel, the following vulnerability has been resolved:

Revert "ALSA: firewire-lib: operate for period elapse event in process context"

Commit 7ba5ca32fe6e ("ALSA: firewire-lib: operate for period elapse event in process context") removed the process context workqueue from amdtp_domain_stream_pcm_pointer() and update_pcm_pointers() to remove its overhead.

With RME Fireface 800, this lead to a regression since Kernels 5.14.0, causing an AB/BA deadlock competition for the substream lock with eventual system freeze under ALSA operation:

thread 0:
* (lock A) acquire substream lock by
snd_pcm_stream_lock_irq() in
snd_pcm_status64()
* (lock B) wait for tasklet to finish by calling
tasklet_unlock_spin_wait() in
tasklet_disable_in_atomic() in
ohci_flush_iso_completions() of ohci.c

thread 1:
* (lock B) enter tasklet
* (lock A) attempt to acquire substream lock,
waiting for it to be released:
snd_pcm_stream_lock_irqsave() in
snd_pcm_period_elapsed() in
update_pcm_pointers() in
process_ctx_payloads() in
process_rx_packets() of amdtp-stream.c

? tasklet_unlock_spin_wait

ohci_flush_iso_completions firewire_ohci amdtp_domain_stream_pcm_pointer snd_firewire_lib snd_pcm_update_hw_ptr0 snd_pcm snd_pcm_status64 snd_pcm

? native_queued_spin_lock_slowpath

_raw_spin_lock_irqsave snd_pcm_period_elapsed snd_pcm process_rx_packets snd_firewire_lib irq_target_callback snd_firewire_lib handle_it_packet firewire_ohci context_tasklet firewire_ohci

Restore the process context work queue to prevent deadlock AB/BA deadlock competition for ALSA substream lock of snd_pcm_stream_lock_irq() in snd_pcm_status64() and snd_pcm_stream_lock_irqsave() in snd_pcm_period_elapsed().

revert commit 7ba5ca32fe6e ("ALSA: firewire-lib: operate for period elapse event in process context")

Replace inline description to prevent future deadlock.