CVE-2024-42274

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> Revert "ALSA: firewire-lib: operate for period elapse event in process context"<br /> <br /> Commit 7ba5ca32fe6e ("ALSA: firewire-lib: operate for period elapse event<br /> in process context") removed the process context workqueue from<br /> amdtp_domain_stream_pcm_pointer() and update_pcm_pointers() to remove<br /> its overhead.<br /> <br /> With RME Fireface 800, this lead to a regression since<br /> Kernels 5.14.0, causing an AB/BA deadlock competition for the<br /> substream lock with eventual system freeze under ALSA operation:<br /> <br /> thread 0:<br /> * (lock A) acquire substream lock by<br /> snd_pcm_stream_lock_irq() in<br /> snd_pcm_status64()<br /> * (lock B) wait for tasklet to finish by calling<br /> tasklet_unlock_spin_wait() in<br /> tasklet_disable_in_atomic() in<br /> ohci_flush_iso_completions() of ohci.c<br /> <br /> thread 1:<br /> * (lock B) enter tasklet<br /> * (lock A) attempt to acquire substream lock,<br /> waiting for it to be released:<br /> snd_pcm_stream_lock_irqsave() in<br /> snd_pcm_period_elapsed() in<br /> update_pcm_pointers() in<br /> process_ctx_payloads() in<br /> process_rx_packets() of amdtp-stream.c<br /> <br /> ? tasklet_unlock_spin_wait<br /> <br /> <br /> ohci_flush_iso_completions firewire_ohci<br /> amdtp_domain_stream_pcm_pointer snd_firewire_lib<br /> snd_pcm_update_hw_ptr0 snd_pcm<br /> snd_pcm_status64 snd_pcm<br /> <br /> ? native_queued_spin_lock_slowpath<br /> <br /> <br /> _raw_spin_lock_irqsave<br /> snd_pcm_period_elapsed snd_pcm<br /> process_rx_packets snd_firewire_lib<br /> irq_target_callback snd_firewire_lib<br /> handle_it_packet firewire_ohci<br /> context_tasklet firewire_ohci<br /> <br /> Restore the process context work queue to prevent deadlock<br /> AB/BA deadlock competition for ALSA substream lock of<br /> snd_pcm_stream_lock_irq() in snd_pcm_status64()<br /> and snd_pcm_stream_lock_irqsave() in snd_pcm_period_elapsed().<br /> <br /> revert commit 7ba5ca32fe6e ("ALSA: firewire-lib: operate for period<br /> elapse event in process context")<br /> <br /> Replace inline description to prevent future deadlock.