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 amdtpdomainstreampcmpointer() and updatepcmpointers() 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 sndpcmstreamlockirq() in sndpcmstatus64() * (lock B) wait for tasklet to finish by calling taskletunlockspinwait() in taskletdisableinatomic() in ohciflushiso_completions() of ohci.c

thread 1: * (lock B) enter tasklet * (lock A) attempt to acquire substream lock, waiting for it to be released: sndpcmstreamlockirqsave() in sndpcmperiodelapsed() in updatepcmpointers() in processctxpayloads() in processrx_packets() of amdtp-stream.c

? taskletunlockspinwait </NMI> <TASK> ohciflushisocompletions firewireohci amdtpdomainstreampcmpointer sndfirewirelib sndpcmupdatehwptr0 sndpcm sndpcmstatus64 snd_pcm

? nativequeuedspinlockslowpath </NMI> <IRQ> rawspinlockirqsave sndpcmperiodelapsed sndpcm processrxpackets sndfirewirelib irqtargetcallback sndfirewirelib handleitpacket firewireohci contexttasklet firewire_ohci

Restore the process context work queue to prevent deadlock AB/BA deadlock competition for ALSA substream lock of sndpcmstreamlockirq() in sndpcmstatus64() and sndpcmstreamlockirqsave() in sndpcmperiod_elapsed().

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

Replace inline description to prevent future deadlock.