DEBIAN-CVE-2025-71221

In the Linux kernel, the following vulnerability has been resolved:  dmaengine: mmppdma: Fix race condition in mmppdmaresidue()  Add proper locking in mmppdmaresidue() to prevent use-after-free when accessing descriptor list and descriptor contents.  The race occurs when multiple threads call txstatus() while the tasklet on another CPU is freeing completed descriptors:  CPU 0                              CPU 1 -----                              ----- mmppdmatxstatus() mmppdmaresidue()   -> NO LOCK held      listforeachentry(sw, ..)                                    DMA interrupt                                    dmadotasklet()                                      -> spinlock(&desclock)                                         listmove(sw->node, ...)                                         spinunlock(&desclock)   |                                     dmapoolfree(sw) <- FREED!   -> access sw->desc <- UAF!  This issue can be reproduced when running dmatest on the same channel with multiple threads (threadsperchan > 1).  Fix by protecting the chainrunning list iteration and descriptor access with the chan->desc_lock spinlock.