On Thu, Jul 29, 2021 at 12:24 AM Daniel Vetter <daniel@xxxxxxxx> wrote: > > On Thu, Jul 29, 2021 at 09:03:30AM +0200, Christian König wrote: > > As we now knew controlling dma_fence synchronization from userspace is > > extremely dangerous and can not only deadlock drivers but trivially also the > > whole kernel memory management. > > > > Entirely remove this option. We now have in kernel unit tests to exercise the > > dma_fence framework and it's containers. > > > > Signed-off-by: Christian König <christian.koenig@xxxxxxx> > > There's also igts for this, and Android heavily uses this. So I'm not sure > we can just nuke it. Eeeeh... I don't think that's actually the case anymore. As of android12-5.10 CONFIG_SW_SYNC is not turned on. Further, Android is disabling debugfs in their kernels as it exposes too much to userland. That said, there still are some references to it: https://cs.android.com/android/platform/superproject/+/master:system/core/libsync/sync.c;l=416 But it looks like the actual users are only kselftest and igt? Adding Alistair, Hridya and Sandeep in case they have more context. thanks -john
