On Wed, May 29, 2019 at 07:03:13PM +0200, Peter Zijlstra wrote: > On Wed, May 29, 2019 at 05:38:54PM +0100, Mark Rutland wrote: > > Generally speaking though, if we ever task task_pt_regs() of an idle > > task we'll get junk, and user_mode() could be true. > > Agreed, but we're not doing that.
Sure. I just think that might be an argument for having task_pt_regs() return NULL for kthreads, or having a WARN_ON_ONCE(t->flags & PF_KTHREAD) to catch missing checks elsewhere. Thanks, Mark.