On Sat, 6 Apr 2019, Andy Lutomirski wrote: > On Fri, Apr 5, 2019 at 8:11 AM Thomas Gleixner <t...@linutronix.de> wrote: > > > > From: Andy Lutomirski <l...@kernel.org> > > > > The IRQ stack lives in percpu space, so an IRQ handler that overflows it > > will overwrite other data structures. > > > > Use vmap() to remap the IRQ stack so that it will have the usual guard > > pages that vmap/vmalloc allocations have. With this the kernel will panic > > immediately on an IRQ stack overflow. > > The 0day bot noticed that this dies with DEBUG_PAGEALLOC on. This is > because the store_stackinfo() function is utter garbage and this patch > correctly detects just how broken it is. The attached patch "fixes" > it. (It also contains a reliability improvement that should probably > get folded in, but is otherwise unrelated.) > > A real fix would remove the generic kstack_end() function entirely > along with __HAVE_ARCH_KSTACK_END and would optionally replace > store_stackinfo() with something useful. Josh, do we have a generic > API to do a little stack walk like this? Otherwise, I don't think it > would be the end of the world to just remove the offending code.
Actually we have: save_stack_trace()
