On Thu, Nov 17, 2016 at 10:04:46AM +0100, Peter Zijlstra wrote: > On Wed, Nov 16, 2016 at 10:48:28PM -0600, Josh Poimboeuf wrote: > > Peter or Vince, can you try to recreate with this patch? It dumps the > > raw stack contents during a stack dump. Hopefully that would give a > > clue about what's going wrong. > > > Here goes... I'll do another run and get you the results of that as > well.
Thanks, I just waded through this and it turned up some good clues. And according to 'git blame', you might be able to help :-) It's not stack corruption. Instead it looks like __intel_pmu_pebs_event() is creating a bad or stale pt_regs which gets passed to the unwinder. Specifically, regs->bp points to a seemingly random address on the NMI stack. Which seems odd, considering the code itself is running on the same NMI stack. I don't know much about the PEBS code but it seems like it's passing some stale data. Either that or there's some NMI nesting going on. -- Josh
