On Fri, Feb 21, 2020 at 10:08:43PM -0500, Joel Fernandes wrote: > On Fri, Feb 21, 2020 at 02:34:17PM +0100, Peter Zijlstra wrote: > > nmi_enter() does lockdep_off() and hence lockdep ignores everything. > > > > And NMI context makes it impossible to do full IN-NMI tracking like we > > do IN-HARDIRQ, that could result in graph_lock recursion. > > The patch makes sense to me. > > Reviewed-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx> > > NOTE: > Also, I was wondering if we can detect the graph_lock recursion case and > avoid doing anything bad, that way we enable more of the lockdep > functionality for NMI where possible. Not sure if the suggestion makes sense > though! Yeah, I considered playing trylock games, but figured I shouldn't make it more complicated that it needs to be.
