On Sun, 23 Jun 2019, Akira Yokosawa wrote: > Hi Paul and Alan, > > On 2019/06/22 8:54, Paul E. McKenney wrote: > > On Fri, Jun 21, 2019 at 10:25:23AM -0400, Alan Stern wrote: > >> On Fri, 21 Jun 2019, Andrea Parri wrote: > >> > >>> On Thu, Jun 20, 2019 at 11:55:58AM -0400, Alan Stern wrote: > >>>> Herbert Xu recently reported a problem concerning RCU and compiler > >>>> barriers. In the course of discussing the problem, he put forth a > >>>> litmus test which illustrated a serious defect in the Linux Kernel > >>>> Memory Model's data-race-detection code. > > I was not involved in the mail thread and wondering what the litmus test > looked like. Some searching of the archive has suggested that Alan presented > a properly formatted test based on Herbert's idea in [1]. > > [1]: > https://lore.kernel.org/lkml/[email protected]/
Yes, that's it. The test is also available at: https://github.com/paulmckrcu/litmus/blob/master/manual/plain/C-S-rcunoderef-2.litmus Alan > If this is the case, adding the link (or message id) in the change > log would help people see the circumstances, I suppose. > Paul, can you amend the change log? > > I ran herd7 on said litmus test at both "lkmm" and "dev" of -rcu and > confirmed that this patch fixes the result. > > So, > > Tested-by: Akira Yokosawa <[email protected]> > > Thanks, Akira
