On Wed, May 29, 2019 at 10:02:43PM +0100, David Howells wrote: > Jann Horn <jannh@xxxxxxxxxx> wrote: > > > Does this mean that refcount_read() isn't sufficient for what you want > > to do with tracing (because for some reason you actually need to know > > the values atomically at the time of increment/decrement)? > > Correct. There's a gap and if an interrupt or something occurs, it's > sufficiently big for the refcount trace to go weird. > > I've seen it in afs/rxrpc where the incoming network packets that are part of > the rxrpc call flow disrupt the refcounts noted in trace lines. Can you re-iterate the exact problem? I konw we talked about this in the past, but I seem to have misplaced those memories :/ FWIW I agree that kref is useless fluff, but I've long ago given up on that fight.
