On Tue, Jun 26, 2018 at 02:53:06PM -0700, Joel Fernandes wrote:
> On Tue, Jun 26, 2018 at 03:53:49PM +0800, kernel test robot wrote:
> > Greetings,
> > 0day kernel testing robot got the below dmesg and the first bad commit is
> > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> > commit 173fb50cb6e99b86f5c67a0220a8b1a75f5c1f67
> > Author: Joel Fernandes (Google) <joel(a)joelfernandes.org>
> > AuthorDate: Sun Jun 10 16:45:44 2018 -0700
> > Commit: Paul E. McKenney <paulmck(a)linux.vnet.ibm.com>
> > CommitDate: Wed Jun 20 07:44:37 2018 -0700
> > rcutorture: Make boost test more robust
> > Currently, with RCU_BOOST disabled, I get no failures when forcing
> > rcutorture to test RCU boost priority inversion. The reason seems to be
> > that we don't check for failures if the callback never ran at all for
> > the duration of the boost-test loop.
> > Further, the 'rtb' and 'rtbf' counters seem to be used inconsistently.
> > 'rtb' is incremented at the start of each test and 'rtbf' is incremented
> > per-cpu on each failure of call_rcu. So its possible 'rtbf' > 'rtb'.
> > To test the boost with rcutorture, I did following on a 4-CPU x86 machine:
> > modprobe rcutorture test_boost=2
> > sleep 20
> > rmmod rcutorture
> > With patch:
> > rtbf: 8 rtb: 12
> > Without patch:
> > rtbf: 0 rtb: 2
> > In summary this patch:
> > - Increments failed and total test counters once per boost-test.
> > - Checks for failure cases correctly.
> > Signed-off-by: Joel Fernandes (Google) <joel(a)joelfernandes.org>
> > Signed-off-by: Paul E. McKenney <paulmck(a)linux.vnet.ibm.com>
> This -next tree seems to be missing this patch:
> 7e9736664ada rcu: Assign higher prio to RCU threads if rcutorture is built-in
> Paul's rcu/next tree already has this patch. I think this reported issue will
> go away once Paul's rcu/next tree is pulled.
Which is updated again, so hopefully this should be taken care of. ;-)