Re: [PATCH 0/5] srcu fixes

Paul E. McKenney
2023-10-04T00:35:36Z

On Wed, Oct 04, 2023 at 01:28:58AM +0200, Frederic Weisbecker wrote:
> Hi,
>
> This contains a fix for "SRCU: kworker hung in synchronize_srcu":
>
> http://lore.kernel.org/CANZk6aR+CqZaqmMWrC2eRRPY12qAZnDZLwLnHZbNi=xXMB401g@mail.gmail.com
>
> And a few cleanups.
>
> Passed 50 hours of SRCU-P and SRCU-N.
>
> git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
> srcu/fixes
>
> HEAD: 7ea5adc5673b42ef06e811dca75e43d558cc87e0
>
> Thanks,
> Frederic

Very good, and a big "Thank You!!!" to all of you!

I queued this series for testing purposes, and have started a bunch of
SRCU-P and SRCU-N tests on one set of systems, and a single SRCU-P and
SRCU-N on another system, but with both scenarios resized to 40 CPU each.

While that is in flight, a few questions:

o Please check the Co-developed-by rules. Last I knew, it was
necessary to have a Signed-off-by after each Co-developed-by.

o Is it possible to get a Tested-by from the original reporter?
Or is this not reproducible?

o Is it possible to convince rcutorture to find this sort of
bug? Seems like it should be, but easy to say...

o Frederic, would you like to include this in your upcoming
pull request? Or does it need more time?

Thanx, Paul

> ---
>
> Frederic Weisbecker (5):
> srcu: Fix callbacks acceleration mishandling
> srcu: Only accelerate on enqueue time
> srcu: Remove superfluous callbacks advancing from srcu_start_gp()
> srcu: No need to advance/accelerate if no callback enqueued
> srcu: Explain why callbacks invocations can't run concurrently
>
>
> kernel/rcu/srcutree.c | 55 ++++++++++++++++++++++++++++++++++++---------------
> 1 file changed, 39 insertions(+), 16 deletions(-)