On Wed, Oct 07, 2020 at 09:50:35AM +0800, Junchang Wang wrote:
> On Tue, Oct 06, 2020 at 08:41:49AM -0700, Paul E. McKenney wrote:
> >On Tue, Oct 06, 2020 at 02:40:20PM +0800, Junchang Wang wrote:
> >> On Mon, Oct 05, 2020 at 03:12:22PM -0700, Paul E. McKenney wrote:
> >> >On Sat, Oct 03, 2020 at 09:19:25AM -0700, Paul E. McKenney wrote:
> >> >> On Sat, Oct 03, 2020 at 12:28:47PM +0800, Junchang Wang wrote:
> >> >
> >> >[ . . . ]
> >> >
> >> >> But sadly, this change does not fix this bug:
> >> >>
> >> >> $ ./hash_bkt_hazptr --schroedinger --nreaders 1 --duration 1000 --updatewait 0 --nbuckets 8192 --elems/writer 8192
> >> >> Segmentation fault (core dumped)
> >> >>
> >> >> Can't have everything. ;-)
> >> >>
> >> >> It appears that hashtorture manages to fail to call the per-thread
> >> >> hazard-pointers initialization on some paths, so it is no surprise
> >> >> that Junchang's fix doesn't fix this bug.
> >> >
> >> > Thanx, Paul
> >> >
> >> >------------------------------------------------------------------------
> >> >
> >> >commit 2533decebb7fca65d2860174246966f5ed255dd0
> >> >Author: Paul E. McKenney <paulmck@xxxxxxxxxx>
> >> >Date: Mon Oct 5 15:10:03 2020 -0700
> >> >
> >> > datastruct/hash: Add missing hash_register_thread()
> >> >
> >> > The zoo_test() function was missing the hash_register_thread() invocation
> >> > that is required to make hazard pointers work correctly. The lack
> >> > of this invocation results in a segmentation violation. This commit
> >> > therefore adds this call.
> >> >
> >> > Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
> >> >
> >>
> >> Hi Paul,
> >>
> >> This patch fixes the bug, and now "./hash_bkt_hazptr --schroedinger" works
> >> correctly on my servers. Thanks a lot.
> >
> >Thank you for testing! May I apply your Tested-by?
>
> Hi Paul,
>
> I'm very happy that I can help improve perfbook. Please add a
>
> Tested-by: Junchang Wang <junchang2020@xxxxxxxxx>
Applied, thank you!
Thanx, Paul
> Thanks,
> --Junchang
>
>
> > Thanx, Paul
> >
> >> --Junchang
> >>
> >> >diff --git a/CodeSamples/datastruct/hash/hashtorture.h b/CodeSamples/datastruct/hash/hashtorture.h
> >> >index 6d30cb8..7d43e11 100644
> >> >--- a/CodeSamples/datastruct/hash/hashtorture.h
> >> >+++ b/CodeSamples/datastruct/hash/hashtorture.h
> >> >@@ -1211,6 +1211,7 @@ void zoo_test(void)
> >> > for (i = 0; i < nupdaters * elperupdater; i++) {
> >> > sprintf(&zoo_names[ZOO_NAMELEN * i], "a%ld", i);
> >> > }
> >> >+ hash_register_thread();
> >> >
> >> > zhep = malloc(sizeof(*zhep));
> >> > BUG_ON(!zhep);
