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>
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);
