From: David Marchand <david.marchand@redhat.com>
To: Ruifeng Wang <ruifeng.wang@arm.com>,
Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Cc: dev <dev@dpdk.org>, Gavin Hu <gavin.hu@arm.com>, nd <nd@arm.com>,
dpdk stable <stable@dpdk.org>
Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH] lib/rcu: fix possible spurious thread unregister
Date: Wed, 25 Sep 2019 10:01:02 +0200 [thread overview]
Message-ID: <CAJFAV8wodhC6LkKYzfvXu3GtF83hcp=Bw45KYqBnFnDp-=m9Hg@mail.gmail.com> (raw)
In-Reply-To: <20190909135142.3510-1-ruifeng.wang@arm.com>
On Mon, Sep 9, 2019 at 3:52 PM Ruifeng Wang <ruifeng.wang@arm.com> wrote:
>
> Thread unregister returns success while unregister not been performed.
> This is due to incorrect thread registration status check.
> Fix this issue by correcting bitmap check.
>
> Fixes: 64994b56cfd7 ("rcu: add RCU library supporting QSBR mechanism")
> Cc: stable@dpdk.org
>
> Signed-off-by: Ruifeng Wang <ruifeng.wang@arm.com>
> Reviewed-by: Gavin Hu <gavin.hu@arm.com>
> ---
> lib/librte_rcu/rte_rcu_qsbr.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/lib/librte_rcu/rte_rcu_qsbr.c b/lib/librte_rcu/rte_rcu_qsbr.c
> index ce7f93dd3..8c37c88cd 100644
> --- a/lib/librte_rcu/rte_rcu_qsbr.c
> +++ b/lib/librte_rcu/rte_rcu_qsbr.c
> @@ -158,7 +158,7 @@ rte_rcu_qsbr_thread_unregister(struct rte_rcu_qsbr *v, unsigned int thread_id)
> /* Check if the thread is already unregistered */
> old_bmap = __atomic_load_n(__RTE_QSBR_THRID_ARRAY_ELM(v, i),
> __ATOMIC_RELAXED);
> - if (old_bmap & ~(1UL << id))
> + if (!(old_bmap & (1UL << id)))
> return 0;
>
> do {
> @@ -175,7 +175,7 @@ rte_rcu_qsbr_thread_unregister(struct rte_rcu_qsbr *v, unsigned int thread_id)
> if (success)
> __atomic_fetch_sub(&v->num_threads,
> 1, __ATOMIC_RELAXED);
> - else if (old_bmap & ~(1UL << id))
> + else if (!(old_bmap & (1UL << id)))
> /* Someone else unregistered this thread.
> * Counter should not be incremented.
> */
Reviewed-by: David Marchand <david.marchand@redhat.com>
Honnappa,
While looking at the rcu doxygen, I noted it does not describe what
return values to expect from register/unregister.
We also have typos on s/rte_rcu_thread_offline/rte_rcu_qsbr_thread_offline/g.
Could you send a patch for this?
Thanks.
--
David Marchand
next prev parent reply other threads:[~2019-09-25 8:01 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-09 13:51 [dpdk-stable] " Ruifeng Wang
2019-09-13 4:17 ` Honnappa Nagarahalli
2019-09-25 8:01 ` David Marchand [this message]
2019-10-18 4:11 ` [dpdk-stable] [dpdk-dev] " David Marchand
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAJFAV8wodhC6LkKYzfvXu3GtF83hcp=Bw45KYqBnFnDp-=m9Hg@mail.gmail.com' \
--to=david.marchand@redhat.com \
--cc=dev@dpdk.org \
--cc=gavin.hu@arm.com \
--cc=honnappa.nagarahalli@arm.com \
--cc=nd@arm.com \
--cc=ruifeng.wang@arm.com \
--cc=stable@dpdk.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).