patches for DPDK stable branches
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From: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
To: "Ruifeng Wang (Arm Technology China)" <Ruifeng.Wang@arm.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
	"Gavin Hu (Arm Technology China)" <Gavin.Hu@arm.com>,
	nd <nd@arm.com>,
	"Ruifeng Wang (Arm Technology China)" <Ruifeng.Wang@arm.com>,
	"stable@dpdk.org" <stable@dpdk.org>, nd <nd@arm.com>
Subject: Re: [dpdk-stable] [PATCH] lib/rcu: fix possible spurious thread unregister
Date: Fri, 13 Sep 2019 04:17:19 +0000
Message-ID: <AM6PR08MB51443F0FA5C3351C5193133498B30@AM6PR08MB5144.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <20190909135142.3510-1-ruifeng.wang@arm.com>

Thanks Ruifeng, looks good.

> -----Original Message-----
> From: Ruifeng Wang <ruifeng.wang@arm.com>
> Sent: Monday, September 9, 2019 8:52 AM
> To: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
> Cc: dev@dpdk.org; Gavin Hu (Arm Technology China) <Gavin.Hu@arm.com>;
> nd <nd@arm.com>; Ruifeng Wang (Arm Technology China)
> <Ruifeng.Wang@arm.com>; stable@dpdk.org
> Subject: [PATCH] lib/rcu: fix possible spurious thread unregister
> 
> 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: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>

> 2.17.1


      reply index

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-09 13:51 Ruifeng Wang
2019-09-13  4:17 ` Honnappa Nagarahalli [this message]

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