* [dpdk-stable] [PATCH] lib/rcu: fix possible spurious thread unregister
@ 2019-09-09 13:51 Ruifeng Wang
2019-09-13 4:17 ` Honnappa Nagarahalli
2019-09-25 8:01 ` [dpdk-stable] [dpdk-dev] " David Marchand
0 siblings, 2 replies; 4+ messages in thread
From: Ruifeng Wang @ 2019-09-09 13:51 UTC (permalink / raw)
To: honnappa.nagarahalli; +Cc: dev, gavin.hu, nd, Ruifeng Wang, stable
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.
*/
--
2.17.1
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [dpdk-stable] [PATCH] lib/rcu: fix possible spurious thread unregister
2019-09-09 13:51 [dpdk-stable] [PATCH] lib/rcu: fix possible spurious thread unregister Ruifeng Wang
@ 2019-09-13 4:17 ` Honnappa Nagarahalli
2019-09-25 8:01 ` [dpdk-stable] [dpdk-dev] " David Marchand
1 sibling, 0 replies; 4+ messages in thread
From: Honnappa Nagarahalli @ 2019-09-13 4:17 UTC (permalink / raw)
To: Ruifeng Wang (Arm Technology China)
Cc: dev, Gavin Hu (Arm Technology China),
nd, Ruifeng Wang (Arm Technology China),
stable, nd
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
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [dpdk-stable] [dpdk-dev] [PATCH] lib/rcu: fix possible spurious thread unregister
2019-09-09 13:51 [dpdk-stable] [PATCH] lib/rcu: fix possible spurious thread unregister Ruifeng Wang
2019-09-13 4:17 ` Honnappa Nagarahalli
@ 2019-09-25 8:01 ` David Marchand
2019-10-18 4:11 ` David Marchand
1 sibling, 1 reply; 4+ messages in thread
From: David Marchand @ 2019-09-25 8:01 UTC (permalink / raw)
To: Ruifeng Wang, Honnappa Nagarahalli; +Cc: dev, Gavin Hu, nd, dpdk stable
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
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [dpdk-stable] [dpdk-dev] [PATCH] lib/rcu: fix possible spurious thread unregister
2019-09-25 8:01 ` [dpdk-stable] [dpdk-dev] " David Marchand
@ 2019-10-18 4:11 ` David Marchand
0 siblings, 0 replies; 4+ messages in thread
From: David Marchand @ 2019-10-18 4:11 UTC (permalink / raw)
To: Ruifeng Wang, Honnappa Nagarahalli; +Cc: dev, Gavin Hu, nd, dpdk stable
On Wed, Sep 25, 2019 at 10:01 AM David Marchand
<david.marchand@redhat.com> wrote:
>
> 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>
> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Reviewed-by: David Marchand <david.marchand@redhat.com>
Applied, thanks.
--
David Marchand
^ permalink raw reply [flat|nested] 4+ messages in thread
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2019-09-09 13:51 [dpdk-stable] [PATCH] lib/rcu: fix possible spurious thread unregister Ruifeng Wang
2019-09-13 4:17 ` Honnappa Nagarahalli
2019-09-25 8:01 ` [dpdk-stable] [dpdk-dev] " David Marchand
2019-10-18 4:11 ` David Marchand
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