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* [dpdk-stable] [PATCH 1/3] eventdev: fix race condition on timer list counter
@ 2020-06-12 11:19 Phil Yang
  2020-06-18 15:17 ` Carrillo, Erik G
  2020-07-02  5:26 ` [dpdk-stable] [PATCH v2 1/4] " Phil Yang
  0 siblings, 2 replies; 19+ messages in thread
From: Phil Yang @ 2020-06-12 11:19 UTC (permalink / raw)
  To: dev, erik.g.carrillo
  Cc: drc, honnappa.nagarahalli, ruifeng.wang, dharmik.thakkar, nd, stable

The n_poll_lcores counter and poll_lcore array are shared between lcores
and the update of these variables are out of the protection of spinlock
on each lcore timer list. The read-modify-write operations of the counter
are not atomic, so it has the potential of race condition between lcores.

Use c11 atomics with RELAXED ordering to prevent confliction.

Fixes: cc7b73ea9e3b ("eventdev: add new software timer adapter")
Cc: erik.g.carrillo@intel.com
Cc: stable@dpdk.org

Signed-off-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
---
 lib/librte_eventdev/rte_event_timer_adapter.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/lib/librte_eventdev/rte_event_timer_adapter.c b/lib/librte_eventdev/rte_event_timer_adapter.c
index 005459f..6a0e283 100644
--- a/lib/librte_eventdev/rte_event_timer_adapter.c
+++ b/lib/librte_eventdev/rte_event_timer_adapter.c
@@ -583,6 +583,7 @@ swtim_callback(struct rte_timer *tim)
 	uint16_t nb_evs_invalid = 0;
 	uint64_t opaque;
 	int ret;
+	int n_lcores;
 
 	opaque = evtim->impl_opaque[1];
 	adapter = (struct rte_event_timer_adapter *)(uintptr_t)opaque;
@@ -605,8 +606,12 @@ swtim_callback(struct rte_timer *tim)
 				      "with immediate expiry value");
 		}
 
-		if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore].v)))
-			sw->poll_lcores[sw->n_poll_lcores++] = lcore;
+		if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore].v))) {
+			n_lcores = __atomic_fetch_add(&sw->n_poll_lcores, 1,
+						__ATOMIC_RELAXED);
+			__atomic_store_n(&sw->poll_lcores[n_lcores], lcore,
+						__ATOMIC_RELAXED);
+		}
 	} else {
 		EVTIM_BUF_LOG_DBG("buffered an event timer expiry event");
 
@@ -1011,6 +1016,7 @@ __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
 	uint32_t lcore_id = rte_lcore_id();
 	struct rte_timer *tim, *tims[nb_evtims];
 	uint64_t cycles;
+	int n_lcores;
 
 #ifdef RTE_LIBRTE_EVENTDEV_DEBUG
 	/* Check that the service is running. */
@@ -1033,8 +1039,10 @@ __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
 	if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore_id].v))) {
 		EVTIM_LOG_DBG("Adding lcore id = %u to list of lcores to poll",
 			      lcore_id);
-		sw->poll_lcores[sw->n_poll_lcores] = lcore_id;
-		++sw->n_poll_lcores;
+		n_lcores = __atomic_fetch_add(&sw->n_poll_lcores, 1,
+						__ATOMIC_RELAXED);
+		__atomic_store_n(&sw->poll_lcores[n_lcores], lcore_id,
+						__ATOMIC_RELAXED);
 	}
 
 	ret = rte_mempool_get_bulk(sw->tim_pool, (void **)tims,
-- 
2.7.4


^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [dpdk-stable] [PATCH 1/3] eventdev: fix race condition on timer list counter
  2020-06-12 11:19 [dpdk-stable] [PATCH 1/3] eventdev: fix race condition on timer list counter Phil Yang
@ 2020-06-18 15:17 ` Carrillo, Erik G
  2020-06-18 18:25   ` Honnappa Nagarahalli
  2020-06-22  9:09   ` Phil Yang
  2020-07-02  5:26 ` [dpdk-stable] [PATCH v2 1/4] " Phil Yang
  1 sibling, 2 replies; 19+ messages in thread
From: Carrillo, Erik G @ 2020-06-18 15:17 UTC (permalink / raw)
  To: Phil Yang, dev
  Cc: drc, honnappa.nagarahalli, ruifeng.wang, dharmik.thakkar, nd, stable

Hi Phil,

Good catch - thanks for the fix.   I've commented in-line:

> -----Original Message-----
> From: Phil Yang <phil.yang@arm.com>
> Sent: Friday, June 12, 2020 6:20 AM
> To: dev@dpdk.org; Carrillo, Erik G <erik.g.carrillo@intel.com>
> Cc: drc@linux.vnet.ibm.com; honnappa.nagarahalli@arm.com;
> ruifeng.wang@arm.com; dharmik.thakkar@arm.com; nd@arm.com;
> stable@dpdk.org
> Subject: [PATCH 1/3] eventdev: fix race condition on timer list counter
> 
> The n_poll_lcores counter and poll_lcore array are shared between lcores
> and the update of these variables are out of the protection of spinlock on
> each lcore timer list. The read-modify-write operations of the counter are
> not atomic, so it has the potential of race condition between lcores.
> 
> Use c11 atomics with RELAXED ordering to prevent confliction.
> 
> Fixes: cc7b73ea9e3b ("eventdev: add new software timer adapter")
> Cc: erik.g.carrillo@intel.com
> Cc: stable@dpdk.org
> 
> Signed-off-by: Phil Yang <phil.yang@arm.com>
> Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> ---
>  lib/librte_eventdev/rte_event_timer_adapter.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/lib/librte_eventdev/rte_event_timer_adapter.c
> b/lib/librte_eventdev/rte_event_timer_adapter.c
> index 005459f..6a0e283 100644
> --- a/lib/librte_eventdev/rte_event_timer_adapter.c
> +++ b/lib/librte_eventdev/rte_event_timer_adapter.c
> @@ -583,6 +583,7 @@ swtim_callback(struct rte_timer *tim)
>  	uint16_t nb_evs_invalid = 0;
>  	uint64_t opaque;
>  	int ret;
> +	int n_lcores;
> 
>  	opaque = evtim->impl_opaque[1];
>  	adapter = (struct rte_event_timer_adapter *)(uintptr_t)opaque;
> @@ -605,8 +606,12 @@ swtim_callback(struct rte_timer *tim)
>  				      "with immediate expiry value");
>  		}
> 
> -		if (unlikely(rte_atomic16_test_and_set(&sw-
> >in_use[lcore].v)))
> -			sw->poll_lcores[sw->n_poll_lcores++] = lcore;
> +		if (unlikely(rte_atomic16_test_and_set(&sw-
> >in_use[lcore].v))) {
> +			n_lcores = __atomic_fetch_add(&sw->n_poll_lcores,
> 1,
> +						__ATOMIC_RELAXED);

Just a nit, but let's align the continued line with the opening parentheses in
this location and below.  With these changes:

Acked-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com>

> +			__atomic_store_n(&sw->poll_lcores[n_lcores],
> lcore,
> +						__ATOMIC_RELAXED);
> +		}
>  	} else {
>  		EVTIM_BUF_LOG_DBG("buffered an event timer expiry
> event");
> 
> @@ -1011,6 +1016,7 @@ __swtim_arm_burst(const struct
> rte_event_timer_adapter *adapter,
>  	uint32_t lcore_id = rte_lcore_id();
>  	struct rte_timer *tim, *tims[nb_evtims];
>  	uint64_t cycles;
> +	int n_lcores;
> 
>  #ifdef RTE_LIBRTE_EVENTDEV_DEBUG
>  	/* Check that the service is running. */ @@ -1033,8 +1039,10 @@
> __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
>  	if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore_id].v))) {
>  		EVTIM_LOG_DBG("Adding lcore id = %u to list of lcores to
> poll",
>  			      lcore_id);
> -		sw->poll_lcores[sw->n_poll_lcores] = lcore_id;
> -		++sw->n_poll_lcores;
> +		n_lcores = __atomic_fetch_add(&sw->n_poll_lcores, 1,
> +						__ATOMIC_RELAXED);
> +		__atomic_store_n(&sw->poll_lcores[n_lcores], lcore_id,
> +						__ATOMIC_RELAXED);
>  	}
> 
>  	ret = rte_mempool_get_bulk(sw->tim_pool, (void **)tims,
> --
> 2.7.4


^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [dpdk-stable] [PATCH 1/3] eventdev: fix race condition on timer list counter
  2020-06-18 15:17 ` Carrillo, Erik G
@ 2020-06-18 18:25   ` Honnappa Nagarahalli
  2020-06-22  9:48     ` Phil Yang
  2020-07-02  3:26     ` [dpdk-stable] " Phil Yang
  2020-06-22  9:09   ` Phil Yang
  1 sibling, 2 replies; 19+ messages in thread
From: Honnappa Nagarahalli @ 2020-06-18 18:25 UTC (permalink / raw)
  To: Carrillo, Erik G, Phil Yang, dev
  Cc: drc, Ruifeng Wang, Dharmik Thakkar, nd, stable, Honnappa Nagarahalli, nd

<snip>

> 
> Hi Phil,
> 
> Good catch - thanks for the fix.   I've commented in-line:
> 
> > -----Original Message-----
> > From: Phil Yang <phil.yang@arm.com>
> > Sent: Friday, June 12, 2020 6:20 AM
> > To: dev@dpdk.org; Carrillo, Erik G <erik.g.carrillo@intel.com>
> > Cc: drc@linux.vnet.ibm.com; honnappa.nagarahalli@arm.com;
> > ruifeng.wang@arm.com; dharmik.thakkar@arm.com; nd@arm.com;
> > stable@dpdk.org
> > Subject: [PATCH 1/3] eventdev: fix race condition on timer list
> > counter
> >
> > The n_poll_lcores counter and poll_lcore array are shared between
> > lcores and the update of these variables are out of the protection of
> > spinlock on each lcore timer list. The read-modify-write operations of
> > the counter are not atomic, so it has the potential of race condition
> between lcores.
> >
> > Use c11 atomics with RELAXED ordering to prevent confliction.
> >
> > Fixes: cc7b73ea9e3b ("eventdev: add new software timer adapter")
> > Cc: erik.g.carrillo@intel.com
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Phil Yang <phil.yang@arm.com>
> > Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
> > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > ---
> >  lib/librte_eventdev/rte_event_timer_adapter.c | 16 ++++++++++++----
> >  1 file changed, 12 insertions(+), 4 deletions(-)
> >
> > diff --git a/lib/librte_eventdev/rte_event_timer_adapter.c
> > b/lib/librte_eventdev/rte_event_timer_adapter.c
> > index 005459f..6a0e283 100644
> > --- a/lib/librte_eventdev/rte_event_timer_adapter.c
> > +++ b/lib/librte_eventdev/rte_event_timer_adapter.c
> > @@ -583,6 +583,7 @@ swtim_callback(struct rte_timer *tim)
> >  	uint16_t nb_evs_invalid = 0;
> >  	uint64_t opaque;
> >  	int ret;
> > +	int n_lcores;
> >
> >  	opaque = evtim->impl_opaque[1];
> >  	adapter = (struct rte_event_timer_adapter *)(uintptr_t)opaque; @@
> > -605,8 +606,12 @@ swtim_callback(struct rte_timer *tim)
> >  				      "with immediate expiry value");
> >  		}
> >
> > -		if (unlikely(rte_atomic16_test_and_set(&sw-
> > >in_use[lcore].v)))
> > -			sw->poll_lcores[sw->n_poll_lcores++] = lcore;
> > +		if (unlikely(rte_atomic16_test_and_set(&sw-
> > >in_use[lcore].v))) {
> > +			n_lcores = __atomic_fetch_add(&sw->n_poll_lcores,
> > 1,
> > +						__ATOMIC_RELAXED);
Since this commit will be back ported, we should prefer to use rte_atomic APIs for this commit. Otherwise, we will have a mix of rte_atomic and C11 APIs.
My suggestion is to fix this bug using rte_atomic so that backported code will have only rte_atomic APIs. Add another commit (if required) in this series to make the bug fix use C11 APIs (this commit will not be backported).

> 
> Just a nit, but let's align the continued line with the opening parentheses in
> this location and below.  With these changes:
> 
> Acked-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com>
> 
> > +			__atomic_store_n(&sw->poll_lcores[n_lcores],
> > lcore,
> > +						__ATOMIC_RELAXED);
> > +		}
> >  	} else {
> >  		EVTIM_BUF_LOG_DBG("buffered an event timer expiry event");
> >
> > @@ -1011,6 +1016,7 @@ __swtim_arm_burst(const struct
> > rte_event_timer_adapter *adapter,
> >  	uint32_t lcore_id = rte_lcore_id();
> >  	struct rte_timer *tim, *tims[nb_evtims];
> >  	uint64_t cycles;
> > +	int n_lcores;
> >
> >  #ifdef RTE_LIBRTE_EVENTDEV_DEBUG
> >  	/* Check that the service is running. */ @@ -1033,8 +1039,10 @@
> > __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
> >  	if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore_id].v))) {
> >  		EVTIM_LOG_DBG("Adding lcore id = %u to list of lcores to
> poll",
> >  			      lcore_id);
> > -		sw->poll_lcores[sw->n_poll_lcores] = lcore_id;
> > -		++sw->n_poll_lcores;
> > +		n_lcores = __atomic_fetch_add(&sw->n_poll_lcores, 1,
> > +						__ATOMIC_RELAXED);
> > +		__atomic_store_n(&sw->poll_lcores[n_lcores], lcore_id,
> > +						__ATOMIC_RELAXED);
> >  	}
> >
> >  	ret = rte_mempool_get_bulk(sw->tim_pool, (void **)tims,
> > --
> > 2.7.4


^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [dpdk-stable] [PATCH 1/3] eventdev: fix race condition on timer list counter
  2020-06-18 15:17 ` Carrillo, Erik G
  2020-06-18 18:25   ` Honnappa Nagarahalli
@ 2020-06-22  9:09   ` Phil Yang
  1 sibling, 0 replies; 19+ messages in thread
From: Phil Yang @ 2020-06-22  9:09 UTC (permalink / raw)
  To: Carrillo, Erik G, dev
  Cc: drc, Honnappa Nagarahalli, Ruifeng Wang, Dharmik Thakkar, nd, stable

> -----Original Message-----
> From: Carrillo, Erik G <erik.g.carrillo@intel.com>
> Sent: Thursday, June 18, 2020 11:18 PM
> To: Phil Yang <Phil.Yang@arm.com>; dev@dpdk.org
> Cc: drc@linux.vnet.ibm.com; Honnappa Nagarahalli
> <Honnappa.Nagarahalli@arm.com>; Ruifeng Wang
> <Ruifeng.Wang@arm.com>; Dharmik Thakkar <Dharmik.Thakkar@arm.com>;
> nd <nd@arm.com>; stable@dpdk.org
> Subject: RE: [PATCH 1/3] eventdev: fix race condition on timer list counter
> 
> Hi Phil,
> 
> Good catch - thanks for the fix.   I've commented in-line:
> 
> > -----Original Message-----
> > From: Phil Yang <phil.yang@arm.com>
> > Sent: Friday, June 12, 2020 6:20 AM
> > To: dev@dpdk.org; Carrillo, Erik G <erik.g.carrillo@intel.com>
> > Cc: drc@linux.vnet.ibm.com; honnappa.nagarahalli@arm.com;
> > ruifeng.wang@arm.com; dharmik.thakkar@arm.com; nd@arm.com;
> > stable@dpdk.org
> > Subject: [PATCH 1/3] eventdev: fix race condition on timer list counter
> >
> > The n_poll_lcores counter and poll_lcore array are shared between lcores
> > and the update of these variables are out of the protection of spinlock on
> > each lcore timer list. The read-modify-write operations of the counter are
> > not atomic, so it has the potential of race condition between lcores.
> >
> > Use c11 atomics with RELAXED ordering to prevent confliction.
> >
> > Fixes: cc7b73ea9e3b ("eventdev: add new software timer adapter")
> > Cc: erik.g.carrillo@intel.com
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Phil Yang <phil.yang@arm.com>
> > Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
> > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > ---
> >  lib/librte_eventdev/rte_event_timer_adapter.c | 16 ++++++++++++----
> >  1 file changed, 12 insertions(+), 4 deletions(-)
> >
> > diff --git a/lib/librte_eventdev/rte_event_timer_adapter.c
> > b/lib/librte_eventdev/rte_event_timer_adapter.c
> > index 005459f..6a0e283 100644
> > --- a/lib/librte_eventdev/rte_event_timer_adapter.c
> > +++ b/lib/librte_eventdev/rte_event_timer_adapter.c
> > @@ -583,6 +583,7 @@ swtim_callback(struct rte_timer *tim)
> >  	uint16_t nb_evs_invalid = 0;
> >  	uint64_t opaque;
> >  	int ret;
> > +	int n_lcores;
> >
> >  	opaque = evtim->impl_opaque[1];
> >  	adapter = (struct rte_event_timer_adapter *)(uintptr_t)opaque;
> > @@ -605,8 +606,12 @@ swtim_callback(struct rte_timer *tim)
> >  				      "with immediate expiry value");
> >  		}
> >
> > -		if (unlikely(rte_atomic16_test_and_set(&sw-
> > >in_use[lcore].v)))
> > -			sw->poll_lcores[sw->n_poll_lcores++] = lcore;
> > +		if (unlikely(rte_atomic16_test_and_set(&sw-
> > >in_use[lcore].v))) {
> > +			n_lcores = __atomic_fetch_add(&sw->n_poll_lcores,
> > 1,
> > +						__ATOMIC_RELAXED);
> 
> Just a nit, but let's align the continued line with the opening parentheses in
> this location and below.  With these changes:

Thanks Erik. 
I will do it in the new version.

> 
> Acked-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com>
> 
> > +			__atomic_store_n(&sw->poll_lcores[n_lcores],
> > lcore,
> > +						__ATOMIC_RELAXED);
> > +		}
> >  	} else {
> >  		EVTIM_BUF_LOG_DBG("buffered an event timer expiry
> > event");
> >
> > @@ -1011,6 +1016,7 @@ __swtim_arm_burst(const struct
> > rte_event_timer_adapter *adapter,
> >  	uint32_t lcore_id = rte_lcore_id();
> >  	struct rte_timer *tim, *tims[nb_evtims];
> >  	uint64_t cycles;
> > +	int n_lcores;
> >
> >  #ifdef RTE_LIBRTE_EVENTDEV_DEBUG
> >  	/* Check that the service is running. */ @@ -1033,8 +1039,10 @@
> > __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
> >  	if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore_id].v))) {
> >  		EVTIM_LOG_DBG("Adding lcore id = %u to list of lcores to
> > poll",
> >  			      lcore_id);
> > -		sw->poll_lcores[sw->n_poll_lcores] = lcore_id;
> > -		++sw->n_poll_lcores;
> > +		n_lcores = __atomic_fetch_add(&sw->n_poll_lcores, 1,
> > +						__ATOMIC_RELAXED);
> > +		__atomic_store_n(&sw->poll_lcores[n_lcores], lcore_id,
> > +						__ATOMIC_RELAXED);
> >  	}
> >
> >  	ret = rte_mempool_get_bulk(sw->tim_pool, (void **)tims,
> > --
> > 2.7.4


^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [dpdk-stable] [PATCH 1/3] eventdev: fix race condition on timer list counter
  2020-06-18 18:25   ` Honnappa Nagarahalli
@ 2020-06-22  9:48     ` Phil Yang
  2020-07-01 11:22       ` [dpdk-stable] [dpdk-dev] " Jerin Jacob
  2020-07-02  3:26     ` [dpdk-stable] " Phil Yang
  1 sibling, 1 reply; 19+ messages in thread
From: Phil Yang @ 2020-06-22  9:48 UTC (permalink / raw)
  To: Honnappa Nagarahalli, Carrillo, Erik G, dev
  Cc: drc, Ruifeng Wang, Dharmik Thakkar, nd, stable, nd

> -----Original Message-----
> From: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
> Sent: Friday, June 19, 2020 2:26 AM
> To: Carrillo, Erik G <erik.g.carrillo@intel.com>; Phil Yang
> <Phil.Yang@arm.com>; dev@dpdk.org
> Cc: drc@linux.vnet.ibm.com; Ruifeng Wang <Ruifeng.Wang@arm.com>;
> Dharmik Thakkar <Dharmik.Thakkar@arm.com>; nd <nd@arm.com>;
> stable@dpdk.org; Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>;
> nd <nd@arm.com>
> Subject: RE: [PATCH 1/3] eventdev: fix race condition on timer list counter
> 
> <snip>
> 
> >
> > Hi Phil,
> >
> > Good catch - thanks for the fix.   I've commented in-line:
> >
> > > -----Original Message-----
> > > From: Phil Yang <phil.yang@arm.com>
> > > Sent: Friday, June 12, 2020 6:20 AM
> > > To: dev@dpdk.org; Carrillo, Erik G <erik.g.carrillo@intel.com>
> > > Cc: drc@linux.vnet.ibm.com; honnappa.nagarahalli@arm.com;
> > > ruifeng.wang@arm.com; dharmik.thakkar@arm.com; nd@arm.com;
> > > stable@dpdk.org
> > > Subject: [PATCH 1/3] eventdev: fix race condition on timer list
> > > counter
> > >
> > > The n_poll_lcores counter and poll_lcore array are shared between
> > > lcores and the update of these variables are out of the protection of
> > > spinlock on each lcore timer list. The read-modify-write operations of
> > > the counter are not atomic, so it has the potential of race condition
> > between lcores.
> > >
> > > Use c11 atomics with RELAXED ordering to prevent confliction.
> > >
> > > Fixes: cc7b73ea9e3b ("eventdev: add new software timer adapter")
> > > Cc: erik.g.carrillo@intel.com
> > > Cc: stable@dpdk.org
> > >
> > > Signed-off-by: Phil Yang <phil.yang@arm.com>
> > > Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
> > > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > > ---
> > >  lib/librte_eventdev/rte_event_timer_adapter.c | 16 ++++++++++++----
> > >  1 file changed, 12 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/lib/librte_eventdev/rte_event_timer_adapter.c
> > > b/lib/librte_eventdev/rte_event_timer_adapter.c
> > > index 005459f..6a0e283 100644
> > > --- a/lib/librte_eventdev/rte_event_timer_adapter.c
> > > +++ b/lib/librte_eventdev/rte_event_timer_adapter.c
> > > @@ -583,6 +583,7 @@ swtim_callback(struct rte_timer *tim)
> > >  uint16_t nb_evs_invalid = 0;
> > >  uint64_t opaque;
> > >  int ret;
> > > +int n_lcores;
> > >
> > >  opaque = evtim->impl_opaque[1];
> > >  adapter = (struct rte_event_timer_adapter *)(uintptr_t)opaque; @@
> > > -605,8 +606,12 @@ swtim_callback(struct rte_timer *tim)
> > >        "with immediate expiry value");
> > >  }
> > >
> > > -if (unlikely(rte_atomic16_test_and_set(&sw-
> > > >in_use[lcore].v)))
> > > -sw->poll_lcores[sw->n_poll_lcores++] = lcore;
> > > +if (unlikely(rte_atomic16_test_and_set(&sw-
> > > >in_use[lcore].v))) {
> > > +n_lcores = __atomic_fetch_add(&sw->n_poll_lcores,
> > > 1,
> > > +__ATOMIC_RELAXED);
> Since this commit will be back ported, we should prefer to use rte_atomic
> APIs for this commit. Otherwise, we will have a mix of rte_atomic and C11
> APIs.
> My suggestion is to fix this bug using rte_atomic so that backported code will
> have only rte_atomic APIs. Add another commit (if required) in this series to
> make the bug fix use C11 APIs (this commit will not be backported).

Agree. 
I will change this patch to the rte_atomic version in the next version.

Thanks,
Phil

> 
> >
> > Just a nit, but let's align the continued line with the opening parentheses in
> > this location and below.  With these changes:
> >
> > Acked-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com>
> >
> > > +__atomic_store_n(&sw->poll_lcores[n_lcores],
> > > lcore,
> > > +__ATOMIC_RELAXED);
> > > +}
> > >  } else {
> > >  EVTIM_BUF_LOG_DBG("buffered an event timer expiry event");
> > >
> > > @@ -1011,6 +1016,7 @@ __swtim_arm_burst(const struct
> > > rte_event_timer_adapter *adapter,
> > >  uint32_t lcore_id = rte_lcore_id();
> > >  struct rte_timer *tim, *tims[nb_evtims];
> > >  uint64_t cycles;
> > > +int n_lcores;
> > >
> > >  #ifdef RTE_LIBRTE_EVENTDEV_DEBUG
> > >  /* Check that the service is running. */ @@ -1033,8 +1039,10 @@
> > > __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
> > >  if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore_id].v))) {
> > >  EVTIM_LOG_DBG("Adding lcore id = %u to list of lcores to
> > poll",
> > >        lcore_id);
> > > -sw->poll_lcores[sw->n_poll_lcores] = lcore_id;
> > > -++sw->n_poll_lcores;
> > > +n_lcores = __atomic_fetch_add(&sw->n_poll_lcores, 1,
> > > +__ATOMIC_RELAXED);
> > > +__atomic_store_n(&sw->poll_lcores[n_lcores], lcore_id,
> > > +__ATOMIC_RELAXED);
> > >  }
> > >
> > >  ret = rte_mempool_get_bulk(sw->tim_pool, (void **)tims,
> > > --
> > > 2.7.4
> 


^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [dpdk-stable] [dpdk-dev] [PATCH 1/3] eventdev: fix race condition on timer list counter
  2020-06-22  9:48     ` Phil Yang
@ 2020-07-01 11:22       ` " Jerin Jacob
  2020-07-02  3:28         ` Phil Yang
  0 siblings, 1 reply; 19+ messages in thread
From: Jerin Jacob @ 2020-07-01 11:22 UTC (permalink / raw)
  To: Phil Yang
  Cc: Honnappa Nagarahalli, Carrillo, Erik G, dev, drc, Ruifeng Wang,
	Dharmik Thakkar, nd, stable

On Mon, Jun 22, 2020 at 3:18 PM Phil Yang <Phil.Yang@arm.com> wrote:
>
> > -----Original Message-----
> > From: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
> > Sent: Friday, June 19, 2020 2:26 AM
> > To: Carrillo, Erik G <erik.g.carrillo@intel.com>; Phil Yang
> > <Phil.Yang@arm.com>; dev@dpdk.org
> > Cc: drc@linux.vnet.ibm.com; Ruifeng Wang <Ruifeng.Wang@arm.com>;
> > Dharmik Thakkar <Dharmik.Thakkar@arm.com>; nd <nd@arm.com>;
> > stable@dpdk.org; Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>;
> > nd <nd@arm.com>
> > Subject: RE: [PATCH 1/3] eventdev: fix race condition on timer list counter
> >

> > Since this commit will be back ported, we should prefer to use rte_atomic
> > APIs for this commit. Otherwise, we will have a mix of rte_atomic and C11
> > APIs.
> > My suggestion is to fix this bug using rte_atomic so that backported code will
> > have only rte_atomic APIs. Add another commit (if required) in this series to
> > make the bug fix use C11 APIs (this commit will not be backported).
>
> Agree.
> I will change this patch to the rte_atomic version in the next version.

Hi Phil,

Could you send the next version? I would like to take this series for
RC1(next-eventdev tree)


>
> Thanks,
> Phil
>

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [dpdk-stable] [PATCH 1/3] eventdev: fix race condition on timer list counter
  2020-06-18 18:25   ` Honnappa Nagarahalli
  2020-06-22  9:48     ` Phil Yang
@ 2020-07-02  3:26     ` " Phil Yang
  2020-07-02  3:56       ` Honnappa Nagarahalli
  1 sibling, 1 reply; 19+ messages in thread
From: Phil Yang @ 2020-07-02  3:26 UTC (permalink / raw)
  To: Honnappa Nagarahalli, Carrillo, Erik G, dev
  Cc: drc, Ruifeng Wang, Dharmik Thakkar, nd, stable, nd, jerinj

> -----Original Message-----
> From: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
> Sent: Friday, June 19, 2020 2:26 AM
> To: Carrillo, Erik G <erik.g.carrillo@intel.com>; Phil Yang
> <Phil.Yang@arm.com>; dev@dpdk.org
> Cc: drc@linux.vnet.ibm.com; Ruifeng Wang <Ruifeng.Wang@arm.com>;
> Dharmik Thakkar <Dharmik.Thakkar@arm.com>; nd <nd@arm.com>;
> stable@dpdk.org; Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>;
> nd <nd@arm.com>
> Subject: RE: [PATCH 1/3] eventdev: fix race condition on timer list counter
> 
> <snip>
> 
> >
> > Hi Phil,
> >
> > Good catch - thanks for the fix.   I've commented in-line:
> >
> > > -----Original Message-----
> > > From: Phil Yang <phil.yang@arm.com>
> > > Sent: Friday, June 12, 2020 6:20 AM
> > > To: dev@dpdk.org; Carrillo, Erik G <erik.g.carrillo@intel.com>
> > > Cc: drc@linux.vnet.ibm.com; honnappa.nagarahalli@arm.com;
> > > ruifeng.wang@arm.com; dharmik.thakkar@arm.com; nd@arm.com;
> > > stable@dpdk.org
> > > Subject: [PATCH 1/3] eventdev: fix race condition on timer list
> > > counter
> > >
> > > The n_poll_lcores counter and poll_lcore array are shared between
> > > lcores and the update of these variables are out of the protection of
> > > spinlock on each lcore timer list. The read-modify-write operations of
> > > the counter are not atomic, so it has the potential of race condition
> > between lcores.
> > >
> > > Use c11 atomics with RELAXED ordering to prevent confliction.
> > >
> > > Fixes: cc7b73ea9e3b ("eventdev: add new software timer adapter")
> > > Cc: erik.g.carrillo@intel.com
> > > Cc: stable@dpdk.org
> > >
> > > Signed-off-by: Phil Yang <phil.yang@arm.com>
> > > Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
> > > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > > ---
> > >  lib/librte_eventdev/rte_event_timer_adapter.c | 16 ++++++++++++----
> > >  1 file changed, 12 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/lib/librte_eventdev/rte_event_timer_adapter.c
> > > b/lib/librte_eventdev/rte_event_timer_adapter.c
> > > index 005459f..6a0e283 100644
> > > --- a/lib/librte_eventdev/rte_event_timer_adapter.c
> > > +++ b/lib/librte_eventdev/rte_event_timer_adapter.c
> > > @@ -583,6 +583,7 @@ swtim_callback(struct rte_timer *tim)
> > >  uint16_t nb_evs_invalid = 0;
> > >  uint64_t opaque;
> > >  int ret;
> > > +int n_lcores;
> > >
> > >  opaque = evtim->impl_opaque[1];
> > >  adapter = (struct rte_event_timer_adapter *)(uintptr_t)opaque; @@
> > > -605,8 +606,12 @@ swtim_callback(struct rte_timer *tim)
> > >        "with immediate expiry value");
> > >  }
> > >
> > > -if (unlikely(rte_atomic16_test_and_set(&sw-
> > > >in_use[lcore].v)))
> > > -sw->poll_lcores[sw->n_poll_lcores++] = lcore;
> > > +if (unlikely(rte_atomic16_test_and_set(&sw-
> > > >in_use[lcore].v))) {
> > > +n_lcores = __atomic_fetch_add(&sw->n_poll_lcores,
> > > 1,
> > > +__ATOMIC_RELAXED);
> Since this commit will be back ported, we should prefer to use rte_atomic
> APIs for this commit. Otherwise, we will have a mix of rte_atomic and C11
> APIs.
> My suggestion is to fix this bug using rte_atomic so that backported code will
> have only rte_atomic APIs. Add another commit (if required) in this series to
> make the bug fix use C11 APIs (this commit will not be backported).

Hi Honnappa,

It doesn't have an applicable rte_atomic_XXX API to fix this issue.
The rte_atomic32_inc doesn't return the original value of the input parameter and rte_atomic32_add_return can only return the new value.

Meanwhile, the rte_timer_alt_manage & rte_timer_stop_all API not support rte_atomic type parameters. We might need to rewrite these two APIs if we want to use rte_atomic operations for n_pol_lcores and poll_lcores array.

So, a better solution could be to backport the entire c11 solution to stable releases.

Thanks,
Phil

> 
> >
> > Just a nit, but let's align the continued line with the opening parentheses in
> > this location and below.  With these changes:
> >
> > Acked-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com>
> >
> > > +__atomic_store_n(&sw->poll_lcores[n_lcores],
> > > lcore,
> > > +__ATOMIC_RELAXED);
> > > +}
> > >  } else {
> > >  EVTIM_BUF_LOG_DBG("buffered an event timer expiry event");
> > >
> > > @@ -1011,6 +1016,7 @@ __swtim_arm_burst(const struct
> > > rte_event_timer_adapter *adapter,
> > >  uint32_t lcore_id = rte_lcore_id();
> > >  struct rte_timer *tim, *tims[nb_evtims];
> > >  uint64_t cycles;
> > > +int n_lcores;
> > >
> > >  #ifdef RTE_LIBRTE_EVENTDEV_DEBUG
> > >  /* Check that the service is running. */ @@ -1033,8 +1039,10 @@
> > > __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
> > >  if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore_id].v))) {
> > >  EVTIM_LOG_DBG("Adding lcore id = %u to list of lcores to
> > poll",
> > >        lcore_id);
> > > -sw->poll_lcores[sw->n_poll_lcores] = lcore_id;
> > > -++sw->n_poll_lcores;
> > > +n_lcores = __atomic_fetch_add(&sw->n_poll_lcores, 1,
> > > +__ATOMIC_RELAXED);
> > > +__atomic_store_n(&sw->poll_lcores[n_lcores], lcore_id,
> > > +__ATOMIC_RELAXED);
> > >  }
> > >
> > >  ret = rte_mempool_get_bulk(sw->tim_pool, (void **)tims,
> > > --
> > > 2.7.4
> 


^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [dpdk-stable] [dpdk-dev] [PATCH 1/3] eventdev: fix race condition on timer list counter
  2020-07-01 11:22       ` [dpdk-stable] [dpdk-dev] " Jerin Jacob
@ 2020-07-02  3:28         ` Phil Yang
  0 siblings, 0 replies; 19+ messages in thread
From: Phil Yang @ 2020-07-02  3:28 UTC (permalink / raw)
  To: Jerin Jacob
  Cc: Honnappa Nagarahalli, Carrillo, Erik G, dev, drc, Ruifeng Wang,
	Dharmik Thakkar, nd, stable

> -----Original Message-----
> From: Jerin Jacob <jerinjacobk@gmail.com>
> Sent: Wednesday, July 1, 2020 7:22 PM
> To: Phil Yang <Phil.Yang@arm.com>
> Cc: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>; Carrillo, Erik G
> <erik.g.carrillo@intel.com>; dev@dpdk.org; drc@linux.vnet.ibm.com;
> Ruifeng Wang <Ruifeng.Wang@arm.com>; Dharmik Thakkar
> <Dharmik.Thakkar@arm.com>; nd <nd@arm.com>; stable@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH 1/3] eventdev: fix race condition on timer list
> counter
> 
> On Mon, Jun 22, 2020 at 3:18 PM Phil Yang <Phil.Yang@arm.com> wrote:
> >
> > > -----Original Message-----
> > > From: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
> > > Sent: Friday, June 19, 2020 2:26 AM
> > > To: Carrillo, Erik G <erik.g.carrillo@intel.com>; Phil Yang
> > > <Phil.Yang@arm.com>; dev@dpdk.org
> > > Cc: drc@linux.vnet.ibm.com; Ruifeng Wang <Ruifeng.Wang@arm.com>;
> > > Dharmik Thakkar <Dharmik.Thakkar@arm.com>; nd <nd@arm.com>;
> > > stable@dpdk.org; Honnappa Nagarahalli
> <Honnappa.Nagarahalli@arm.com>;
> > > nd <nd@arm.com>
> > > Subject: RE: [PATCH 1/3] eventdev: fix race condition on timer list counter
> > >
> 
> > > Since this commit will be back ported, we should prefer to use rte_atomic
> > > APIs for this commit. Otherwise, we will have a mix of rte_atomic and C11
> > > APIs.
> > > My suggestion is to fix this bug using rte_atomic so that backported code
> will
> > > have only rte_atomic APIs. Add another commit (if required) in this series
> to
> > > make the bug fix use C11 APIs (this commit will not be backported).
> >
> > Agree.
> > I will change this patch to the rte_atomic version in the next version.
> 
> Hi Phil,
> 
> Could you send the next version? I would like to take this series for
> RC1(next-eventdev tree)

Thanks, Jerin.
I will upstream the new patch series soon.


> 
> 
> >
> > Thanks,
> > Phil
> >

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [dpdk-stable] [PATCH 1/3] eventdev: fix race condition on timer list counter
  2020-07-02  3:26     ` [dpdk-stable] " Phil Yang
@ 2020-07-02  3:56       ` Honnappa Nagarahalli
  2020-07-02 21:15         ` Carrillo, Erik G
  0 siblings, 1 reply; 19+ messages in thread
From: Honnappa Nagarahalli @ 2020-07-02  3:56 UTC (permalink / raw)
  To: Phil Yang, Carrillo, Erik G, dev
  Cc: drc, Ruifeng Wang, Dharmik Thakkar, stable, nd, jerinj,
	Honnappa Nagarahalli, nd

<snip>
> >
> > >
> > > Hi Phil,
> > >
> > > Good catch - thanks for the fix.   I've commented in-line:
> > >
> > > > -----Original Message-----
> > > > From: Phil Yang <phil.yang@arm.com>
> > > > Sent: Friday, June 12, 2020 6:20 AM
> > > > To: dev@dpdk.org; Carrillo, Erik G <erik.g.carrillo@intel.com>
> > > > Cc: drc@linux.vnet.ibm.com; honnappa.nagarahalli@arm.com;
> > > > ruifeng.wang@arm.com; dharmik.thakkar@arm.com; nd@arm.com;
> > > > stable@dpdk.org
> > > > Subject: [PATCH 1/3] eventdev: fix race condition on timer list
> > > > counter
> > > >
> > > > The n_poll_lcores counter and poll_lcore array are shared between
> > > > lcores and the update of these variables are out of the protection
> > > > of spinlock on each lcore timer list. The read-modify-write
> > > > operations of the counter are not atomic, so it has the potential
> > > > of race condition
> > > between lcores.
> > > >
> > > > Use c11 atomics with RELAXED ordering to prevent confliction.
> > > >
> > > > Fixes: cc7b73ea9e3b ("eventdev: add new software timer adapter")
> > > > Cc: erik.g.carrillo@intel.com
> > > > Cc: stable@dpdk.org
> > > >
> > > > Signed-off-by: Phil Yang <phil.yang@arm.com>
> > > > Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
> > > > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > > > ---
> > > >  lib/librte_eventdev/rte_event_timer_adapter.c | 16
> > > > ++++++++++++----
> > > >  1 file changed, 12 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/lib/librte_eventdev/rte_event_timer_adapter.c
> > > > b/lib/librte_eventdev/rte_event_timer_adapter.c
> > > > index 005459f..6a0e283 100644
> > > > --- a/lib/librte_eventdev/rte_event_timer_adapter.c
> > > > +++ b/lib/librte_eventdev/rte_event_timer_adapter.c
> > > > @@ -583,6 +583,7 @@ swtim_callback(struct rte_timer *tim)
> > > > uint16_t nb_evs_invalid = 0;  uint64_t opaque;  int ret;
> > > > +int n_lcores;
> > > >
> > > >  opaque = evtim->impl_opaque[1];
> > > >  adapter = (struct rte_event_timer_adapter *)(uintptr_t)opaque; @@
> > > > -605,8 +606,12 @@ swtim_callback(struct rte_timer *tim)
> > > >        "with immediate expiry value");  }
> > > >
> > > > -if (unlikely(rte_atomic16_test_and_set(&sw-
> > > > >in_use[lcore].v)))
> > > > -sw->poll_lcores[sw->n_poll_lcores++] = lcore;
> > > > +if (unlikely(rte_atomic16_test_and_set(&sw-
> > > > >in_use[lcore].v))) {
> > > > +n_lcores = __atomic_fetch_add(&sw->n_poll_lcores,
> > > > 1,
> > > > +__ATOMIC_RELAXED);
> > Since this commit will be back ported, we should prefer to use
> > rte_atomic APIs for this commit. Otherwise, we will have a mix of
> > rte_atomic and C11 APIs.
> > My suggestion is to fix this bug using rte_atomic so that backported
> > code will have only rte_atomic APIs. Add another commit (if required)
> > in this series to make the bug fix use C11 APIs (this commit will not be
> backported).
> 
> Hi Honnappa,
> 
> It doesn't have an applicable rte_atomic_XXX API to fix this issue.
> The rte_atomic32_inc doesn't return the original value of the input parameter
> and rte_atomic32_add_return can only return the new value.
Ok, understood.

> 
> Meanwhile, the rte_timer_alt_manage & rte_timer_stop_all API not support
> rte_atomic type parameters. We might need to rewrite these two APIs if we
> want to use rte_atomic operations for n_pol_lcores and poll_lcores array.
> 
> So, a better solution could be to backport the entire c11 solution to stable
> releases.
I am ok with the approach.
Erik, are you ok with this?

> 
> Thanks,
> Phil
> 
> >
> > >
> > > Just a nit, but let's align the continued line with the opening
> > > parentheses in this location and below.  With these changes:
> > >
> > > Acked-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com>
> > >
> > > > +__atomic_store_n(&sw->poll_lcores[n_lcores],
> > > > lcore,
> > > > +__ATOMIC_RELAXED);
> > > > +}
> > > >  } else {
> > > >  EVTIM_BUF_LOG_DBG("buffered an event timer expiry event");
> > > >
> > > > @@ -1011,6 +1016,7 @@ __swtim_arm_burst(const struct
> > > > rte_event_timer_adapter *adapter,  uint32_t lcore_id =
> > > > rte_lcore_id();  struct rte_timer *tim, *tims[nb_evtims];
> > > > uint64_t cycles;
> > > > +int n_lcores;
> > > >
> > > >  #ifdef RTE_LIBRTE_EVENTDEV_DEBUG
> > > >  /* Check that the service is running. */ @@ -1033,8 +1039,10 @@
> > > > __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
> > > > if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore_id].v)))
> > > > {  EVTIM_LOG_DBG("Adding lcore id = %u to list of lcores to
> > > poll",
> > > >        lcore_id);
> > > > -sw->poll_lcores[sw->n_poll_lcores] = lcore_id;
> > > > -++sw->n_poll_lcores;
> > > > +n_lcores = __atomic_fetch_add(&sw->n_poll_lcores, 1,
> > > > +__ATOMIC_RELAXED); __atomic_store_n(&sw->poll_lcores[n_lcores],
> > > > +lcore_id, __ATOMIC_RELAXED);
> > > >  }
> > > >
> > > >  ret = rte_mempool_get_bulk(sw->tim_pool, (void **)tims,
> > > > --
> > > > 2.7.4
> >


^ permalink raw reply	[flat|nested] 19+ messages in thread

* [dpdk-stable] [PATCH v2 1/4] eventdev: fix race condition on timer list counter
  2020-06-12 11:19 [dpdk-stable] [PATCH 1/3] eventdev: fix race condition on timer list counter Phil Yang
  2020-06-18 15:17 ` Carrillo, Erik G
@ 2020-07-02  5:26 ` " Phil Yang
  2020-07-07 11:13   ` [dpdk-stable] [PATCH v3 " Phil Yang
  1 sibling, 1 reply; 19+ messages in thread
From: Phil Yang @ 2020-07-02  5:26 UTC (permalink / raw)
  To: erik.g.carrillo, dev
  Cc: jerinj, Honnappa.Nagarahalli, drc, Ruifeng.Wang, Dharmik.Thakkar,
	nd, stable

The n_poll_lcores counter and poll_lcore array are shared between lcores
and the update of these variables are out of the protection of spinlock
on each lcore timer list. The read-modify-write operations of the counter
are not atomic, so it has the potential of race condition between lcores.

Use c11 atomics with RELAXED ordering to prevent confliction.

Fixes: cc7b73ea9e3b ("eventdev: add new software timer adapter")
Cc: erik.g.carrillo@intel.com
Cc: stable@dpdk.org

Signed-off-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Acked-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com>
---
v2:
Align the code. (Erik)

 lib/librte_eventdev/rte_event_timer_adapter.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/lib/librte_eventdev/rte_event_timer_adapter.c b/lib/librte_eventdev/rte_event_timer_adapter.c
index 005459f..a36d3d2 100644
--- a/lib/librte_eventdev/rte_event_timer_adapter.c
+++ b/lib/librte_eventdev/rte_event_timer_adapter.c
@@ -583,6 +583,7 @@ swtim_callback(struct rte_timer *tim)
 	uint16_t nb_evs_invalid = 0;
 	uint64_t opaque;
 	int ret;
+	int n_lcores;
 
 	opaque = evtim->impl_opaque[1];
 	adapter = (struct rte_event_timer_adapter *)(uintptr_t)opaque;
@@ -605,8 +606,12 @@ swtim_callback(struct rte_timer *tim)
 				      "with immediate expiry value");
 		}
 
-		if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore].v)))
-			sw->poll_lcores[sw->n_poll_lcores++] = lcore;
+		if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore].v))) {
+			n_lcores = __atomic_fetch_add(&sw->n_poll_lcores, 1,
+						     __ATOMIC_RELAXED);
+			__atomic_store_n(&sw->poll_lcores[n_lcores], lcore,
+					__ATOMIC_RELAXED);
+		}
 	} else {
 		EVTIM_BUF_LOG_DBG("buffered an event timer expiry event");
 
@@ -1011,6 +1016,7 @@ __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
 	uint32_t lcore_id = rte_lcore_id();
 	struct rte_timer *tim, *tims[nb_evtims];
 	uint64_t cycles;
+	int n_lcores;
 
 #ifdef RTE_LIBRTE_EVENTDEV_DEBUG
 	/* Check that the service is running. */
@@ -1033,8 +1039,10 @@ __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
 	if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore_id].v))) {
 		EVTIM_LOG_DBG("Adding lcore id = %u to list of lcores to poll",
 			      lcore_id);
-		sw->poll_lcores[sw->n_poll_lcores] = lcore_id;
-		++sw->n_poll_lcores;
+		n_lcores = __atomic_fetch_add(&sw->n_poll_lcores, 1,
+					     __ATOMIC_RELAXED);
+		__atomic_store_n(&sw->poll_lcores[n_lcores], lcore_id,
+				__ATOMIC_RELAXED);
 	}
 
 	ret = rte_mempool_get_bulk(sw->tim_pool, (void **)tims,
-- 
2.7.4


^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [dpdk-stable] [PATCH 1/3] eventdev: fix race condition on timer list counter
  2020-07-02  3:56       ` Honnappa Nagarahalli
@ 2020-07-02 21:15         ` Carrillo, Erik G
  2020-07-02 21:30           ` Honnappa Nagarahalli
  0 siblings, 1 reply; 19+ messages in thread
From: Carrillo, Erik G @ 2020-07-02 21:15 UTC (permalink / raw)
  To: Honnappa Nagarahalli, Phil Yang, dev
  Cc: drc, Ruifeng Wang, Dharmik Thakkar, stable, nd, jerinj, nd



> -----Original Message-----
> From: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
> Sent: Wednesday, July 1, 2020 10:56 PM
> To: Phil Yang <Phil.Yang@arm.com>; Carrillo, Erik G
> <erik.g.carrillo@intel.com>; dev@dpdk.org
> Cc: drc@linux.vnet.ibm.com; Ruifeng Wang <Ruifeng.Wang@arm.com>;
> Dharmik Thakkar <Dharmik.Thakkar@arm.com>; stable@dpdk.org; nd
> <nd@arm.com>; jerinj@marvell.com; Honnappa Nagarahalli
> <Honnappa.Nagarahalli@arm.com>; nd <nd@arm.com>
> Subject: RE: [PATCH 1/3] eventdev: fix race condition on timer list counter
> 
> <snip>
> > >
> > > >
> > > > Hi Phil,
> > > >
> > > > Good catch - thanks for the fix.   I've commented in-line:
> > > >
> > > > > -----Original Message-----
> > > > > From: Phil Yang <phil.yang@arm.com>
> > > > > Sent: Friday, June 12, 2020 6:20 AM
> > > > > To: dev@dpdk.org; Carrillo, Erik G <erik.g.carrillo@intel.com>
> > > > > Cc: drc@linux.vnet.ibm.com; honnappa.nagarahalli@arm.com;
> > > > > ruifeng.wang@arm.com; dharmik.thakkar@arm.com; nd@arm.com;
> > > > > stable@dpdk.org
> > > > > Subject: [PATCH 1/3] eventdev: fix race condition on timer list
> > > > > counter
> > > > >
> > > > > The n_poll_lcores counter and poll_lcore array are shared
> > > > > between lcores and the update of these variables are out of the
> > > > > protection of spinlock on each lcore timer list. The
> > > > > read-modify-write operations of the counter are not atomic, so
> > > > > it has the potential of race condition
> > > > between lcores.
> > > > >
> > > > > Use c11 atomics with RELAXED ordering to prevent confliction.
> > > > >
> > > > > Fixes: cc7b73ea9e3b ("eventdev: add new software timer adapter")
> > > > > Cc: erik.g.carrillo@intel.com
> > > > > Cc: stable@dpdk.org
> > > > >
> > > > > Signed-off-by: Phil Yang <phil.yang@arm.com>
> > > > > Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
> > > > > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > > > > ---
> > > > >  lib/librte_eventdev/rte_event_timer_adapter.c | 16
> > > > > ++++++++++++----
> > > > >  1 file changed, 12 insertions(+), 4 deletions(-)
> > > > >
> > > > > diff --git a/lib/librte_eventdev/rte_event_timer_adapter.c
> > > > > b/lib/librte_eventdev/rte_event_timer_adapter.c
> > > > > index 005459f..6a0e283 100644
> > > > > --- a/lib/librte_eventdev/rte_event_timer_adapter.c
> > > > > +++ b/lib/librte_eventdev/rte_event_timer_adapter.c
> > > > > @@ -583,6 +583,7 @@ swtim_callback(struct rte_timer *tim)
> > > > > uint16_t nb_evs_invalid = 0;  uint64_t opaque;  int ret;
> > > > > +int n_lcores;
> > > > >
> > > > >  opaque = evtim->impl_opaque[1];  adapter = (struct
> > > > > rte_event_timer_adapter *)(uintptr_t)opaque; @@
> > > > > -605,8 +606,12 @@ swtim_callback(struct rte_timer *tim)
> > > > >        "with immediate expiry value");  }
> > > > >
> > > > > -if (unlikely(rte_atomic16_test_and_set(&sw-
> > > > > >in_use[lcore].v)))
> > > > > -sw->poll_lcores[sw->n_poll_lcores++] = lcore;
> > > > > +if (unlikely(rte_atomic16_test_and_set(&sw-
> > > > > >in_use[lcore].v))) {
> > > > > +n_lcores = __atomic_fetch_add(&sw->n_poll_lcores,
> > > > > 1,
> > > > > +__ATOMIC_RELAXED);
> > > Since this commit will be back ported, we should prefer to use
> > > rte_atomic APIs for this commit. Otherwise, we will have a mix of
> > > rte_atomic and C11 APIs.
> > > My suggestion is to fix this bug using rte_atomic so that backported
> > > code will have only rte_atomic APIs. Add another commit (if
> > > required) in this series to make the bug fix use C11 APIs (this
> > > commit will not be
> > backported).
> >
> > Hi Honnappa,
> >
> > It doesn't have an applicable rte_atomic_XXX API to fix this issue.
> > The rte_atomic32_inc doesn't return the original value of the input
> > parameter and rte_atomic32_add_return can only return the new value.
> Ok, understood.
> 
> >
> > Meanwhile, the rte_timer_alt_manage & rte_timer_stop_all API not
> > support rte_atomic type parameters. We might need to rewrite these two
> > APIs if we want to use rte_atomic operations for n_pol_lcores and
> poll_lcores array.
> >
> > So, a better solution could be to backport the entire c11 solution to
> > stable releases.
> I am ok with the approach.
> Erik, are you ok with this?
> 

Yes, I'm OK with that as well.

Thanks,
Erik

> >
> > Thanks,
> > Phil
> >
> > >
> > > >
> > > > Just a nit, but let's align the continued line with the opening
> > > > parentheses in this location and below.  With these changes:
> > > >
> > > > Acked-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com>
> > > >
> > > > > +__atomic_store_n(&sw->poll_lcores[n_lcores],
> > > > > lcore,
> > > > > +__ATOMIC_RELAXED);
> > > > > +}
> > > > >  } else {
> > > > >  EVTIM_BUF_LOG_DBG("buffered an event timer expiry event");
> > > > >
> > > > > @@ -1011,6 +1016,7 @@ __swtim_arm_burst(const struct
> > > > > rte_event_timer_adapter *adapter,  uint32_t lcore_id =
> > > > > rte_lcore_id();  struct rte_timer *tim, *tims[nb_evtims];
> > > > > uint64_t cycles;
> > > > > +int n_lcores;
> > > > >
> > > > >  #ifdef RTE_LIBRTE_EVENTDEV_DEBUG
> > > > >  /* Check that the service is running. */ @@ -1033,8 +1039,10 @@
> > > > > __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
> > > > > if
> > > > > (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore_id].v)))
> > > > > {  EVTIM_LOG_DBG("Adding lcore id = %u to list of lcores to
> > > > poll",
> > > > >        lcore_id);
> > > > > -sw->poll_lcores[sw->n_poll_lcores] = lcore_id;
> > > > > -++sw->n_poll_lcores;
> > > > > +n_lcores = __atomic_fetch_add(&sw->n_poll_lcores, 1,
> > > > > +__ATOMIC_RELAXED); __atomic_store_n(&sw-
> >poll_lcores[n_lcores],
> > > > > +lcore_id, __ATOMIC_RELAXED);
> > > > >  }
> > > > >
> > > > >  ret = rte_mempool_get_bulk(sw->tim_pool, (void **)tims,
> > > > > --
> > > > > 2.7.4
> > >


^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [dpdk-stable] [PATCH 1/3] eventdev: fix race condition on timer list counter
  2020-07-02 21:15         ` Carrillo, Erik G
@ 2020-07-02 21:30           ` Honnappa Nagarahalli
  0 siblings, 0 replies; 19+ messages in thread
From: Honnappa Nagarahalli @ 2020-07-02 21:30 UTC (permalink / raw)
  To: Carrillo, Erik G, Phil Yang, dev
  Cc: drc, Ruifeng Wang, Dharmik Thakkar, stable, nd, jerinj,
	Honnappa Nagarahalli, nd

<snip>

> > > >
> > > > >
> > > > > Hi Phil,
> > > > >
> > > > > Good catch - thanks for the fix.   I've commented in-line:
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: Phil Yang <phil.yang@arm.com>
> > > > > > Sent: Friday, June 12, 2020 6:20 AM
> > > > > > To: dev@dpdk.org; Carrillo, Erik G <erik.g.carrillo@intel.com>
> > > > > > Cc: drc@linux.vnet.ibm.com; honnappa.nagarahalli@arm.com;
> > > > > > ruifeng.wang@arm.com; dharmik.thakkar@arm.com; nd@arm.com;
> > > > > > stable@dpdk.org
> > > > > > Subject: [PATCH 1/3] eventdev: fix race condition on timer
> > > > > > list counter
> > > > > >
> > > > > > The n_poll_lcores counter and poll_lcore array are shared
> > > > > > between lcores and the update of these variables are out of
> > > > > > the protection of spinlock on each lcore timer list. The
> > > > > > read-modify-write operations of the counter are not atomic, so
> > > > > > it has the potential of race condition
> > > > > between lcores.
> > > > > >
> > > > > > Use c11 atomics with RELAXED ordering to prevent confliction.
> > > > > >
> > > > > > Fixes: cc7b73ea9e3b ("eventdev: add new software timer
> > > > > > adapter")
> > > > > > Cc: erik.g.carrillo@intel.com
> > > > > > Cc: stable@dpdk.org
> > > > > >
> > > > > > Signed-off-by: Phil Yang <phil.yang@arm.com>
> > > > > > Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
> > > > > > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > > > > > ---
> > > > > >  lib/librte_eventdev/rte_event_timer_adapter.c | 16
> > > > > > ++++++++++++----
> > > > > >  1 file changed, 12 insertions(+), 4 deletions(-)
> > > > > >
> > > > > > diff --git a/lib/librte_eventdev/rte_event_timer_adapter.c
> > > > > > b/lib/librte_eventdev/rte_event_timer_adapter.c
> > > > > > index 005459f..6a0e283 100644
> > > > > > --- a/lib/librte_eventdev/rte_event_timer_adapter.c
> > > > > > +++ b/lib/librte_eventdev/rte_event_timer_adapter.c
> > > > > > @@ -583,6 +583,7 @@ swtim_callback(struct rte_timer *tim)
> > > > > > uint16_t nb_evs_invalid = 0;  uint64_t opaque;  int ret;
> > > > > > +int n_lcores;
> > > > > >
> > > > > >  opaque = evtim->impl_opaque[1];  adapter = (struct
> > > > > > rte_event_timer_adapter *)(uintptr_t)opaque; @@
> > > > > > -605,8 +606,12 @@ swtim_callback(struct rte_timer *tim)
> > > > > >        "with immediate expiry value");  }
> > > > > >
> > > > > > -if (unlikely(rte_atomic16_test_and_set(&sw-
> > > > > > >in_use[lcore].v)))
> > > > > > -sw->poll_lcores[sw->n_poll_lcores++] = lcore;
> > > > > > +if (unlikely(rte_atomic16_test_and_set(&sw-
> > > > > > >in_use[lcore].v))) {
> > > > > > +n_lcores = __atomic_fetch_add(&sw->n_poll_lcores,
> > > > > > 1,
> > > > > > +__ATOMIC_RELAXED);
> > > > Since this commit will be back ported, we should prefer to use
> > > > rte_atomic APIs for this commit. Otherwise, we will have a mix of
> > > > rte_atomic and C11 APIs.
> > > > My suggestion is to fix this bug using rte_atomic so that
> > > > backported code will have only rte_atomic APIs. Add another commit
> > > > (if
> > > > required) in this series to make the bug fix use C11 APIs (this
> > > > commit will not be
> > > backported).
> > >
> > > Hi Honnappa,
> > >
> > > It doesn't have an applicable rte_atomic_XXX API to fix this issue.
> > > The rte_atomic32_inc doesn't return the original value of the input
> > > parameter and rte_atomic32_add_return can only return the new value.
> > Ok, understood.
> >
> > >
> > > Meanwhile, the rte_timer_alt_manage & rte_timer_stop_all API not
> > > support rte_atomic type parameters. We might need to rewrite these
> > > two APIs if we want to use rte_atomic operations for n_pol_lcores
> > > and
> > poll_lcores array.
> > >
> > > So, a better solution could be to backport the entire c11 solution
> > > to stable releases.
> > I am ok with the approach.
> > Erik, are you ok with this?
> >
> 
> Yes, I'm OK with that as well.
Thanks Erik. I think we need to add stable@dpdk.org to Cc for all the commits in the series.

> 
> Thanks,
> Erik
> 
> > >
> > > Thanks,
> > > Phil
> > >
> > > >
> > > > >
> > > > > Just a nit, but let's align the continued line with the opening
> > > > > parentheses in this location and below.  With these changes:
> > > > >
> > > > > Acked-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com>
> > > > >
> > > > > > +__atomic_store_n(&sw->poll_lcores[n_lcores],
> > > > > > lcore,
> > > > > > +__ATOMIC_RELAXED);
> > > > > > +}
> > > > > >  } else {
> > > > > >  EVTIM_BUF_LOG_DBG("buffered an event timer expiry event");
> > > > > >
> > > > > > @@ -1011,6 +1016,7 @@ __swtim_arm_burst(const struct
> > > > > > rte_event_timer_adapter *adapter,  uint32_t lcore_id =
> > > > > > rte_lcore_id();  struct rte_timer *tim, *tims[nb_evtims];
> > > > > > uint64_t cycles;
> > > > > > +int n_lcores;
> > > > > >
> > > > > >  #ifdef RTE_LIBRTE_EVENTDEV_DEBUG
> > > > > >  /* Check that the service is running. */ @@ -1033,8 +1039,10
> > > > > > @@ __swtim_arm_burst(const struct rte_event_timer_adapter
> > > > > > *adapter, if
> > > > > > (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore_id].v)))
> > > > > > {  EVTIM_LOG_DBG("Adding lcore id = %u to list of lcores to
> > > > > poll",
> > > > > >        lcore_id);
> > > > > > -sw->poll_lcores[sw->n_poll_lcores] = lcore_id;
> > > > > > -++sw->n_poll_lcores;
> > > > > > +n_lcores = __atomic_fetch_add(&sw->n_poll_lcores, 1,
> > > > > > +__ATOMIC_RELAXED); __atomic_store_n(&sw-
> > >poll_lcores[n_lcores],
> > > > > > +lcore_id, __ATOMIC_RELAXED);
> > > > > >  }
> > > > > >
> > > > > >  ret = rte_mempool_get_bulk(sw->tim_pool, (void **)tims,
> > > > > > --
> > > > > > 2.7.4
> > > >


^ permalink raw reply	[flat|nested] 19+ messages in thread

* [dpdk-stable] [PATCH v3 1/4] eventdev: fix race condition on timer list counter
  2020-07-02  5:26 ` [dpdk-stable] [PATCH v2 1/4] " Phil Yang
@ 2020-07-07 11:13   ` " Phil Yang
  2020-07-07 15:54     ` [dpdk-stable] [PATCH v4 " Phil Yang
  0 siblings, 1 reply; 19+ messages in thread
From: Phil Yang @ 2020-07-07 11:13 UTC (permalink / raw)
  To: thomas, erik.g.carrillo, dev
  Cc: jerinj, Honnappa.Nagarahalli, drc, Ruifeng.Wang, Dharmik.Thakkar,
	nd, david.marchand, mdr, nhorman, dodji, stable

The n_poll_lcores counter and poll_lcore array are shared between lcores
and the update of these variables are out of the protection of spinlock
on each lcore timer list. The read-modify-write operations of the counter
are not atomic, so it has the potential of race condition between lcores.

Use c11 atomics with RELAXED ordering to prevent confliction.

Fixes: cc7b73ea9e3b ("eventdev: add new software timer adapter")
Cc: erik.g.carrillo@intel.com
Cc: stable@dpdk.org

Signed-off-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Acked-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com>
---
v2:
Align the code. (Erik)

 lib/librte_eventdev/rte_event_timer_adapter.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/lib/librte_eventdev/rte_event_timer_adapter.c b/lib/librte_eventdev/rte_event_timer_adapter.c
index 2321803..370ea40 100644
--- a/lib/librte_eventdev/rte_event_timer_adapter.c
+++ b/lib/librte_eventdev/rte_event_timer_adapter.c
@@ -583,6 +583,7 @@ swtim_callback(struct rte_timer *tim)
 	uint16_t nb_evs_invalid = 0;
 	uint64_t opaque;
 	int ret;
+	int n_lcores;
 
 	opaque = evtim->impl_opaque[1];
 	adapter = (struct rte_event_timer_adapter *)(uintptr_t)opaque;
@@ -605,8 +606,12 @@ swtim_callback(struct rte_timer *tim)
 				      "with immediate expiry value");
 		}
 
-		if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore].v)))
-			sw->poll_lcores[sw->n_poll_lcores++] = lcore;
+		if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore].v))) {
+			n_lcores = __atomic_fetch_add(&sw->n_poll_lcores, 1,
+						     __ATOMIC_RELAXED);
+			__atomic_store_n(&sw->poll_lcores[n_lcores], lcore,
+					__ATOMIC_RELAXED);
+		}
 	} else {
 		EVTIM_BUF_LOG_DBG("buffered an event timer expiry event");
 
@@ -1011,6 +1016,7 @@ __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
 	uint32_t lcore_id = rte_lcore_id();
 	struct rte_timer *tim, *tims[nb_evtims];
 	uint64_t cycles;
+	int n_lcores;
 
 #ifdef RTE_LIBRTE_EVENTDEV_DEBUG
 	/* Check that the service is running. */
@@ -1033,8 +1039,10 @@ __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
 	if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore_id].v))) {
 		EVTIM_LOG_DBG("Adding lcore id = %u to list of lcores to poll",
 			      lcore_id);
-		sw->poll_lcores[sw->n_poll_lcores] = lcore_id;
-		++sw->n_poll_lcores;
+		n_lcores = __atomic_fetch_add(&sw->n_poll_lcores, 1,
+					     __ATOMIC_RELAXED);
+		__atomic_store_n(&sw->poll_lcores[n_lcores], lcore_id,
+				__ATOMIC_RELAXED);
 	}
 
 	ret = rte_mempool_get_bulk(sw->tim_pool, (void **)tims,
-- 
2.7.4


^ permalink raw reply	[flat|nested] 19+ messages in thread

* [dpdk-stable] [PATCH v4 1/4] eventdev: fix race condition on timer list counter
  2020-07-07 11:13   ` [dpdk-stable] [PATCH v3 " Phil Yang
@ 2020-07-07 15:54     ` " Phil Yang
  2020-07-07 15:54       ` [dpdk-stable] [PATCH v4 2/4] eventdev: use C11 atomics for lcore timer armed flag Phil Yang
                         ` (3 more replies)
  0 siblings, 4 replies; 19+ messages in thread
From: Phil Yang @ 2020-07-07 15:54 UTC (permalink / raw)
  To: jerinj, dev
  Cc: thomas, erik.g.carrillo, Honnappa.Nagarahalli, drc, Ruifeng.Wang,
	Dharmik.Thakkar, nd, david.marchand, mdr, nhorman, dodji, stable

The n_poll_lcores counter and poll_lcore array are shared between lcores
and the update of these variables are out of the protection of spinlock
on each lcore timer list. The read-modify-write operations of the counter
are not atomic, so it has the potential of race condition between lcores.

Use c11 atomics with RELAXED ordering to prevent confliction.

Fixes: cc7b73ea9e3b ("eventdev: add new software timer adapter")
Cc: erik.g.carrillo@intel.com
Cc: stable@dpdk.org

Signed-off-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Acked-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com>
---
v2:
Align the code. (Erik)

 lib/librte_eventdev/rte_event_timer_adapter.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/lib/librte_eventdev/rte_event_timer_adapter.c b/lib/librte_eventdev/rte_event_timer_adapter.c
index 2321803..370ea40 100644
--- a/lib/librte_eventdev/rte_event_timer_adapter.c
+++ b/lib/librte_eventdev/rte_event_timer_adapter.c
@@ -583,6 +583,7 @@ swtim_callback(struct rte_timer *tim)
 	uint16_t nb_evs_invalid = 0;
 	uint64_t opaque;
 	int ret;
+	int n_lcores;
 
 	opaque = evtim->impl_opaque[1];
 	adapter = (struct rte_event_timer_adapter *)(uintptr_t)opaque;
@@ -605,8 +606,12 @@ swtim_callback(struct rte_timer *tim)
 				      "with immediate expiry value");
 		}
 
-		if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore].v)))
-			sw->poll_lcores[sw->n_poll_lcores++] = lcore;
+		if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore].v))) {
+			n_lcores = __atomic_fetch_add(&sw->n_poll_lcores, 1,
+						     __ATOMIC_RELAXED);
+			__atomic_store_n(&sw->poll_lcores[n_lcores], lcore,
+					__ATOMIC_RELAXED);
+		}
 	} else {
 		EVTIM_BUF_LOG_DBG("buffered an event timer expiry event");
 
@@ -1011,6 +1016,7 @@ __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
 	uint32_t lcore_id = rte_lcore_id();
 	struct rte_timer *tim, *tims[nb_evtims];
 	uint64_t cycles;
+	int n_lcores;
 
 #ifdef RTE_LIBRTE_EVENTDEV_DEBUG
 	/* Check that the service is running. */
@@ -1033,8 +1039,10 @@ __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
 	if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore_id].v))) {
 		EVTIM_LOG_DBG("Adding lcore id = %u to list of lcores to poll",
 			      lcore_id);
-		sw->poll_lcores[sw->n_poll_lcores] = lcore_id;
-		++sw->n_poll_lcores;
+		n_lcores = __atomic_fetch_add(&sw->n_poll_lcores, 1,
+					     __ATOMIC_RELAXED);
+		__atomic_store_n(&sw->poll_lcores[n_lcores], lcore_id,
+				__ATOMIC_RELAXED);
 	}
 
 	ret = rte_mempool_get_bulk(sw->tim_pool, (void **)tims,
-- 
2.7.4


^ permalink raw reply	[flat|nested] 19+ messages in thread

* [dpdk-stable] [PATCH v4 2/4] eventdev: use C11 atomics for lcore timer armed flag
  2020-07-07 15:54     ` [dpdk-stable] [PATCH v4 " Phil Yang
@ 2020-07-07 15:54       ` Phil Yang
  2020-07-07 15:54       ` [dpdk-stable] [PATCH v4 3/4] eventdev: remove redundant code Phil Yang
                         ` (2 subsequent siblings)
  3 siblings, 0 replies; 19+ messages in thread
From: Phil Yang @ 2020-07-07 15:54 UTC (permalink / raw)
  To: jerinj, dev
  Cc: thomas, erik.g.carrillo, Honnappa.Nagarahalli, drc, Ruifeng.Wang,
	Dharmik.Thakkar, nd, david.marchand, mdr, nhorman, dodji, stable

The in_use flag is a per core variable which is not shared between
lcores in the normal case and the access of this variable should be
ordered on the same core. However, if non-EAL thread pick the highest
lcore to insert timers into, there is the possibility of conflicts
on this flag between threads. Then the atomic compare-and-swap
operation is needed.

Use the C11 atomics instead of the generic rte_atomic operations to
avoid the unnecessary barrier on aarch64.

Cc: stable@dpdk.org

Signed-off-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Acked-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com>
---
v4:
1.Change 'CAS' to 'compare-and-swap' to pass the coding style check.
2.Cc to stable release. (Honnappa)

v2:
1. Make the code comments more accurate. (Erik)
2. Define the in_use flag as an unsigned type. (Stephen)

 lib/librte_eventdev/rte_event_timer_adapter.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/lib/librte_eventdev/rte_event_timer_adapter.c b/lib/librte_eventdev/rte_event_timer_adapter.c
index 370ea40..4ed3013 100644
--- a/lib/librte_eventdev/rte_event_timer_adapter.c
+++ b/lib/librte_eventdev/rte_event_timer_adapter.c
@@ -554,7 +554,7 @@ struct swtim {
 	uint32_t timer_data_id;
 	/* Track which cores have actually armed a timer */
 	struct {
-		rte_atomic16_t v;
+		uint16_t v;
 	} __rte_cache_aligned in_use[RTE_MAX_LCORE];
 	/* Track which cores' timer lists should be polled */
 	unsigned int poll_lcores[RTE_MAX_LCORE];
@@ -606,7 +606,8 @@ swtim_callback(struct rte_timer *tim)
 				      "with immediate expiry value");
 		}
 
-		if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore].v))) {
+		if (unlikely(sw->in_use[lcore].v == 0)) {
+			sw->in_use[lcore].v = 1;
 			n_lcores = __atomic_fetch_add(&sw->n_poll_lcores, 1,
 						     __ATOMIC_RELAXED);
 			__atomic_store_n(&sw->poll_lcores[n_lcores], lcore,
@@ -834,7 +835,7 @@ swtim_init(struct rte_event_timer_adapter *adapter)
 
 	/* Initialize the variables that track in-use timer lists */
 	for (i = 0; i < RTE_MAX_LCORE; i++)
-		rte_atomic16_init(&sw->in_use[i].v);
+		sw->in_use[i].v = 0;
 
 	/* Initialize the timer subsystem and allocate timer data instance */
 	ret = rte_timer_subsystem_init();
@@ -1017,6 +1018,8 @@ __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
 	struct rte_timer *tim, *tims[nb_evtims];
 	uint64_t cycles;
 	int n_lcores;
+	/* Timer list for this lcore is not in use. */
+	uint16_t exp_state = 0;
 
 #ifdef RTE_LIBRTE_EVENTDEV_DEBUG
 	/* Check that the service is running. */
@@ -1035,8 +1038,12 @@ __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
 	/* If this is the first time we're arming an event timer on this lcore,
 	 * mark this lcore as "in use"; this will cause the service
 	 * function to process the timer list that corresponds to this lcore.
+	 * The atomic compare-and-swap operation can prevent the race condition
+	 * on in_use flag between multiple non-EAL threads.
 	 */
-	if (unlikely(rte_atomic16_test_and_set(&sw->in_use[lcore_id].v))) {
+	if (unlikely(__atomic_compare_exchange_n(&sw->in_use[lcore_id].v,
+			&exp_state, 1, 0,
+			__ATOMIC_RELAXED, __ATOMIC_RELAXED))) {
 		EVTIM_LOG_DBG("Adding lcore id = %u to list of lcores to poll",
 			      lcore_id);
 		n_lcores = __atomic_fetch_add(&sw->n_poll_lcores, 1,
-- 
2.7.4


^ permalink raw reply	[flat|nested] 19+ messages in thread

* [dpdk-stable] [PATCH v4 3/4] eventdev: remove redundant code
  2020-07-07 15:54     ` [dpdk-stable] [PATCH v4 " Phil Yang
  2020-07-07 15:54       ` [dpdk-stable] [PATCH v4 2/4] eventdev: use C11 atomics for lcore timer armed flag Phil Yang
@ 2020-07-07 15:54       ` Phil Yang
  2020-07-07 15:54       ` [dpdk-stable] [PATCH v4 4/4] eventdev: relax smp barriers with C11 atomics Phil Yang
  2020-07-08 13:30       ` [dpdk-stable] [dpdk-dev] [PATCH v4 1/4] eventdev: fix race condition on timer list counter Jerin Jacob
  3 siblings, 0 replies; 19+ messages in thread
From: Phil Yang @ 2020-07-07 15:54 UTC (permalink / raw)
  To: jerinj, dev
  Cc: thomas, erik.g.carrillo, Honnappa.Nagarahalli, drc, Ruifeng.Wang,
	Dharmik.Thakkar, nd, david.marchand, mdr, nhorman, dodji, stable

There is no thread will access these impl_opaque data after timer
canceled. When new timer armed, it got refilled. So the cleanup
process is unnecessary.

Cc: stable@dpdk.org

Signed-off-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
---
v4:
Cc to stable release. (Honnappa)

 lib/librte_eventdev/rte_event_timer_adapter.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/lib/librte_eventdev/rte_event_timer_adapter.c b/lib/librte_eventdev/rte_event_timer_adapter.c
index 4ed3013..aa01b4d 100644
--- a/lib/librte_eventdev/rte_event_timer_adapter.c
+++ b/lib/librte_eventdev/rte_event_timer_adapter.c
@@ -1167,8 +1167,6 @@ swtim_cancel_burst(const struct rte_event_timer_adapter *adapter,
 		rte_mempool_put(sw->tim_pool, (void **)timp);
 
 		evtims[i]->state = RTE_EVENT_TIMER_CANCELED;
-		evtims[i]->impl_opaque[0] = 0;
-		evtims[i]->impl_opaque[1] = 0;
 
 		rte_smp_wmb();
 	}
-- 
2.7.4


^ permalink raw reply	[flat|nested] 19+ messages in thread

* [dpdk-stable] [PATCH v4 4/4] eventdev: relax smp barriers with C11 atomics
  2020-07-07 15:54     ` [dpdk-stable] [PATCH v4 " Phil Yang
  2020-07-07 15:54       ` [dpdk-stable] [PATCH v4 2/4] eventdev: use C11 atomics for lcore timer armed flag Phil Yang
  2020-07-07 15:54       ` [dpdk-stable] [PATCH v4 3/4] eventdev: remove redundant code Phil Yang
@ 2020-07-07 15:54       ` Phil Yang
  2020-07-08 13:30       ` [dpdk-stable] [dpdk-dev] [PATCH v4 1/4] eventdev: fix race condition on timer list counter Jerin Jacob
  3 siblings, 0 replies; 19+ messages in thread
From: Phil Yang @ 2020-07-07 15:54 UTC (permalink / raw)
  To: jerinj, dev
  Cc: thomas, erik.g.carrillo, Honnappa.Nagarahalli, drc, Ruifeng.Wang,
	Dharmik.Thakkar, nd, david.marchand, mdr, nhorman, dodji, stable

The impl_opaque field is shared between the timer arm and cancel
operations. Meanwhile, the state flag acts as a guard variable to
make sure the update of impl_opaque is synchronized. The original
code uses rte_smp barriers to achieve that. This patch uses C11
atomics with an explicit one-way memory barrier instead of full
barriers rte_smp_w/rmb() to avoid the unnecessary barrier on aarch64.

Since compilers can generate the same instructions for volatile and
non-volatile variable in C11 __atomics built-ins, so remain the volatile
keyword in front of state enum to avoid the ABI break issue.

Cc: stable@dpdk.org

Signed-off-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Acked-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com>
---
v4:
1. Fix typo.
2. Cc to stable release. (Honnappa)

v3:
Fix ABI issue: revert to 'volatile enum rte_event_timer_state type state'.

v2:
1. Removed implementation-specific opaque data cleanup code.
2. Replaced thread fence with atomic ACQURE/RELEASE ordering on state access.

 lib/librte_eventdev/rte_event_timer_adapter.c | 55 ++++++++++++++++++---------
 1 file changed, 37 insertions(+), 18 deletions(-)

diff --git a/lib/librte_eventdev/rte_event_timer_adapter.c b/lib/librte_eventdev/rte_event_timer_adapter.c
index aa01b4d..4c5e49e 100644
--- a/lib/librte_eventdev/rte_event_timer_adapter.c
+++ b/lib/librte_eventdev/rte_event_timer_adapter.c
@@ -629,7 +629,8 @@ swtim_callback(struct rte_timer *tim)
 		sw->expired_timers[sw->n_expired_timers++] = tim;
 		sw->stats.evtim_exp_count++;
 
-		evtim->state = RTE_EVENT_TIMER_NOT_ARMED;
+		__atomic_store_n(&evtim->state, RTE_EVENT_TIMER_NOT_ARMED,
+				__ATOMIC_RELEASE);
 	}
 
 	if (event_buffer_batch_ready(&sw->buffer)) {
@@ -1020,6 +1021,7 @@ __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
 	int n_lcores;
 	/* Timer list for this lcore is not in use. */
 	uint16_t exp_state = 0;
+	enum rte_event_timer_state n_state;
 
 #ifdef RTE_LIBRTE_EVENTDEV_DEBUG
 	/* Check that the service is running. */
@@ -1060,30 +1062,36 @@ __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
 	}
 
 	for (i = 0; i < nb_evtims; i++) {
-		/* Don't modify the event timer state in these cases */
-		if (evtims[i]->state == RTE_EVENT_TIMER_ARMED) {
+		n_state = __atomic_load_n(&evtims[i]->state, __ATOMIC_ACQUIRE);
+		if (n_state == RTE_EVENT_TIMER_ARMED) {
 			rte_errno = EALREADY;
 			break;
-		} else if (!(evtims[i]->state == RTE_EVENT_TIMER_NOT_ARMED ||
-			     evtims[i]->state == RTE_EVENT_TIMER_CANCELED)) {
+		} else if (!(n_state == RTE_EVENT_TIMER_NOT_ARMED ||
+			     n_state == RTE_EVENT_TIMER_CANCELED)) {
 			rte_errno = EINVAL;
 			break;
 		}
 
 		ret = check_timeout(evtims[i], adapter);
 		if (unlikely(ret == -1)) {
-			evtims[i]->state = RTE_EVENT_TIMER_ERROR_TOOLATE;
+			__atomic_store_n(&evtims[i]->state,
+					RTE_EVENT_TIMER_ERROR_TOOLATE,
+					__ATOMIC_RELAXED);
 			rte_errno = EINVAL;
 			break;
 		} else if (unlikely(ret == -2)) {
-			evtims[i]->state = RTE_EVENT_TIMER_ERROR_TOOEARLY;
+			__atomic_store_n(&evtims[i]->state,
+					RTE_EVENT_TIMER_ERROR_TOOEARLY,
+					__ATOMIC_RELAXED);
 			rte_errno = EINVAL;
 			break;
 		}
 
 		if (unlikely(check_destination_event_queue(evtims[i],
 							   adapter) < 0)) {
-			evtims[i]->state = RTE_EVENT_TIMER_ERROR;
+			__atomic_store_n(&evtims[i]->state,
+					RTE_EVENT_TIMER_ERROR,
+					__ATOMIC_RELAXED);
 			rte_errno = EINVAL;
 			break;
 		}
@@ -1099,13 +1107,18 @@ __swtim_arm_burst(const struct rte_event_timer_adapter *adapter,
 					  SINGLE, lcore_id, NULL, evtims[i]);
 		if (ret < 0) {
 			/* tim was in RUNNING or CONFIG state */
-			evtims[i]->state = RTE_EVENT_TIMER_ERROR;
+			__atomic_store_n(&evtims[i]->state,
+					RTE_EVENT_TIMER_ERROR,
+					__ATOMIC_RELEASE);
 			break;
 		}
 
-		rte_smp_wmb();
 		EVTIM_LOG_DBG("armed an event timer");
-		evtims[i]->state = RTE_EVENT_TIMER_ARMED;
+		/* RELEASE ordering guarantees the adapter specific value
+		 * changes observed before the update of state.
+		 */
+		__atomic_store_n(&evtims[i]->state, RTE_EVENT_TIMER_ARMED,
+				__ATOMIC_RELEASE);
 	}
 
 	if (i < nb_evtims)
@@ -1132,6 +1145,7 @@ swtim_cancel_burst(const struct rte_event_timer_adapter *adapter,
 	struct rte_timer *timp;
 	uint64_t opaque;
 	struct swtim *sw = swtim_pmd_priv(adapter);
+	enum rte_event_timer_state n_state;
 
 #ifdef RTE_LIBRTE_EVENTDEV_DEBUG
 	/* Check that the service is running. */
@@ -1143,16 +1157,18 @@ swtim_cancel_burst(const struct rte_event_timer_adapter *adapter,
 
 	for (i = 0; i < nb_evtims; i++) {
 		/* Don't modify the event timer state in these cases */
-		if (evtims[i]->state == RTE_EVENT_TIMER_CANCELED) {
+		/* ACQUIRE ordering guarantees the access of implementation
+		 * specific opaque data under the correct state.
+		 */
+		n_state = __atomic_load_n(&evtims[i]->state, __ATOMIC_ACQUIRE);
+		if (n_state == RTE_EVENT_TIMER_CANCELED) {
 			rte_errno = EALREADY;
 			break;
-		} else if (evtims[i]->state != RTE_EVENT_TIMER_ARMED) {
+		} else if (n_state != RTE_EVENT_TIMER_ARMED) {
 			rte_errno = EINVAL;
 			break;
 		}
 
-		rte_smp_rmb();
-
 		opaque = evtims[i]->impl_opaque[0];
 		timp = (struct rte_timer *)(uintptr_t)opaque;
 		RTE_ASSERT(timp != NULL);
@@ -1166,9 +1182,12 @@ swtim_cancel_burst(const struct rte_event_timer_adapter *adapter,
 
 		rte_mempool_put(sw->tim_pool, (void **)timp);
 
-		evtims[i]->state = RTE_EVENT_TIMER_CANCELED;
-
-		rte_smp_wmb();
+		/* The RELEASE ordering here pairs with atomic ordering
+		 * to make sure the state update data observed between
+		 * threads.
+		 */
+		__atomic_store_n(&evtims[i]->state, RTE_EVENT_TIMER_CANCELED,
+				__ATOMIC_RELEASE);
 	}
 
 	return i;
-- 
2.7.4


^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [dpdk-stable] [dpdk-dev] [PATCH v4 1/4] eventdev: fix race condition on timer list counter
  2020-07-07 15:54     ` [dpdk-stable] [PATCH v4 " Phil Yang
                         ` (2 preceding siblings ...)
  2020-07-07 15:54       ` [dpdk-stable] [PATCH v4 4/4] eventdev: relax smp barriers with C11 atomics Phil Yang
@ 2020-07-08 13:30       ` Jerin Jacob
  2020-07-08 15:01         ` Thomas Monjalon
  3 siblings, 1 reply; 19+ messages in thread
From: Jerin Jacob @ 2020-07-08 13:30 UTC (permalink / raw)
  To: Phil Yang
  Cc: Jerin Jacob, dpdk-dev, Thomas Monjalon, Erik Gabriel Carrillo,
	Honnappa Nagarahalli, David Christensen,
	Ruifeng Wang (Arm Technology China),
	Dharmik Thakkar, nd, David Marchand, Ray Kinsella, Neil Horman,
	dodji, dpdk stable

On Tue, Jul 7, 2020 at 9:25 PM Phil Yang <phil.yang@arm.com> wrote:
>
> The n_poll_lcores counter and poll_lcore array are shared between lcores
> and the update of these variables are out of the protection of spinlock
> on each lcore timer list. The read-modify-write operations of the counter
> are not atomic, so it has the potential of race condition between lcores.
>
> Use c11 atomics with RELAXED ordering to prevent confliction.
>
> Fixes: cc7b73ea9e3b ("eventdev: add new software timer adapter")
> Cc: erik.g.carrillo@intel.com
> Cc: stable@dpdk.org
>
> Signed-off-by: Phil Yang <phil.yang@arm.com>
> Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> Acked-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com>

Hi Thomas,

The latest version does not have ABI breakage issue.

I have added the ABI verifier in my local patch verification setup.

Series applied to dpdk-next-eventdev/master.

Please pull this series from dpdk-next-eventdev/master. Thanks.

I am marking this patch series as "Awaiting Upstream" in patchwork
status to reflect the actual status.

^ permalink raw reply	[flat|nested] 19+ messages in thread

* Re: [dpdk-stable] [dpdk-dev] [PATCH v4 1/4] eventdev: fix race condition on timer list counter
  2020-07-08 13:30       ` [dpdk-stable] [dpdk-dev] [PATCH v4 1/4] eventdev: fix race condition on timer list counter Jerin Jacob
@ 2020-07-08 15:01         ` Thomas Monjalon
  0 siblings, 0 replies; 19+ messages in thread
From: Thomas Monjalon @ 2020-07-08 15:01 UTC (permalink / raw)
  To: Phil Yang, Jerin Jacob
  Cc: dev, Erik Gabriel Carrillo, Honnappa Nagarahalli,
	David Christensen, Ruifeng Wang (Arm Technology China),
	Dharmik Thakkar, nd, David Marchand, Ray Kinsella, Neil Horman,
	dodji, dpdk stable, Jerin Jacob

08/07/2020 15:30, Jerin Jacob:
> On Tue, Jul 7, 2020 at 9:25 PM Phil Yang <phil.yang@arm.com> wrote:
> >
> > The n_poll_lcores counter and poll_lcore array are shared between lcores
> > and the update of these variables are out of the protection of spinlock
> > on each lcore timer list. The read-modify-write operations of the counter
> > are not atomic, so it has the potential of race condition between lcores.
> >
> > Use c11 atomics with RELAXED ordering to prevent confliction.
> >
> > Fixes: cc7b73ea9e3b ("eventdev: add new software timer adapter")
> > Cc: erik.g.carrillo@intel.com
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Phil Yang <phil.yang@arm.com>
> > Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
> > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > Acked-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com>
> 
> Hi Thomas,
> 
> The latest version does not have ABI breakage issue.
> 
> I have added the ABI verifier in my local patch verification setup.
> 
> Series applied to dpdk-next-eventdev/master.
> 
> Please pull this series from dpdk-next-eventdev/master. Thanks.
> 
> I am marking this patch series as "Awaiting Upstream" in patchwork
> status to reflect the actual status.

OK, pulled and marked as Accepted in patchwork.



^ permalink raw reply	[flat|nested] 19+ messages in thread

end of thread, back to index

Thread overview: 19+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-06-12 11:19 [dpdk-stable] [PATCH 1/3] eventdev: fix race condition on timer list counter Phil Yang
2020-06-18 15:17 ` Carrillo, Erik G
2020-06-18 18:25   ` Honnappa Nagarahalli
2020-06-22  9:48     ` Phil Yang
2020-07-01 11:22       ` [dpdk-stable] [dpdk-dev] " Jerin Jacob
2020-07-02  3:28         ` Phil Yang
2020-07-02  3:26     ` [dpdk-stable] " Phil Yang
2020-07-02  3:56       ` Honnappa Nagarahalli
2020-07-02 21:15         ` Carrillo, Erik G
2020-07-02 21:30           ` Honnappa Nagarahalli
2020-06-22  9:09   ` Phil Yang
2020-07-02  5:26 ` [dpdk-stable] [PATCH v2 1/4] " Phil Yang
2020-07-07 11:13   ` [dpdk-stable] [PATCH v3 " Phil Yang
2020-07-07 15:54     ` [dpdk-stable] [PATCH v4 " Phil Yang
2020-07-07 15:54       ` [dpdk-stable] [PATCH v4 2/4] eventdev: use C11 atomics for lcore timer armed flag Phil Yang
2020-07-07 15:54       ` [dpdk-stable] [PATCH v4 3/4] eventdev: remove redundant code Phil Yang
2020-07-07 15:54       ` [dpdk-stable] [PATCH v4 4/4] eventdev: relax smp barriers with C11 atomics Phil Yang
2020-07-08 13:30       ` [dpdk-stable] [dpdk-dev] [PATCH v4 1/4] eventdev: fix race condition on timer list counter Jerin Jacob
2020-07-08 15:01         ` Thomas Monjalon

patches for DPDK stable branches

Archives are clonable:
	git clone --mirror http://inbox.dpdk.org/stable/0 stable/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 stable stable/ http://inbox.dpdk.org/stable \
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	public-inbox-index stable


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