* [dpdk-stable] [PATCH 19.11.9 1/2] eal: fix race in control thread creation
@ 2021-05-21 15:49 Luc Pelletier
2021-05-21 15:49 ` [dpdk-stable] [PATCH 19.11.9 2/2] eal: fix hang " Luc Pelletier
2021-06-03 4:59 ` [dpdk-stable] [PATCH 19.11.9 1/2] eal: fix race " Christian Ehrhardt
0 siblings, 2 replies; 4+ messages in thread
From: Luc Pelletier @ 2021-05-21 15:49 UTC (permalink / raw)
To: christian.ehrhardt, stable; +Cc: Luc Pelletier
[ upstream commit 34cc55cce6b180a6c3ee3fcf70a0fd56927f240d ]
The creation of control threads uses a pthread barrier for
synchronization. This patch fixes a race condition where the pthread
barrier could get destroyed while one of the threads has not yet
returned from the pthread_barrier_wait function, which could result in
undefined behaviour.
Fixes: 3a0d465d4c53 ("eal: fix use-after-free on control thread creation")
---
lib/librte_eal/common/eal_common_thread.c | 49 +++++++++++++----------
1 file changed, 27 insertions(+), 22 deletions(-)
diff --git a/lib/librte_eal/common/eal_common_thread.c b/lib/librte_eal/common/eal_common_thread.c
index f9a8cf14d..a5089ae49 100644
--- a/lib/librte_eal/common/eal_common_thread.c
+++ b/lib/librte_eal/common/eal_common_thread.c
@@ -147,20 +147,25 @@ struct rte_thread_ctrl_params {
void *(*start_routine)(void *);
void *arg;
pthread_barrier_t configured;
+ unsigned int refcnt;
};
+static void ctrl_params_free(struct rte_thread_ctrl_params *params)
+{
+ if (__atomic_sub_fetch(¶ms->refcnt, 1, __ATOMIC_ACQ_REL) == 0) {
+ (void)pthread_barrier_destroy(¶ms->configured);
+ free(params);
+ }
+}
+
static void *rte_thread_init(void *arg)
{
- int ret;
struct rte_thread_ctrl_params *params = arg;
void *(*start_routine)(void *) = params->start_routine;
void *routine_arg = params->arg;
- ret = pthread_barrier_wait(¶ms->configured);
- if (ret == PTHREAD_BARRIER_SERIAL_THREAD) {
- pthread_barrier_destroy(¶ms->configured);
- free(params);
- }
+ pthread_barrier_wait(¶ms->configured);
+ ctrl_params_free(params);
return start_routine(routine_arg);
}
@@ -180,15 +185,18 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name,
params->start_routine = start_routine;
params->arg = arg;
+ params->refcnt = 2;
- pthread_barrier_init(¶ms->configured, NULL, 2);
-
- ret = pthread_create(thread, attr, rte_thread_init, (void *)params);
+ ret = pthread_barrier_init(¶ms->configured, NULL, 2);
if (ret != 0) {
free(params);
return -ret;
}
+ ret = pthread_create(thread, attr, rte_thread_init, (void *)params);
+ if (ret != 0)
+ goto fail;
+
if (name != NULL) {
ret = rte_thread_setname(*thread, name);
if (ret < 0)
@@ -197,24 +205,21 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name,
}
ret = pthread_setaffinity_np(*thread, sizeof(*cpuset), cpuset);
- if (ret)
- goto fail;
+ if (ret != 0)
+ goto fail_cancel;
- ret = pthread_barrier_wait(¶ms->configured);
- if (ret == PTHREAD_BARRIER_SERIAL_THREAD) {
- pthread_barrier_destroy(¶ms->configured);
- free(params);
- }
+ pthread_barrier_wait(¶ms->configured);
+ ctrl_params_free(params);
return 0;
-fail:
- if (PTHREAD_BARRIER_SERIAL_THREAD ==
- pthread_barrier_wait(¶ms->configured)) {
- pthread_barrier_destroy(¶ms->configured);
- free(params);
- }
+fail_cancel:
pthread_cancel(*thread);
pthread_join(*thread, NULL);
+
+fail:
+ (void)pthread_barrier_destroy(¶ms->configured);
+ free(params);
+
return -ret;
}
--
2.25.1
^ permalink raw reply [flat|nested] 4+ messages in thread
* [dpdk-stable] [PATCH 19.11.9 2/2] eal: fix hang in control thread creation
2021-05-21 15:49 [dpdk-stable] [PATCH 19.11.9 1/2] eal: fix race in control thread creation Luc Pelletier
@ 2021-05-21 15:49 ` Luc Pelletier
2021-06-03 5:00 ` Christian Ehrhardt
2021-06-03 4:59 ` [dpdk-stable] [PATCH 19.11.9 1/2] eal: fix race " Christian Ehrhardt
1 sibling, 1 reply; 4+ messages in thread
From: Luc Pelletier @ 2021-05-21 15:49 UTC (permalink / raw)
To: christian.ehrhardt, stable; +Cc: Luc Pelletier
[ upstream commit af68c1d699be6c369e296b775bdbf13ae18b79cc ]
The affinity of a control thread is set after it has been launched. If
setting the affinity fails, pthread_cancel is called followed by a call
to pthread_join, which can hang forever if the thread's start routine
doesn't call a pthread cancellation point.
This patch modifies the logic so that the control thread exits
gracefully if the affinity cannot be set successfully and removes the
call to pthread_cancel.
Fixes: 6383d2642b62 ("eal: set name when creating a control thread")
---
lib/librte_eal/common/eal_common_thread.c | 29 +++++++++++++----------
1 file changed, 17 insertions(+), 12 deletions(-)
diff --git a/lib/librte_eal/common/eal_common_thread.c b/lib/librte_eal/common/eal_common_thread.c
index a5089ae49..b1e5c2a08 100644
--- a/lib/librte_eal/common/eal_common_thread.c
+++ b/lib/librte_eal/common/eal_common_thread.c
@@ -161,12 +161,16 @@ static void ctrl_params_free(struct rte_thread_ctrl_params *params)
static void *rte_thread_init(void *arg)
{
struct rte_thread_ctrl_params *params = arg;
- void *(*start_routine)(void *) = params->start_routine;
+ void *(*start_routine)(void *);
void *routine_arg = params->arg;
pthread_barrier_wait(¶ms->configured);
+ start_routine = params->start_routine;
ctrl_params_free(params);
+ if (start_routine == NULL)
+ return NULL;
+
return start_routine(routine_arg);
}
@@ -188,14 +192,12 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name,
params->refcnt = 2;
ret = pthread_barrier_init(¶ms->configured, NULL, 2);
- if (ret != 0) {
- free(params);
- return -ret;
- }
+ if (ret != 0)
+ goto fail_no_barrier;
ret = pthread_create(thread, attr, rte_thread_init, (void *)params);
if (ret != 0)
- goto fail;
+ goto fail_with_barrier;
if (name != NULL) {
ret = rte_thread_setname(*thread, name);
@@ -206,19 +208,22 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name,
ret = pthread_setaffinity_np(*thread, sizeof(*cpuset), cpuset);
if (ret != 0)
- goto fail_cancel;
+ params->start_routine = NULL;
pthread_barrier_wait(¶ms->configured);
ctrl_params_free(params);
- return 0;
+ if (ret != 0)
+ /* start_routine has been set to NULL above; */
+ /* ctrl thread will exit immediately */
+ pthread_join(*thread, NULL);
-fail_cancel:
- pthread_cancel(*thread);
- pthread_join(*thread, NULL);
+ return -ret;
-fail:
+fail_with_barrier:
(void)pthread_barrier_destroy(¶ms->configured);
+
+fail_no_barrier:
free(params);
return -ret;
--
2.25.1
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [dpdk-stable] [PATCH 19.11.9 2/2] eal: fix hang in control thread creation
2021-05-21 15:49 ` [dpdk-stable] [PATCH 19.11.9 2/2] eal: fix hang " Luc Pelletier
@ 2021-06-03 5:00 ` Christian Ehrhardt
0 siblings, 0 replies; 4+ messages in thread
From: Christian Ehrhardt @ 2021-06-03 5:00 UTC (permalink / raw)
To: Luc Pelletier; +Cc: dpdk stable
On Fri, May 21, 2021 at 5:49 PM Luc Pelletier <lucp.at.work@gmail.com> wrote:
>
> [ upstream commit af68c1d699be6c369e296b775bdbf13ae18b79cc ]
>
> The affinity of a control thread is set after it has been launched. If
> setting the affinity fails, pthread_cancel is called followed by a call
> to pthread_join, which can hang forever if the thread's start routine
> doesn't call a pthread cancellation point.
>
> This patch modifies the logic so that the control thread exits
> gracefully if the affinity cannot be set successfully and removes the
> call to pthread_cancel.
>
> Fixes: 6383d2642b62 ("eal: set name when creating a control thread")
> ---
Thank you, applied to 19.11.9 (to become -rc2) now
> lib/librte_eal/common/eal_common_thread.c | 29 +++++++++++++----------
> 1 file changed, 17 insertions(+), 12 deletions(-)
>
> diff --git a/lib/librte_eal/common/eal_common_thread.c b/lib/librte_eal/common/eal_common_thread.c
> index a5089ae49..b1e5c2a08 100644
> --- a/lib/librte_eal/common/eal_common_thread.c
> +++ b/lib/librte_eal/common/eal_common_thread.c
> @@ -161,12 +161,16 @@ static void ctrl_params_free(struct rte_thread_ctrl_params *params)
> static void *rte_thread_init(void *arg)
> {
> struct rte_thread_ctrl_params *params = arg;
> - void *(*start_routine)(void *) = params->start_routine;
> + void *(*start_routine)(void *);
> void *routine_arg = params->arg;
>
> pthread_barrier_wait(¶ms->configured);
> + start_routine = params->start_routine;
> ctrl_params_free(params);
>
> + if (start_routine == NULL)
> + return NULL;
> +
> return start_routine(routine_arg);
> }
>
> @@ -188,14 +192,12 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name,
> params->refcnt = 2;
>
> ret = pthread_barrier_init(¶ms->configured, NULL, 2);
> - if (ret != 0) {
> - free(params);
> - return -ret;
> - }
> + if (ret != 0)
> + goto fail_no_barrier;
>
> ret = pthread_create(thread, attr, rte_thread_init, (void *)params);
> if (ret != 0)
> - goto fail;
> + goto fail_with_barrier;
>
> if (name != NULL) {
> ret = rte_thread_setname(*thread, name);
> @@ -206,19 +208,22 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name,
>
> ret = pthread_setaffinity_np(*thread, sizeof(*cpuset), cpuset);
> if (ret != 0)
> - goto fail_cancel;
> + params->start_routine = NULL;
>
> pthread_barrier_wait(¶ms->configured);
> ctrl_params_free(params);
>
> - return 0;
> + if (ret != 0)
> + /* start_routine has been set to NULL above; */
> + /* ctrl thread will exit immediately */
> + pthread_join(*thread, NULL);
>
> -fail_cancel:
> - pthread_cancel(*thread);
> - pthread_join(*thread, NULL);
> + return -ret;
>
> -fail:
> +fail_with_barrier:
> (void)pthread_barrier_destroy(¶ms->configured);
> +
> +fail_no_barrier:
> free(params);
>
> return -ret;
> --
> 2.25.1
>
--
Christian Ehrhardt
Staff Engineer, Ubuntu Server
Canonical Ltd
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [dpdk-stable] [PATCH 19.11.9 1/2] eal: fix race in control thread creation
2021-05-21 15:49 [dpdk-stable] [PATCH 19.11.9 1/2] eal: fix race in control thread creation Luc Pelletier
2021-05-21 15:49 ` [dpdk-stable] [PATCH 19.11.9 2/2] eal: fix hang " Luc Pelletier
@ 2021-06-03 4:59 ` Christian Ehrhardt
1 sibling, 0 replies; 4+ messages in thread
From: Christian Ehrhardt @ 2021-06-03 4:59 UTC (permalink / raw)
To: Luc Pelletier; +Cc: dpdk stable
On Fri, May 21, 2021 at 5:49 PM Luc Pelletier <lucp.at.work@gmail.com> wrote:
>
> [ upstream commit 34cc55cce6b180a6c3ee3fcf70a0fd56927f240d ]
>
> The creation of control threads uses a pthread barrier for
> synchronization. This patch fixes a race condition where the pthread
> barrier could get destroyed while one of the threads has not yet
> returned from the pthread_barrier_wait function, which could result in
> undefined behaviour.
>
> Fixes: 3a0d465d4c53 ("eal: fix use-after-free on control thread creation")
> ---
Thank you, applied to 19.11.9 (to become -rc2) now
> lib/librte_eal/common/eal_common_thread.c | 49 +++++++++++++----------
> 1 file changed, 27 insertions(+), 22 deletions(-)
>
> diff --git a/lib/librte_eal/common/eal_common_thread.c b/lib/librte_eal/common/eal_common_thread.c
> index f9a8cf14d..a5089ae49 100644
> --- a/lib/librte_eal/common/eal_common_thread.c
> +++ b/lib/librte_eal/common/eal_common_thread.c
> @@ -147,20 +147,25 @@ struct rte_thread_ctrl_params {
> void *(*start_routine)(void *);
> void *arg;
> pthread_barrier_t configured;
> + unsigned int refcnt;
> };
>
> +static void ctrl_params_free(struct rte_thread_ctrl_params *params)
> +{
> + if (__atomic_sub_fetch(¶ms->refcnt, 1, __ATOMIC_ACQ_REL) == 0) {
> + (void)pthread_barrier_destroy(¶ms->configured);
> + free(params);
> + }
> +}
> +
> static void *rte_thread_init(void *arg)
> {
> - int ret;
> struct rte_thread_ctrl_params *params = arg;
> void *(*start_routine)(void *) = params->start_routine;
> void *routine_arg = params->arg;
>
> - ret = pthread_barrier_wait(¶ms->configured);
> - if (ret == PTHREAD_BARRIER_SERIAL_THREAD) {
> - pthread_barrier_destroy(¶ms->configured);
> - free(params);
> - }
> + pthread_barrier_wait(¶ms->configured);
> + ctrl_params_free(params);
>
> return start_routine(routine_arg);
> }
> @@ -180,15 +185,18 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name,
>
> params->start_routine = start_routine;
> params->arg = arg;
> + params->refcnt = 2;
>
> - pthread_barrier_init(¶ms->configured, NULL, 2);
> -
> - ret = pthread_create(thread, attr, rte_thread_init, (void *)params);
> + ret = pthread_barrier_init(¶ms->configured, NULL, 2);
> if (ret != 0) {
> free(params);
> return -ret;
> }
>
> + ret = pthread_create(thread, attr, rte_thread_init, (void *)params);
> + if (ret != 0)
> + goto fail;
> +
> if (name != NULL) {
> ret = rte_thread_setname(*thread, name);
> if (ret < 0)
> @@ -197,24 +205,21 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name,
> }
>
> ret = pthread_setaffinity_np(*thread, sizeof(*cpuset), cpuset);
> - if (ret)
> - goto fail;
> + if (ret != 0)
> + goto fail_cancel;
>
> - ret = pthread_barrier_wait(¶ms->configured);
> - if (ret == PTHREAD_BARRIER_SERIAL_THREAD) {
> - pthread_barrier_destroy(¶ms->configured);
> - free(params);
> - }
> + pthread_barrier_wait(¶ms->configured);
> + ctrl_params_free(params);
>
> return 0;
>
> -fail:
> - if (PTHREAD_BARRIER_SERIAL_THREAD ==
> - pthread_barrier_wait(¶ms->configured)) {
> - pthread_barrier_destroy(¶ms->configured);
> - free(params);
> - }
> +fail_cancel:
> pthread_cancel(*thread);
> pthread_join(*thread, NULL);
> +
> +fail:
> + (void)pthread_barrier_destroy(¶ms->configured);
> + free(params);
> +
> return -ret;
> }
> --
> 2.25.1
>
--
Christian Ehrhardt
Staff Engineer, Ubuntu Server
Canonical Ltd
^ permalink raw reply [flat|nested] 4+ messages in thread
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2021-05-21 15:49 [dpdk-stable] [PATCH 19.11.9 1/2] eal: fix race in control thread creation Luc Pelletier
2021-05-21 15:49 ` [dpdk-stable] [PATCH 19.11.9 2/2] eal: fix hang " Luc Pelletier
2021-06-03 5:00 ` Christian Ehrhardt
2021-06-03 4:59 ` [dpdk-stable] [PATCH 19.11.9 1/2] eal: fix race " Christian Ehrhardt
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