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eal: fix race in control thread creation

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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: 3a0d465d4c ("eal: fix use-after-free on control thread creation")
Cc: stable@dpdk.org

Signed-off-by: Luc Pelletier <lucp.at.work@gmail.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
This commit is contained in:
Luc Pelletier 2021-04-07 16:16:04 -04:00 committed by David Marchand
parent 76d409ce6e
commit 34cc55cce6
1 changed files with 27 additions and 22 deletions
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49
lib/librte_eal/common/eal_common_thread.c
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@ -170,11 +170,19 @@ 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(&params->refcnt, 1, __ATOMIC_ACQ_REL) == 0) {
pthread_barrier_destroy(&params->configured);
free(params);
}
}
static void *ctrl_thread_init(void *arg)
{
int ret;
struct internal_config *internal_conf =
eal_get_internal_configuration();
rte_cpuset_t *cpuset = &internal_conf->ctrl_cpuset;
@ -184,11 +192,8 @@ static void *ctrl_thread_init(void *arg)
__rte_thread_init(rte_lcore_id(), cpuset);
ret = pthread_barrier_wait(&params->configured);
if (ret == PTHREAD_BARRIER_SERIAL_THREAD) {
pthread_barrier_destroy(&params->configured);
free(params);
}
pthread_barrier_wait(&params->configured);
ctrl_params_free(params);
return start_routine(routine_arg);
}
@ -210,15 +215,18 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name,
params->start_routine = start_routine;
params->arg = arg;
params->refcnt = 2;
pthread_barrier_init(&params->configured, NULL, 2);
ret = pthread_create(thread, attr, ctrl_thread_init, (void *)params);
ret = pthread_barrier_init(&params->configured, NULL, 2);
if (ret != 0) {
free(params);
return -ret;
}
ret = pthread_create(thread, attr, ctrl_thread_init, (void *)params);
if (ret != 0)
goto fail;
if (name != NULL) {
ret = rte_thread_setname(*thread, name);
if (ret < 0)
@ -227,25 +235,22 @@ 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(&params->configured);
if (ret == PTHREAD_BARRIER_SERIAL_THREAD) {
pthread_barrier_destroy(&params->configured);
free(params);
}
pthread_barrier_wait(&params->configured);
ctrl_params_free(params);
return 0;
fail:
if (PTHREAD_BARRIER_SERIAL_THREAD ==
pthread_barrier_wait(&params->configured)) {
pthread_barrier_destroy(&params->configured);
free(params);
}
fail_cancel:
pthread_cancel(*thread);
pthread_join(*thread, NULL);
fail:
pthread_barrier_destroy(&params->configured);
free(params);
return -ret;
}