From: Luc Pelletier <lucp.at.work@gmail.com>
To: christian.ehrhardt@canonical.com, stable@dpdk.org
Cc: Luc Pelletier <lucp.at.work@gmail.com>
Subject: [dpdk-stable] [PATCH 19.11.9 1/2] eal: fix race in control thread creation
Date: Fri, 21 May 2021 11:49:06 -0400 [thread overview]
Message-ID: <20210521154907.320565-1-lucp.at.work@gmail.com> (raw)
[ 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
next reply other threads:[~2021-05-21 15:49 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-21 15:49 Luc Pelletier [this message]
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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