From: Luc Pelletier <lucp.at.work@gmail.com> To: Olivier Matz <olivier.matz@6wind.com> Cc: dev@dpdk.org, jianfeng.tan@intel.com, david.marchand@redhat.com, stable@dpdk.org Subject: Re: [dpdk-dev] [PATCH v2] eal: fix race in ctrl thread creation Date: Thu, 25 Mar 2021 10:42:38 -0400 Message-ID: <CAFeRdtA_5MXnCgxtXZUy6tBm3ZVQKu47Nu+6fWytSuM=9q_3Lg@mail.gmail.com> (raw) In-Reply-To: <20210325112731.16324-1-olivier.matz@6wind.com> Hi Olivier, > Thank you for reporting this problem and submitting the patch. > I think the issue can be fixed without any loop, like in this > patch. What do you think? I think getting rid of the loop is an excellent idea. Good thinking. Your version is much cleaner. > + __atomic_store_n(¶ms->barrier_refcnt, 2, __ATOMIC_RELEASE); I don't mean to nitpick but I don't think you need to use __atomic_store_n to initialize the refcnt. Either way is fine of course :) Thanks. Le jeu. 25 mars 2021 à 07:27, Olivier Matz <olivier.matz@6wind.com> a écrit : > > As reported by Luc, there is a race where the barrier is destroyed by > one thread, while the other thread did not yet leave > pthread_barrier_wait. > > This patch fixes the race condition by adding an atomic counter to > ensure that the barrier is destroyed only it is not used by any thread. > > Fixes: 3a0d465d4c53 ("eal: fix use-after-free on control thread creation") > Cc: jianfeng.tan@intel.com > Cc: stable@dpdk.org > > Reported-by: Luc Pelletier <lucp.at.work@gmail.com> > Signed-off-by: David Marchand <david.marchand@redhat.com> > Signed-off-by: Olivier Matz <olivier.matz@6wind.com> > --- > > Hi Luc, > > Thank you for reporting this problem and submitting the patch. > I think the issue can be fixed without any loop, like in this > patch. What do you think? > > Regards, > Olivier > > > lib/librte_eal/common/eal_common_thread.c | 38 +++++++++++++---------- > 1 file changed, 21 insertions(+), 17 deletions(-) > > diff --git a/lib/librte_eal/common/eal_common_thread.c b/lib/librte_eal/common/eal_common_thread.c > index 73a055902a..891f825e87 100644 > --- a/lib/librte_eal/common/eal_common_thread.c > +++ b/lib/librte_eal/common/eal_common_thread.c > @@ -170,11 +170,11 @@ struct rte_thread_ctrl_params { > void *(*start_routine)(void *); > void *arg; > pthread_barrier_t configured; > + unsigned int barrier_refcnt; > }; > > 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; > @@ -184,8 +184,9 @@ static void *ctrl_thread_init(void *arg) > > __rte_thread_init(rte_lcore_id(), cpuset); > > - ret = pthread_barrier_wait(¶ms->configured); > - if (ret == PTHREAD_BARRIER_SERIAL_THREAD) { > + pthread_barrier_wait(¶ms->configured); > + if (__atomic_sub_fetch(¶ms->barrier_refcnt, 1, > + __ATOMIC_ACQ_REL) == 0) { > pthread_barrier_destroy(¶ms->configured); > free(params); > } > @@ -210,15 +211,17 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name, > > params->start_routine = start_routine; > params->arg = arg; > - > - pthread_barrier_init(¶ms->configured, NULL, 2); > - > - ret = pthread_create(thread, attr, ctrl_thread_init, (void *)params); > + __atomic_store_n(¶ms->barrier_refcnt, 2, __ATOMIC_RELEASE); > + ret = pthread_barrier_init(¶ms->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 +230,26 @@ 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_wait(¶ms->configured); > + if (__atomic_sub_fetch(¶ms->barrier_refcnt, 1, > + __ATOMIC_ACQ_REL) == 0) { > pthread_barrier_destroy(¶ms->configured); > 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: > + pthread_barrier_destroy(¶ms->configured); > + free(params); > + > return -ret; > } > > -- > 2.29.2 >
next prev parent reply other threads:[~2021-03-25 14:42 UTC|newest] Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-03-24 13:04 [dpdk-dev] [PATCH] eal: fix possible UB on creation of ctrl thread Luc Pelletier 2021-03-25 11:27 ` [dpdk-dev] [PATCH v2] eal: fix race in ctrl thread creation Olivier Matz 2021-03-25 14:42 ` Luc Pelletier [this message] 2021-04-02 4:34 ` Honnappa Nagarahalli 2021-04-06 15:57 ` [dpdk-dev] [PATCH v3] eal: fix possible UB on creation of ctrl thread Luc Pelletier 2021-04-06 16:15 ` [dpdk-dev] [PATCH v3] eal: fix race in ctrl thread creation Luc Pelletier 2021-04-06 21:10 ` Honnappa Nagarahalli 2021-04-07 12:35 ` [dpdk-dev] [PATCH v4] " Luc Pelletier 2021-04-07 12:53 ` [dpdk-dev] [PATCH v5] " Luc Pelletier 2021-04-07 13:22 ` Luc Pelletier 2021-04-07 13:31 ` Olivier Matz 2021-04-07 14:42 ` [dpdk-dev] [PATCH v6] " Luc Pelletier 2021-04-07 14:57 ` Olivier Matz 2021-04-07 15:29 ` [dpdk-dev] [PATCH v7] " Luc Pelletier 2021-04-07 17:15 ` Honnappa Nagarahalli 2021-04-07 15:15 ` [dpdk-dev] [PATCH v5] " Honnappa Nagarahalli 2021-04-07 20:16 ` [dpdk-dev] [PATCH 1/2] " Luc Pelletier 2021-04-08 14:17 ` Olivier Matz 2021-04-08 17:06 ` Honnappa Nagarahalli 2021-04-07 20:16 ` [dpdk-dev] [PATCH 2/2] eal: fix hang in ctrl thread creation error logic Luc Pelletier 2021-04-08 14:20 ` Olivier Matz 2021-04-08 18:01 ` Luc Pelletier 2021-04-09 8:13 ` David Marchand 2021-04-08 17:07 ` Honnappa Nagarahalli 2021-04-09 14:34 ` [dpdk-dev] [dpdk-stable] " David Marchand
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