From: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com> To: Luc Pelletier <lucp.at.work@gmail.com>, "olivier.matz@6wind.com" <olivier.matz@6wind.com>, "jianfeng.tan@intel.com" <jianfeng.tan@intel.com> Cc: "dev@dpdk.org" <dev@dpdk.org>, "stable@dpdk.org" <stable@dpdk.org>, nd <nd@arm.com>, Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>, nd <nd@arm.com> Subject: Re: [dpdk-dev] [PATCH v3] eal: fix race in ctrl thread creation Date: Tue, 6 Apr 2021 21:10:48 +0000 Message-ID: <DBAPR08MB58141D42D9E6E276A66643BC98769@DBAPR08MB5814.eurprd08.prod.outlook.com> (raw) In-Reply-To: <20210406161534.103272-1-lucp.at.work@gmail.com> <snip> > > The creation of control threads used 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. > The barrier has been completely removed in favour of a reference count on > the control thread parameters struct. > > Fixes: 3a0d465d4c53 ("eal: fix use-after-free on control thread creation") > Cc: jianfeng.tan@intel.com > Cc: stable@dpdk.org > > Signed-off-by: Luc Pelletier <lucp.at.work@gmail.com> > --- > > Hi Olivier, > Hi Honnappa, > > Thanks for your input Honnappa. I've made the changes to completely > remove the barrier. However, I didn't move the call to pthread_setaffinity_np I looked at the rte_ctrl_thread_create API definition. I am not sure if we have much leavy here as the API definition bakes in calling pthread_setaffinity_np. With the barrier, the control thread did not execute its function till it was moved to the assigned core. If we remove the barrier and not move the pthread_setaffinity_np to ctrl_thread_init, the behavior might change. One more comment below on how we are handling the setaffinity failure. > to the control thread; I think we want to report the result of that function to > the caller of rte_ctrl_thread_create and doing so from ctrl_thread_init would > be a lot trickier. > > Olivier, what do you think of these changes? > > lib/librte_eal/common/eal_common_thread.c | 35 ++++++++--------------- > 1 file changed, 12 insertions(+), 23 deletions(-) > > diff --git a/lib/librte_eal/common/eal_common_thread.c > b/lib/librte_eal/common/eal_common_thread.c > index 73a055902..2421066f9 100644 > --- a/lib/librte_eal/common/eal_common_thread.c > +++ b/lib/librte_eal/common/eal_common_thread.c > @@ -169,12 +169,11 @@ __rte_thread_uninit(void) struct > rte_thread_ctrl_params { > void *(*start_routine)(void *); > void *arg; > - pthread_barrier_t configured; > + unsigned int 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; @@ -184,11 > +183,8 @@ 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_destroy(¶ms->configured); > + if (__atomic_sub_fetch(¶ms->refcnt, 1, __ATOMIC_ACQ_REL) == > 0) > free(params); > - } > > return start_routine(routine_arg); > } > @@ -210,14 +206,11 @@ 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); > + params->refcnt = 2; > > ret = pthread_create(thread, attr, ctrl_thread_init, (void *)params); > - if (ret != 0) { > - free(params); > - return -ret; > - } > + if (ret != 0) > + goto fail; > > if (name != NULL) { > ret = rte_thread_setname(*thread, name); @@ -228,24 > +221,20 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name, > > ret = pthread_setaffinity_np(*thread, sizeof(*cpuset), cpuset); > if (ret) > - goto fail; > + goto fail_cancel; > > - ret = pthread_barrier_wait(¶ms->configured); > - if (ret == PTHREAD_BARRIER_SERIAL_THREAD) { > - pthread_barrier_destroy(¶ms->configured); > + if (__atomic_sub_fetch(¶ms->refcnt, 1, __ATOMIC_ACQ_REL) == > 0) > 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); For the control thread to be able to respond to pthread_cancel, it needs to call one of the library functions that is considered a cancellation point. I do not see such requirements in the API definition. > pthread_join(*thread, NULL); > + > +fail: > + free(params); > + > return -ret; > } > > -- > 2.25.1
next prev parent reply other threads:[~2021-04-06 21:11 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 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 [this message] 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
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=DBAPR08MB58141D42D9E6E276A66643BC98769@DBAPR08MB5814.eurprd08.prod.outlook.com \ --to=honnappa.nagarahalli@arm.com \ --cc=dev@dpdk.org \ --cc=jianfeng.tan@intel.com \ --cc=lucp.at.work@gmail.com \ --cc=nd@arm.com \ --cc=olivier.matz@6wind.com \ --cc=stable@dpdk.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
DPDK patches and discussions This inbox may be cloned and mirrored by anyone: git clone --mirror https://inbox.dpdk.org/dev/0 dev/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 dev dev/ https://inbox.dpdk.org/dev \ dev@dpdk.org public-inbox-index dev Example config snippet for mirrors. Newsgroup available over NNTP: nntp://inbox.dpdk.org/inbox.dpdk.dev AGPL code for this site: git clone https://public-inbox.org/public-inbox.git