From: Christian Ehrhardt <christian.ehrhardt@canonical.com>
To: Luc Pelletier <lucp.at.work@gmail.com>
Cc: dpdk stable <stable@dpdk.org>
Subject: Re: [dpdk-stable] [PATCH 19.11.9 2/2] eal: fix hang in control thread creation
Date: Thu, 3 Jun 2021 07:00:08 +0200 [thread overview]
Message-ID: <CAATJJ0J+omHa7hEKV7kWv0ep3fWNieKQ9b7GZFMrNwA3gPHOfQ@mail.gmail.com> (raw)
In-Reply-To: <20210521154907.320565-2-lucp.at.work@gmail.com>
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
next prev parent reply other threads:[~2021-06-03 5:00 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-21 15:49 [dpdk-stable] [PATCH 19.11.9 1/2] eal: fix race " 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 [this message]
2021-06-03 4:59 ` [dpdk-stable] [PATCH 19.11.9 1/2] eal: fix race " Christian Ehrhardt
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=CAATJJ0J+omHa7hEKV7kWv0ep3fWNieKQ9b7GZFMrNwA3gPHOfQ@mail.gmail.com \
--to=christian.ehrhardt@canonical.com \
--cc=lucp.at.work@gmail.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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).