From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 00EC5A0A02; Thu, 25 Mar 2021 15:42:50 +0100 (CET) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 6C635140DAF; Thu, 25 Mar 2021 15:42:50 +0100 (CET) Received: from mail-lj1-f177.google.com (mail-lj1-f177.google.com [209.85.208.177]) by mails.dpdk.org (Postfix) with ESMTP id CA7DE4067B; Thu, 25 Mar 2021 15:42:49 +0100 (CET) Received: by mail-lj1-f177.google.com with SMTP id f26so3428367ljp.8; Thu, 25 Mar 2021 07:42:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=Br90KYVN5VoHoRMbAKPIbUnU2thqGVhKeL1gmUFhXoI=; b=j5JqUDuvOV9r8OkP5x8HBYfqvUp/0OBakkjL4oGfLOgg9fue/qE7cUV7SrTqNQZWpi EFUm8pmAotk01H+3B/7Aa1muEUgiZyfdd+gZ2FoH9UkvfHGvEzqoXkUCbWu7y2462RNd EVPqqiv67UJZBlXi8YNjJRjye+Em9i+HS4BCokH+9fe/8OniOGzGTZ3lbOpCwo+xm7wS 5g392/IMwSgg1zJgvQqQcD2g2U/K/JnkWdrxKi1vkUc97PvKngl2SNyAGeaL8EyGCcAC 2lyxp4bS4niwh/WJkmenHYj+ItBmHiR6vbjMrO6xcGNZfcAqVP78vIpCUTt92Iit4ujT pkFg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=Br90KYVN5VoHoRMbAKPIbUnU2thqGVhKeL1gmUFhXoI=; b=FvalV8Gz5kYpCxR6MYJiIdzh/ijPTlLHEjnZlvkP3pI0ZO0hqSZ9KvXDLVCAA16CBX xAezWDT5mzfzYnD/6yOkvEoQ0W/6UldjJMW/0uf57bm0hBnhLXvCqMf5mHAXoltVmQd2 4SCLcfVbTsf9EPyPl2IZK8Wmc/ESkqFm9GPkCqhI98ys1+dMiBwTrrt4YEMKo9pr0tw7 vWmCHYcMvsQiE4AUmlj7HZoZIOf7yZDCAWg553CrbWLiF0dzbyvkqN6/bPgAMFdwizr6 bqGwGU7ySKAQ/WHy/GsuUoljAQt66hkdPjfGtMThYrb9C/FagPttw8SH0xR3WcEUGELi E3sg== X-Gm-Message-State: AOAM5327QgRaktz+OFFWRW6qeNdEoy3uhhHTho78clkbpSVsns4ULLxV ZJ9XeGXp2/AsBZu7BS0hTlM4CucihQsY52pDtOc= X-Google-Smtp-Source: ABdhPJz9gcC/2VPsZ6RkkysS0e1fPTVjSvvWk+EbeTdFxK895e8B3pPC34GfmgA0Y/D8bwJVYyAqUnt3seP9eIp6i7w= X-Received: by 2002:a2e:b4d0:: with SMTP id r16mr5846913ljm.324.1616683369404; Thu, 25 Mar 2021 07:42:49 -0700 (PDT) MIME-Version: 1.0 References: <20210324130422.92357-1-lucp.at.work@gmail.com> <20210325112731.16324-1-olivier.matz@6wind.com> In-Reply-To: <20210325112731.16324-1-olivier.matz@6wind.com> From: Luc Pelletier Date: Thu, 25 Mar 2021 10:42:38 -0400 Message-ID: To: Olivier Matz Cc: dev@dpdk.org, jianfeng.tan@intel.com, david.marchand@redhat.com, stable@dpdk.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [dpdk-dev] [PATCH v2] eal: fix race in ctrl thread creation X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" 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 =C3=A0 07:27, Olivier Matz a = =C3=A9crit : > > 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 > Signed-off-by: David Marchand > Signed-off-by: Olivier Matz > --- > > 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/c= ommon/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 =3D > eal_get_internal_configuration(); > rte_cpuset_t *cpuset =3D &internal_conf->ctrl_cpuset; > @@ -184,8 +184,9 @@ static void *ctrl_thread_init(void *arg) > > __rte_thread_init(rte_lcore_id(), cpuset); > > - ret =3D pthread_barrier_wait(¶ms->configured); > - if (ret =3D=3D PTHREAD_BARRIER_SERIAL_THREAD) { > + pthread_barrier_wait(¶ms->configured); > + if (__atomic_sub_fetch(¶ms->barrier_refcnt, 1, > + __ATOMIC_ACQ_REL) =3D=3D 0) { > pthread_barrier_destroy(¶ms->configured); > free(params); > } > @@ -210,15 +211,17 @@ rte_ctrl_thread_create(pthread_t *thread, const cha= r *name, > > params->start_routine =3D start_routine; > params->arg =3D arg; > - > - pthread_barrier_init(¶ms->configured, NULL, 2); > - > - ret =3D pthread_create(thread, attr, ctrl_thread_init, (void *)pa= rams); > + __atomic_store_n(¶ms->barrier_refcnt, 2, __ATOMIC_RELEASE); > + ret =3D pthread_barrier_init(¶ms->configured, NULL, 2); > if (ret !=3D 0) { > free(params); > return -ret; > } > > + ret =3D pthread_create(thread, attr, ctrl_thread_init, (void *)pa= rams); > + if (ret !=3D 0) > + goto fail; > + > if (name !=3D NULL) { > ret =3D rte_thread_setname(*thread, name); > if (ret < 0) > @@ -227,25 +230,26 @@ rte_ctrl_thread_create(pthread_t *thread, const cha= r *name, > } > > ret =3D pthread_setaffinity_np(*thread, sizeof(*cpuset), cpuset); > - if (ret) > - goto fail; > + if (ret !=3D 0) > + goto fail_cancel; > > - ret =3D pthread_barrier_wait(¶ms->configured); > - if (ret =3D=3D PTHREAD_BARRIER_SERIAL_THREAD) { > + pthread_barrier_wait(¶ms->configured); > + if (__atomic_sub_fetch(¶ms->barrier_refcnt, 1, > + __ATOMIC_ACQ_REL) =3D=3D 0) { > pthread_barrier_destroy(¶ms->configured); > free(params); > } > > return 0; > > -fail: > - if (PTHREAD_BARRIER_SERIAL_THREAD =3D=3D > - 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 >