From: "Burakov, Anatoly" <anatoly.burakov@intel.com>
To: Erik Gabriel Carrillo <erik.g.carrillo@intel.com>,
rsanford@akamai.com, thomas@monjalon.net
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH v2] timer: fix resource leak in finalize
Date: Tue, 7 May 2019 12:03:40 +0100 [thread overview]
Message-ID: <7baed0b9-432f-be86-5e39-68035bc309a4@intel.com> (raw)
Message-ID: <20190507110340.pL97gWyfy-3EAEuXBE2Ivk3Om0u20KVnC5qM3qwhMCk@z> (raw)
In-Reply-To: <1556924082-22535-1-git-send-email-erik.g.carrillo@intel.com>
On 03-May-19 11:54 PM, Erik Gabriel Carrillo wrote:
> The finalize function should free the memzone created in the init
> function, rather than freeing the allocation the memzone references,
> otherwise a memzone descriptor can be leaked.
>
> Fixes: c0749f7096c7 ("timer: allow management in shared memory")
>
> Signed-off-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com>
> ---
> changes in v2:
> - Handle scenario where primary process exits before secondaries such
> that memzone is not freed early (Anatoly)
>
> lib/librte_timer/rte_timer.c | 20 +++++++++++++++++---
> 1 file changed, 17 insertions(+), 3 deletions(-)
>
> diff --git a/lib/librte_timer/rte_timer.c b/lib/librte_timer/rte_timer.c
> index eb46009..4771287 100644
> --- a/lib/librte_timer/rte_timer.c
> +++ b/lib/librte_timer/rte_timer.c
> @@ -60,6 +60,8 @@ struct rte_timer_data {
> };
>
> #define RTE_MAX_DATA_ELS 64
> +static const struct rte_memzone *rte_timer_data_mz;
> +static rte_atomic16_t *rte_timer_mz_refcnt;
> static struct rte_timer_data *rte_timer_data_arr;
> static const uint32_t default_data_id;
> static uint32_t rte_timer_subsystem_initialized;
> @@ -155,6 +157,7 @@ rte_timer_subsystem_init_v1905(void)
> struct rte_timer_data *data;
> int i, lcore_id;
> static const char *mz_name = "rte_timer_mz";
> + size_t data_arr_size = RTE_MAX_DATA_ELS * sizeof(*rte_timer_data_arr);
nitpicking, but... const?
>
> if (rte_timer_subsystem_initialized)
> return -EALREADY;
> @@ -164,10 +167,14 @@ rte_timer_subsystem_init_v1905(void)
> if (mz == NULL)
> return -EEXIST;
>
> + rte_timer_data_mz = mz;
> rte_timer_data_arr = mz->addr;
> + rte_timer_mz_refcnt =
> + (void *)((char *)mz->addr + data_arr_size);
>
> rte_timer_data_arr[default_data_id].internal_flags |=
> FL_ALLOCATED;
> + rte_atomic16_inc(rte_timer_mz_refcnt);
>
> rte_timer_subsystem_initialized = 1;
>
> @@ -175,12 +182,15 @@ rte_timer_subsystem_init_v1905(void)
> }
>
> mz = rte_memzone_reserve_aligned(mz_name,
> - RTE_MAX_DATA_ELS * sizeof(*rte_timer_data_arr),
> + data_arr_size + sizeof(*rte_timer_mz_refcnt),
> SOCKET_ID_ANY, 0, RTE_CACHE_LINE_SIZE);
> if (mz == NULL)
> return -ENOMEM;
>
> + rte_timer_data_mz = mz;
> rte_timer_data_arr = mz->addr;
> + rte_timer_mz_refcnt = (void *)((char *)mz->addr + data_arr_size);
> + rte_atomic16_init(rte_timer_mz_refcnt);
>
> for (i = 0; i < RTE_MAX_DATA_ELS; i++) {
> data = &rte_timer_data_arr[i];
> @@ -193,6 +203,7 @@ rte_timer_subsystem_init_v1905(void)
> }
>
> rte_timer_data_arr[default_data_id].internal_flags |= FL_ALLOCATED;
> + rte_atomic16_inc(rte_timer_mz_refcnt);
>
> rte_timer_subsystem_initialized = 1;
>
> @@ -205,8 +216,11 @@ BIND_DEFAULT_SYMBOL(rte_timer_subsystem_init, _v1905, 19.05);
> void __rte_experimental
> rte_timer_subsystem_finalize(void)
> {
> - if (rte_timer_data_arr)
> - rte_free(rte_timer_data_arr);
> + if (!rte_timer_subsystem_initialized)
> + return;
> +
> + if (rte_atomic16_dec_and_test(rte_timer_mz_refcnt))
> + rte_memzone_free(rte_timer_data_mz);
I think there's a race here. You may get preempted after test but before
free, where another secondary could initialize. As far as i know, we
also support a case when secondary initializes after primary stops running.
Let's even suppose that we allow secondary processes to initialize the
timer subsystem by reserving memzone and checking rte_errno. You would
still have a chance of two init/deinit conflicting, because there's a
hole between memzone allocation and atomic increment.
I don't think this race can be resolved in a safe way, so we might just
have to settle for a memory leak.
>
> rte_timer_subsystem_initialized = 0;
> }
>
--
Thanks,
Anatoly
next prev parent reply other threads:[~2019-05-07 11:03 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-01 19:00 [dpdk-dev] [PATCH] " Erik Gabriel Carrillo
2019-05-01 19:00 ` Erik Gabriel Carrillo
2019-05-02 9:18 ` Burakov, Anatoly
2019-05-02 9:18 ` Burakov, Anatoly
2019-05-02 12:19 ` Carrillo, Erik G
2019-05-02 12:19 ` Carrillo, Erik G
2019-05-02 13:03 ` Burakov, Anatoly
2019-05-02 13:03 ` Burakov, Anatoly
2019-05-02 13:48 ` Carrillo, Erik G
2019-05-02 13:48 ` Carrillo, Erik G
2019-05-03 22:54 ` [dpdk-dev] [PATCH v2] " Erik Gabriel Carrillo
2019-05-03 22:54 ` Erik Gabriel Carrillo
2019-05-07 11:03 ` Burakov, Anatoly [this message]
2019-05-07 11:03 ` Burakov, Anatoly
2019-05-07 22:04 ` Carrillo, Erik G
2019-05-07 22:04 ` Carrillo, Erik G
2019-05-08 8:49 ` Burakov, Anatoly
2019-05-08 8:49 ` Burakov, Anatoly
2019-05-08 23:01 ` Carrillo, Erik G
2019-05-08 23:01 ` Carrillo, Erik G
2019-05-09 7:44 ` Thomas Monjalon
2019-05-09 7:44 ` Thomas Monjalon
2019-05-08 22:35 ` [dpdk-dev] [PATCH v3] " Erik Gabriel Carrillo
2019-05-08 22:35 ` Erik Gabriel Carrillo
2019-05-09 8:29 ` Burakov, Anatoly
2019-05-09 8:29 ` Burakov, Anatoly
2019-06-05 9:33 ` Thomas Monjalon
2019-06-05 9:47 ` Burakov, Anatoly
2019-06-25 16:11 ` [dpdk-dev] [PATCH 0/2] Fix timer resource leak Anatoly Burakov
2019-07-05 13:20 ` [dpdk-dev] [PATCH v2 0/1] " Anatoly Burakov
2019-07-05 17:22 ` [dpdk-dev] [PATCH v3 " Anatoly Burakov
2019-07-05 17:22 ` [dpdk-dev] [PATCH v3 1/1] timer: fix resource leak in finalize Anatoly Burakov
2019-07-05 22:06 ` Thomas Monjalon
2019-07-05 13:20 ` [dpdk-dev] [PATCH v2 " Anatoly Burakov
2019-06-25 16:11 ` [dpdk-dev] [PATCH 1/2] eal: add internal locks for timer lib into EAL Anatoly Burakov
2019-06-27 18:41 ` Carrillo, Erik G
2019-07-04 9:09 ` David Marchand
2019-07-04 10:44 ` Burakov, Anatoly
2019-06-25 16:11 ` [dpdk-dev] [PATCH 2/2] timer: fix resource leak in finalize Anatoly Burakov
2019-06-27 18:48 ` Carrillo, Erik G
2019-07-04 9:10 ` David Marchand
2019-07-04 10:45 ` Burakov, Anatoly
2019-07-04 10:50 ` 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=7baed0b9-432f-be86-5e39-68035bc309a4@intel.com \
--to=anatoly.burakov@intel.com \
--cc=dev@dpdk.org \
--cc=erik.g.carrillo@intel.com \
--cc=rsanford@akamai.com \
--cc=thomas@monjalon.net \
/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).