[dpdk-dev] [PATCH] timer: fix resource leak in finalize
Burakov, Anatoly
anatoly.burakov at intel.com
Thu May 2 15:03:42 CEST 2019
On 02-May-19 1:19 PM, Carrillo, Erik G wrote:
>
>
>> -----Original Message-----
>> From: Burakov, Anatoly
>> Sent: Thursday, May 2, 2019 4:18 AM
>> To: Carrillo, Erik G <erik.g.carrillo at intel.com>; rsanford at akamai.com;
>> thomas at monjalon.net
>> Cc: dev at dpdk.org
>> Subject: Re: [dpdk-dev] [PATCH] timer: fix resource leak in finalize
>>
>> On 01-May-19 8:00 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 at intel.com>
>>> ---
>>> lib/librte_timer/rte_timer.c | 12 ++++++++++--
>>> 1 file changed, 10 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/lib/librte_timer/rte_timer.c
>>> b/lib/librte_timer/rte_timer.c index eb46009..fb7a87e 100644
>>> --- a/lib/librte_timer/rte_timer.c
>>> +++ b/lib/librte_timer/rte_timer.c
>>> @@ -60,6 +60,7 @@ struct rte_timer_data {
>>> };
>>>
>>> #define RTE_MAX_DATA_ELS 64
>>> +static const struct rte_memzone *rte_timer_data_mz;
>>> static struct rte_timer_data *rte_timer_data_arr;
>>> static const uint32_t default_data_id;
>>> static uint32_t rte_timer_subsystem_initialized; @@ -164,6 +165,7 @@
>>> rte_timer_subsystem_init_v1905(void)
>>> if (mz == NULL)
>>> return -EEXIST;
>>>
>>> + rte_timer_data_mz = mz;
>>> rte_timer_data_arr = mz->addr;
>>>
>>> rte_timer_data_arr[default_data_id].internal_flags |= @@ -
>> 180,6
>>> +182,7 @@ rte_timer_subsystem_init_v1905(void)
>>> if (mz == NULL)
>>> return -ENOMEM;
>>>
>>> + rte_timer_data_mz = mz;
>>> rte_timer_data_arr = mz->addr;
>>>
>>> for (i = 0; i < RTE_MAX_DATA_ELS; i++) { @@ -205,8 +208,13 @@
>>> 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_eal_process_type() != RTE_PROC_PRIMARY)
>>> + return;
>>> +
>>> + if (!rte_timer_subsystem_initialized)
>>> + return;
>>> +
>>> + rte_memzone_free(rte_timer_data_mz);
>>
>> The patch is a correct fix, but the whole idea of this looks dangerous to me.
>>
>> If we exit the primary while secondaries are still running, wouldn't it basically
>> pull out timer data from under secondaries' feet?
>>
>
> Ah yes - that’s right. Perhaps it would be better to maintain a reference count of some sort such that the last process to exit could cause the memzone_free.
>
It feels like a hack, to be honest. A process can crash or exit without
calling rte_eal_cleanup(), which will lead to a memory leak due to
refcount being stuck at a value that's not representing reality. It will
be saf-er than current approach, but still not ideal.
However, i guess it's a good compromise, if i were to choose between a
memory leak and a segfault :D I wonder if there is a better approach.
> Thanks,
> Erik
>
>>>
>>> rte_timer_subsystem_initialized = 0;
>>> }
>>>
>>
>>
>> --
>> Thanks,
>> Anatoly
--
Thanks,
Anatoly
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