Re: [PATCH 1/5] workqueue: fix memory leak in wq_numa_init()

[Lai Jiangshan]

On 12/13/2014 01:12 AM, Tejun Heo wrote:
> On Fri, Dec 12, 2014 at 06:19:51PM +0800, Lai Jiangshan wrote:
>> wq_numa_init() will quit directly on some bonkers cases without freeing the
>> memory.  Add the missing cleanup code.
>>
>> Cc: Tejun Heo 
>> Cc: Yasuaki Ishimatsu 
>> Cc: "Gu, Zheng" 
>> Cc: tangchen 
>> Cc: Hiroyuki KAMEZAWA 
>> Signed-off-by: Lai Jiangshan 
>> ---
>>  kernel/workqueue.c |3 +++
>>  1 files changed, 3 insertions(+), 0 deletions(-)
>>
>> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
>> index 09b685d..a6fd2b8 100644
>> --- a/kernel/workqueue.c
>> +++ b/kernel/workqueue.c
>> @@ -4811,6 +4811,9 @@ static void __init wq_numa_init(void)
>>  if (WARN_ON(node == NUMA_NO_NODE)) {
>>  pr_warn("workqueue: NUMA node mapping not available for 
>> cpu%d, disabling NUMA support\n", cpu);
>>  /* happens iff arch is bonkers, let's just proceed */
>> +for_each_node(node)
>> +free_cpumask_var(tbl[node]);
>> +kfree(tbl);
> 
> The comment right up there says that this happens if and only if the
> arch code is seriously broken and it's consciously skipping exception
> handling.  That's a condition where we might as well trigger BUG_ON().
> Just leave it alone.


cpu_to_node() can return NUMA_NO_NODE after system booted (when node offline) 
currently.
so I don't think it is seriously broken if cpu_to_node() returns NUMA_NO_NODE
when booting.

See:

static void unmap_cpu_on_node(pg_data_t *pgdat)
{
#ifdef CONFIG_ACPI_NUMA
int cpu;

for_each_possible_cpu(cpu)
if (cpu_to_node(cpu) == pgdat->node_id)
numa_clear_node(cpu);
#endif
}

> 
> Thanks.
> 

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Re: [PATCH 1/5] workqueue: fix memory leak in wq_numa_init()

[Tejun Heo]

On Fri, Dec 12, 2014 at 06:19:51PM +0800, Lai Jiangshan wrote:
> wq_numa_init() will quit directly on some bonkers cases without freeing the
> memory.  Add the missing cleanup code.
> 
> Cc: Tejun Heo 
> Cc: Yasuaki Ishimatsu 
> Cc: "Gu, Zheng" 
> Cc: tangchen 
> Cc: Hiroyuki KAMEZAWA 
> Signed-off-by: Lai Jiangshan 
> ---
>  kernel/workqueue.c |3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index 09b685d..a6fd2b8 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -4811,6 +4811,9 @@ static void __init wq_numa_init(void)
>   if (WARN_ON(node == NUMA_NO_NODE)) {
>   pr_warn("workqueue: NUMA node mapping not available for 
> cpu%d, disabling NUMA support\n", cpu);
>   /* happens iff arch is bonkers, let's just proceed */
> + for_each_node(node)
> + free_cpumask_var(tbl[node]);
> + kfree(tbl);

The comment right up there says that this happens if and only if the
arch code is seriously broken and it's consciously skipping exception
handling.  That's a condition where we might as well trigger BUG_ON().
Just leave it alone.

Thanks.

-- 
tejun
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[PATCH 1/5] workqueue: fix memory leak in wq_numa_init()

[Lai Jiangshan]

wq_numa_init() will quit directly on some bonkers cases without freeing the
memory.  Add the missing cleanup code.

Cc: Tejun Heo 
Cc: Yasuaki Ishimatsu 
Cc: "Gu, Zheng" 
Cc: tangchen 
Cc: Hiroyuki KAMEZAWA 
Signed-off-by: Lai Jiangshan 
---
 kernel/workqueue.c |3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 09b685d..a6fd2b8 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -4811,6 +4811,9 @@ static void __init wq_numa_init(void)
if (WARN_ON(node == NUMA_NO_NODE)) {
pr_warn("workqueue: NUMA node mapping not available for 
cpu%d, disabling NUMA support\n", cpu);
/* happens iff arch is bonkers, let's just proceed */
+   for_each_node(node)
+   free_cpumask_var(tbl[node]);
+   kfree(tbl);
return;
}
cpumask_set_cpu(cpu, tbl[node]);
-- 
1.7.4.4

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