2021-07-19 07:01:40

by Zhen Lei

Subject: [PATCH] workqueue: Fix possible memory leaks in wq_numa_init()

In error handling branch "if (WARN_ON(node == NUMA_NO_NODE))", the
previously allocated memories are not released. Doing this before
allocating memory eliminates memory leaks.

Signed-off-by: Zhen Lei <[email protected]>
---
kernel/workqueue.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 50142fc08902..6aa0ba582d15 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -5896,6 +5896,14 @@ static void __init wq_numa_init(void)
return;
}

+ for_each_possible_cpu(cpu) {
+ if (WARN_ON(cpu_to_node(cpu) == 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 */
+ return;
+ }
+ }
+
wq_update_unbound_numa_attrs_buf = alloc_workqueue_attrs();
BUG_ON(!wq_update_unbound_numa_attrs_buf);

@@ -5907,18 +5915,11 @@ static void __init wq_numa_init(void)
tbl = kcalloc(nr_node_ids, sizeof(tbl[0]), GFP_KERNEL);
BUG_ON(!tbl);

- for_each_node(node)
+ for_each_node(node) {
BUG_ON(!zalloc_cpumask_var_node(&tbl[node], GFP_KERNEL,
node_online(node) ? node : NUMA_NO_NODE));

- for_each_possible_cpu(cpu) {
- node = cpu_to_node(cpu);
- 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 */
- return;
- }
- cpumask_set_cpu(cpu, tbl[node]);
+ cpumask_copy(tbl[node], cpumask_of_node(node));
}

wq_numa_possible_cpumask = tbl;
--
2.25.1

2021-07-19 09:00:57

by Lai Jiangshan

Subject: Re: [PATCH] workqueue: Fix possible memory leaks in wq_numa_init()

Hello, Tejun

I think it would be better to fix it.
There have been several tries, sorted by date:

https://lore.kernel.org/lkml/[email protected]/
https://lore.kernel.org/lkml/[email protected]/
https://lore.kernel.org/lkml/[email protected]/
https://lore.kernel.org/lkml/[email protected]/

And this one.

Thanks
Lai


On Mon, Jul 19, 2021 at 3:00 PM Zhen Lei <[email protected]> wrote:
>
> In error handling branch "if (WARN_ON(node == NUMA_NO_NODE))", the
> previously allocated memories are not released. Doing this before
> allocating memory eliminates memory leaks.
>
> Signed-off-by: Zhen Lei <[email protected]>
> ---
> kernel/workqueue.c | 19 ++++++++++---------
> 1 file changed, 10 insertions(+), 9 deletions(-)
>
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index 50142fc08902..6aa0ba582d15 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -5896,6 +5896,14 @@ static void __init wq_numa_init(void)
> return;
> }
>
> + for_each_possible_cpu(cpu) {
> + if (WARN_ON(cpu_to_node(cpu) == 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 */
> + return;
> + }
> + }
> +
> wq_update_unbound_numa_attrs_buf = alloc_workqueue_attrs();
> BUG_ON(!wq_update_unbound_numa_attrs_buf);
>
> @@ -5907,18 +5915,11 @@ static void __init wq_numa_init(void)
> tbl = kcalloc(nr_node_ids, sizeof(tbl[0]), GFP_KERNEL);
> BUG_ON(!tbl);
>
> - for_each_node(node)
> + for_each_node(node) {
> BUG_ON(!zalloc_cpumask_var_node(&tbl[node], GFP_KERNEL,
> node_online(node) ? node : NUMA_NO_NODE));
>
> - for_each_possible_cpu(cpu) {
> - node = cpu_to_node(cpu);
> - 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 */
> - return;
> - }
> - cpumask_set_cpu(cpu, tbl[node]);
> + cpumask_copy(tbl[node], cpumask_of_node(node));
> }
>
> wq_numa_possible_cpumask = tbl;
> --
> 2.25.1
>

2021-07-21 21:04:07

by Tejun Heo

Subject: Re: [PATCH] workqueue: Fix possible memory leaks in wq_numa_init()

On Mon, Jul 19, 2021 at 04:49:05PM +0800, Lai Jiangshan wrote:
> Hello, Tejun
>
> I think it would be better to fix it.
> There have been several tries, sorted by date:
>
> https://lore.kernel.org/lkml/[email protected]/
> https://lore.kernel.org/lkml/[email protected]/
> https://lore.kernel.org/lkml/[email protected]/
> https://lore.kernel.org/lkml/[email protected]/
>
> And this one.

Yeah, idk. It's not an actual bug tho. Maybe we should just add a comment.
Which version do you like the best?

Thanks.

--
tejun

2021-07-22 01:56:56

by Lai Jiangshan

Subject: Re: [PATCH] workqueue: Fix possible memory leaks in wq_numa_init()

On Mon, Jul 19, 2021 at 3:00 PM Zhen Lei <[email protected]> wrote:
>
> In error handling branch "if (WARN_ON(node == NUMA_NO_NODE))", the
> previously allocated memories are not released. Doing this before
> allocating memory eliminates memory leaks.
>
> Signed-off-by: Zhen Lei <[email protected]>
> ---
> kernel/workqueue.c | 19 ++++++++++---------
> 1 file changed, 10 insertions(+), 9 deletions(-)
>
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index 50142fc08902..6aa0ba582d15 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -5896,6 +5896,14 @@ static void __init wq_numa_init(void)
> return;
> }
>
> + for_each_possible_cpu(cpu) {
> + if (WARN_ON(cpu_to_node(cpu) == 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 */
> + return;
> + }
> + }
> +
> wq_update_unbound_numa_attrs_buf = alloc_workqueue_attrs();
> BUG_ON(!wq_update_unbound_numa_attrs_buf);
>
> @@ -5907,18 +5915,11 @@ static void __init wq_numa_init(void)
> tbl = kcalloc(nr_node_ids, sizeof(tbl[0]), GFP_KERNEL);
> BUG_ON(!tbl);
>
> - for_each_node(node)
> + for_each_node(node) {
> BUG_ON(!zalloc_cpumask_var_node(&tbl[node], GFP_KERNEL,
> node_online(node) ? node : NUMA_NO_NODE));
>
> - for_each_possible_cpu(cpu) {
> - node = cpu_to_node(cpu);
> - 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 */
> - return;
> - }
> - cpumask_set_cpu(cpu, tbl[node]);
> + cpumask_copy(tbl[node], cpumask_of_node(node));

It is incorrect. cpumask_of_node(node) is the online cpumask of the node, not
the possible cpumask of the node that we are interested in.

If the NUMA subsystem provided something like cpumask_possible_of_node(node),
we wouldn't need wq_numa_possible_cpumask.

Please keep "cpumask_copy(tbl[node], cpumask_of_node(node));" as before.

> }
>
> wq_numa_possible_cpumask = tbl;
> --
> 2.25.1
>

2021-07-22 02:09:01

by Lai Jiangshan

Subject: Re: [PATCH] workqueue: Fix possible memory leaks in wq_numa_init()

Please ignore my previous email which included/copied a wrong line of code.

On Thu, Jul 22, 2021 at 12:23 AM Tejun Heo <[email protected]> wrote:
> Yeah, idk. It's not an actual bug tho. Maybe we should just add a comment.
> Which version do you like the best?

I hope Zhen Lei continues to refine his version. I think he is still
working on it.

On Mon, Jul 19, 2021 at 3:00 PM Zhen Lei <[email protected]> wrote:
>
> In error handling branch "if (WARN_ON(node == NUMA_NO_NODE))", the
> previously allocated memories are not released. Doing this before
> allocating memory eliminates memory leaks.
>
> Signed-off-by: Zhen Lei <[email protected]>
> ---
> kernel/workqueue.c | 19 ++++++++++---------
> 1 file changed, 10 insertions(+), 9 deletions(-)
>
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index 50142fc08902..6aa0ba582d15 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -5896,6 +5896,14 @@ static void __init wq_numa_init(void)
> return;
> }
>
> + for_each_possible_cpu(cpu) {
> + if (WARN_ON(cpu_to_node(cpu) == 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 */

I don't think this comment is still needed.

> + return;
> + }
> + }
> +
> wq_update_unbound_numa_attrs_buf = alloc_workqueue_attrs();
> BUG_ON(!wq_update_unbound_numa_attrs_buf);
>
> @@ -5907,18 +5915,11 @@ static void __init wq_numa_init(void)
> tbl = kcalloc(nr_node_ids, sizeof(tbl[0]), GFP_KERNEL);
> BUG_ON(!tbl);
>
> - for_each_node(node)
> + for_each_node(node) {
> BUG_ON(!zalloc_cpumask_var_node(&tbl[node], GFP_KERNEL,
> node_online(node) ? node : NUMA_NO_NODE));
>
> - for_each_possible_cpu(cpu) {
> - node = cpu_to_node(cpu);
> - 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 */
> - return;
> - }
> - cpumask_set_cpu(cpu, tbl[node]);
> + cpumask_copy(tbl[node], cpumask_of_node(node));

It is incorrect. cpumask_of_node(node) is the online cpumask of the node, not
the possible cpumask of the node that we are interested in.

If the NUMA subsystem provided something like cpumask_possible_of_node(node),
we wouldn't need wq_numa_possible_cpumask.

Please keep "for_each_possible_cpu(cpu)" loop and
"cpumask_set_cpu(cpu, tbl[node]);"

> }
>
> wq_numa_possible_cpumask = tbl;
> --
> 2.25.1
>

2021-07-22 02:39:46

by Zhen Lei

Subject: Re: [PATCH] workqueue: Fix possible memory leaks in wq_numa_init()

On 2021/7/22 9:55, Lai Jiangshan wrote:
> On Mon, Jul 19, 2021 at 3:00 PM Zhen Lei <[email protected]> wrote:
>>
>> In error handling branch "if (WARN_ON(node == NUMA_NO_NODE))", the
>> previously allocated memories are not released. Doing this before
>> allocating memory eliminates memory leaks.
>>
>> Signed-off-by: Zhen Lei <[email protected]>
>> ---
>> kernel/workqueue.c | 19 ++++++++++---------
>> 1 file changed, 10 insertions(+), 9 deletions(-)
>>
>> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
>> index 50142fc08902..6aa0ba582d15 100644
>> --- a/kernel/workqueue.c
>> +++ b/kernel/workqueue.c
>> @@ -5896,6 +5896,14 @@ static void __init wq_numa_init(void)
>> return;
>> }
>>
>> + for_each_possible_cpu(cpu) {
>> + if (WARN_ON(cpu_to_node(cpu) == 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 */
>> + return;
>> + }
>> + }
>> +
>> wq_update_unbound_numa_attrs_buf = alloc_workqueue_attrs();
>> BUG_ON(!wq_update_unbound_numa_attrs_buf);
>>
>> @@ -5907,18 +5915,11 @@ static void __init wq_numa_init(void)
>> tbl = kcalloc(nr_node_ids, sizeof(tbl[0]), GFP_KERNEL);
>> BUG_ON(!tbl);
>>
>> - for_each_node(node)
>> + for_each_node(node) {
>> BUG_ON(!zalloc_cpumask_var_node(&tbl[node], GFP_KERNEL,
>> node_online(node) ? node : NUMA_NO_NODE));
>>
>> - for_each_possible_cpu(cpu) {
>> - node = cpu_to_node(cpu);
>> - 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 */
>> - return;
>> - }
>> - cpumask_set_cpu(cpu, tbl[node]);
>> + cpumask_copy(tbl[node], cpumask_of_node(node));
>
> It is incorrect. cpumask_of_node(node) is the online cpumask of the node, not
> the possible cpumask of the node that we are interested in.
>
> If the NUMA subsystem provided something like cpumask_possible_of_node(node),
> we wouldn't need wq_numa_possible_cpumask.
>
> Please keep "cpumask_copy(tbl[node], cpumask_of_node(node));" as before.

OK，thanks.

>
>> }
>>
>> wq_numa_possible_cpumask = tbl;
>> --
>> 2.25.1
>>
> .
>

2021-07-22 02:47:22

by Zhen Lei

Subject: Re: [PATCH] workqueue: Fix possible memory leaks in wq_numa_init()

On 2021/7/22 10:05, Lai Jiangshan wrote:
> Please ignore my previous email which included/copied a wrong line of code.
>
> On Thu, Jul 22, 2021 at 12:23 AM Tejun Heo <[email protected]> wrote:
>> Yeah, idk. It's not an actual bug tho. Maybe we should just add a comment.
>> Which version do you like the best?
>
> I hope Zhen Lei continues to refine his version. I think he is still
> working on it.

Yes, I'm inclined to fix it, too. The tools aren't that smart, and handling
false positives is an annoyance.


>
> On Mon, Jul 19, 2021 at 3:00 PM Zhen Lei <[email protected]> wrote:
>>
>> In error handling branch "if (WARN_ON(node == NUMA_NO_NODE))", the
>> previously allocated memories are not released. Doing this before
>> allocating memory eliminates memory leaks.
>>
>> Signed-off-by: Zhen Lei <[email protected]>
>> ---
>> kernel/workqueue.c | 19 ++++++++++---------
>> 1 file changed, 10 insertions(+), 9 deletions(-)
>>
>> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
>> index 50142fc08902..6aa0ba582d15 100644
>> --- a/kernel/workqueue.c
>> +++ b/kernel/workqueue.c
>> @@ -5896,6 +5896,14 @@ static void __init wq_numa_init(void)
>> return;
>> }
>>
>> + for_each_possible_cpu(cpu) {
>> + if (WARN_ON(cpu_to_node(cpu) == 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 */
>
> I don't think this comment is still needed.

OK, I will remove it.

>
>> + return;
>> + }
>> + }
>> +
>> wq_update_unbound_numa_attrs_buf = alloc_workqueue_attrs();
>> BUG_ON(!wq_update_unbound_numa_attrs_buf);
>>
>> @@ -5907,18 +5915,11 @@ static void __init wq_numa_init(void)
>> tbl = kcalloc(nr_node_ids, sizeof(tbl[0]), GFP_KERNEL);
>> BUG_ON(!tbl);
>>
>> - for_each_node(node)
>> + for_each_node(node) {
>> BUG_ON(!zalloc_cpumask_var_node(&tbl[node], GFP_KERNEL,
>> node_online(node) ? node : NUMA_NO_NODE));
>>
>> - for_each_possible_cpu(cpu) {
>> - node = cpu_to_node(cpu);
>> - 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 */
>> - return;
>> - }
>> - cpumask_set_cpu(cpu, tbl[node]);
>> + cpumask_copy(tbl[node], cpumask_of_node(node));
>
> It is incorrect. cpumask_of_node(node) is the online cpumask of the node, not
> the possible cpumask of the node that we are interested in.
>
> If the NUMA subsystem provided something like cpumask_possible_of_node(node),
> we wouldn't need wq_numa_possible_cpumask.
>
> Please keep "for_each_possible_cpu(cpu)" loop and
> "cpumask_set_cpu(cpu, tbl[node]);"

OK.

>
>> }
>>
>> wq_numa_possible_cpumask = tbl;
>> --
>> 2.25.1
>>
> .
>