2024-02-28 00:58:30

by Waiman Long

Subject: [PATCH] cgroup/cpuset: Fix a memory leak in update_exclusive_cpumask()

Fix a possible memory leak in update_exclusive_cpumask() by moving the
alloc_cpumasks() down after the validate_change() check which can fail
and still before the temporary cpumasks are needed.

Fixes: e2ffe502ba45 ("cgroup/cpuset: Add cpuset.cpus.exclusive for v2")
Reported-by: Mirsad Todorovac <[email protected]>
Closes: https://lore.kernel.org/lkml/[email protected]
Signed-off-by: Waiman Long <[email protected]>
---
kernel/cgroup/cpuset.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index ba36c073304a..7260f095802a 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -2598,9 +2598,6 @@ static int update_exclusive_cpumask(struct cpuset *cs, struct cpuset *trialcs,
if (cpumask_equal(cs->exclusive_cpus, trialcs->exclusive_cpus))
return 0;

- if (alloc_cpumasks(NULL, &tmp))
- return -ENOMEM;
-
if (*buf)
compute_effective_exclusive_cpumask(trialcs, NULL);

@@ -2615,6 +2612,9 @@ static int update_exclusive_cpumask(struct cpuset *cs, struct cpuset *trialcs,
if (retval)
return retval;

+ if (alloc_cpumasks(NULL, &tmp))
+ return -ENOMEM;
+
if (old_prs) {
if (cpumask_empty(trialcs->effective_xcpus)) {
invalidate = true;
--
2.39.3

2024-02-28 14:19:42

by Mirsad Todorovac

Subject: Re: [PATCH] cgroup/cpuset: Fix a memory leak in update_exclusive_cpumask()

Hi,

On 2/28/2024 1:58 AM, Waiman Long wrote:
> Fix a possible memory leak in update_exclusive_cpumask() by moving the
> alloc_cpumasks() down after the validate_change() check which can fail
> and still before the temporary cpumasks are needed.
>
> Fixes: e2ffe502ba45 ("cgroup/cpuset: Add cpuset.cpus.exclusive for v2")
> Reported-by: Mirsad Todorovac <[email protected]>
> Closes: https://lore.kernel.org/lkml/[email protected]
> Signed-off-by: Waiman Long <[email protected]>
> ---
> kernel/cgroup/cpuset.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
> index ba36c073304a..7260f095802a 100644
> --- a/kernel/cgroup/cpuset.c
> +++ b/kernel/cgroup/cpuset.c
> @@ -2598,9 +2598,6 @@ static int update_exclusive_cpumask(struct cpuset *cs, struct cpuset *trialcs,
> if (cpumask_equal(cs->exclusive_cpus, trialcs->exclusive_cpus))
> return 0;
>
> - if (alloc_cpumasks(NULL, &tmp))
> - return -ENOMEM;
> -
> if (*buf)
> compute_effective_exclusive_cpumask(trialcs, NULL);
>
> @@ -2615,6 +2612,9 @@ static int update_exclusive_cpumask(struct cpuset *cs, struct cpuset *trialcs,
> if (retval)
> return retval;
>
> + if (alloc_cpumasks(NULL, &tmp))
> + return -ENOMEM;
> +
> if (old_prs) {
> if (cpumask_empty(trialcs->effective_xcpus)) {
> invalidate = true;Great work at such a short notice! (I failed to find the culprit myself.)

The leak is no longer present.

Please feel free to add:

Tested-by: Mirsad Todorovac <[email protected]>

Best regards, Mirsad Todorovac

P.S. APologies for the previous email accidentally sent as HTML.

2024-02-28 15:08:52

by Waiman Long

Subject: Re: [PATCH] cgroup/cpuset: Fix a memory leak in update_exclusive_cpumask()

On 2/28/24 08:56, Mirsad Todorovac wrote:
> Hi,
>
> On 2/28/2024 1:58 AM, Waiman Long wrote:
>> Fix a possible memory leak in update_exclusive_cpumask() by moving the
>> alloc_cpumasks() down after the validate_change() check which can fail
>> and still before the temporary cpumasks are needed.
>>
>> Fixes: e2ffe502ba45 ("cgroup/cpuset: Add cpuset.cpus.exclusive for v2")
>> Reported-by: Mirsad Todorovac <[email protected]>
>> Closes:
>> https://lore.kernel.org/lkml/[email protected]
>> Signed-off-by: Waiman Long <[email protected]>
>> ---
>>   kernel/cgroup/cpuset.c | 6 +++---
>>   1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
>> index ba36c073304a..7260f095802a 100644
>> --- a/kernel/cgroup/cpuset.c
>> +++ b/kernel/cgroup/cpuset.c
>> @@ -2598,9 +2598,6 @@ static int update_exclusive_cpumask(struct
>> cpuset *cs, struct cpuset *trialcs,
>>       if (cpumask_equal(cs->exclusive_cpus, trialcs->exclusive_cpus))
>>           return 0;
>>   -    if (alloc_cpumasks(NULL, &tmp))
>> -        return -ENOMEM;
>> -
>>       if (*buf)
>>           compute_effective_exclusive_cpumask(trialcs, NULL);
>>   @@ -2615,6 +2612,9 @@ static int update_exclusive_cpumask(struct
>> cpuset *cs, struct cpuset *trialcs,
>>       if (retval)
>>           return retval;
>>   +    if (alloc_cpumasks(NULL, &tmp))
>> +        return -ENOMEM;
>> +
>>       if (old_prs) {
>>           if (cpumask_empty(trialcs->effective_xcpus)) {
>>               invalidate = true;Great work at such a short notice! (I
>> failed to find the culprit myself.)
>
> The leak is no longer present.
>
> Please feel free to add:
>
> Tested-by: Mirsad Todorovac <[email protected]>
>
> Best regards, Mirsad Todorovac
>
> P.S. APologies for the previous email accidentally sent as HTML.

Thanks for verifying the fix.

Cheers,
Longman

2024-02-28 18:04:48

by Tejun Heo

Subject: Re: [PATCH] cgroup/cpuset: Fix a memory leak in update_exclusive_cpumask()

Hello,

On Tue, Feb 27, 2024 at 07:58:01PM -0500, Waiman Long wrote:
> Fix a possible memory leak in update_exclusive_cpumask() by moving the
> alloc_cpumasks() down after the validate_change() check which can fail
> and still before the temporary cpumasks are needed.
>
> Fixes: e2ffe502ba45 ("cgroup/cpuset: Add cpuset.cpus.exclusive for v2")
> Reported-by: Mirsad Todorovac <[email protected]>
> Closes: https://lore.kernel.org/lkml/[email protected]
> Signed-off-by: Waiman Long <[email protected]>

Applied to cgroup/for-6.8-fixes with stable cc'd. Depending on when v6.9
gets cut, this might go in together with for-6.9 during rc1.

Thanks.

--
tejun