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

[Waiman Long]

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 <mirsad.todorovac@xxxxxx>
> > Closes: 
> > https://lore.kernel.org/lkml/14915689-27a3-4cd8-80d2-9c30d0c768b6@xxxxxxxxxxxx
> > Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
> > ---
> >   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 <mtodorov@xxxxxxxxxxxx>
>
> Best regards, Mirsad Todorovac
>
> P.S. APologies for the previous email accidentally sent as HTML.

Thanks for verifying the fix.

Cheers,
Longman