Re: [PATCH 6.1.y] Fix memory leak in io_wq_create() on success path

On Thu, Aug 06, 2026 at 10:47:02PM +0800, xk c wrote:
> Greg KH <[email protected]> 于2026年8月6日周四 22:33写道：
> >
> > On Thu, Aug 06, 2026 at 10:23:14PM +0800, Chen Xiaokun wrote:
> > > The commit 657ca82526d0 introduced a temporary allowed_mask cpumask in
> > > io_wq_create(), which was freed only on the error path.  This caused a
> > > memory leak of cpumask_size() bytes on every successful io_wq_create().
> > >
> > > Fixes: 657ca82526d0 ("io_uring/io-wq: inherit cpuset of cgroup in io worker")
> > > Signed-off-by: Chen Xiaokun <[email protected]>
> > > ---
> > >  io_uring/io-wq.c | 1 +
> > >  1 file changed, 1 insertion(+)
> > >
> > > diff --git a/io_uring/io-wq.c b/io_uring/io-wq.c
> > > index 66fdd69fd6cb..34a1a9067cc2 100644
> > > --- a/io_uring/io-wq.c
> > > +++ b/io_uring/io-wq.c
> > > @@ -1218,6 +1218,7 @@ struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
> > >       wq->task = get_task_struct(data->task);
> > >       atomic_set(&wq->worker_refs, 1);
> > >       init_completion(&wq->worker_done);
> > > +     free_cpumask_var(allowed_mask);
> > >       return wq;
> > >  err:
> > >       io_wq_put_hash(data->hash);
> > > --
> > > 2.55.0
> > >
> > >
> >
> > Why is this a stable-only patch?  Was the backport wrong?  Or is this
> > also in Linus's tree?
> >
> 
> Linus's tree has not this issue.

You need to explain why, in great detail, Linus's tree does not have
this problem in the changelog.

For example, try answering the questions I asked here, that should
provide you a framework for what to write.

thnanks,

greg k-h