On Mon, Nov 16, 2020 at 02:00:54AM +0800, Hui Su wrote:
> Use put_nsproxy() instead of '
> if (atomic_dec_and_test(&ns->count)) {
> free_nsproxy(ns);
> }' in switch_task_namespaces().
>
> and remove the whitespace by the way.
>
> Signed-off-by: Hui Su
> ---
Acked-by: Christian Brauner
Thanks! I'm picking this up now.
I'll add to the commit message though sm like:
"We already have a dedicated helper that handles reference count
checking so stop open-coding the reference count check in
switch_task_namespaces() and use the dedicated put_nsproxy() helper
instead."
(Looking at put_nsproxy() I feel we should probably start mandating that
all free()/put() helpers should gracefully handle when passed NULL to
avoid:
if (ns)
put()
calls. But that's independent of this fix.)
> kernel/nsproxy.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
> index 12dd41b39a7f..3ebfd090398a 100644
> --- a/kernel/nsproxy.c
> +++ b/kernel/nsproxy.c
> @@ -173,7 +173,7 @@ int copy_namespaces(unsigned long flags, struct
> task_struct *tsk)
>* it along with CLONE_NEWIPC.
>*/
> if ((flags & (CLONE_NEWIPC | CLONE_SYSVSEM)) ==
> - (CLONE_NEWIPC | CLONE_SYSVSEM))
> + (CLONE_NEWIPC | CLONE_SYSVSEM))
> return -EINVAL;
>
> new_ns = create_new_namespaces(flags, tsk, user_ns, tsk->fs);
> @@ -250,8 +250,8 @@ void switch_task_namespaces(struct task_struct *p, struct
> nsproxy *new)
> p->nsproxy = new;
> task_unlock(p);
>
> - if (ns && atomic_dec_and_test(&ns->count))
> - free_nsproxy(ns);
> + if (ns)
> + put_nsproxy(ns);
> }
>
> void exit_task_namespaces(struct task_struct *p)
> --
> 2.29.0
>
>
