On Fri, Apr 26, 2024 at 03:53:48PM -0400, Lucas Karpinski wrote:
> -static void namespace_unlock(void)
> +static void free_mounts(struct hlist_head *mount_list)
> {
> - struct hlist_head head;
> struct hlist_node *p;
> struct mount *m;
> +
> + hlist_for_each_entry_safe(m, p, mount_list, mnt_umount) {
> + hlist_del(&m->mnt_umount);
> + mntput(&m->mnt);
... which may block in quite a few ways.
> + }
> +}
> +
> +static void delayed_mount_release(struct rcu_head *head)
> +{
> + struct mount_delayed_release *drelease =
> + container_of(head, struct mount_delayed_release, rcu);
> +
> + free_mounts(&drelease->release_list);
... and therefore so can this.
> + kfree(drelease);
> +}
> + call_rcu(&drelease->rcu, delayed_mount_release);
... which is a bad idea, since call_rcu() callbacks are run
from interrupt context. Which makes blocking in them a problem.
