From: Serge E. Hallyn <serue@xxxxxxxxxx>
uids in namespaces other than init don't get a sysfs entry.
For those in the init namespace, while we're waiting to remove
the sysfs entry for the uid the uid is still hashed, and
alloc_uid() may re-grab that uid without getting a new
reference to the user_ns, which we've already put in free_user
before scheduling remove_user_sysfs_dir().
Reported-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Signed-off-by: Serge E. Hallyn <serue@xxxxxxxxxx>
Acked-by: David Howells <dhowells@xxxxxxxxxx>
Tested-by: Ingo Molnar <mingo@xxxxxxx>
---
kernel/user.c | 3 +--
1 files changed, 1 insertions(+), 2 deletions(-)
diff --git a/kernel/user.c b/kernel/user.c
index 477b666..3551ac7 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -72,6 +72,7 @@ static void uid_hash_insert(struct user_struct *up, struct hlist_head *hashent)
static void uid_hash_remove(struct user_struct *up)
{
hlist_del_init(&up->uidhash_node);
+ put_user_ns(up->user_ns);
}
static struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent)
@@ -334,7 +335,6 @@ static void free_user(struct user_struct *up, unsigned long flags)
atomic_inc(&up->__count);
spin_unlock_irqrestore(&uidhash_lock, flags);
- put_user_ns(up->user_ns);
INIT_WORK(&up->work, remove_user_sysfs_dir);
schedule_work(&up->work);
}
@@ -357,7 +357,6 @@ static void free_user(struct user_struct *up, unsigned long flags)
sched_destroy_user(up);
key_put(up->uid_keyring);
key_put(up->session_keyring);
- put_user_ns(up->user_ns);
kmem_cache_free(uid_cachep, up);
}
_______________________________________________
Containers mailing list
Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linux-foundation.org/mailman/listinfo/containers
