[PATCH 1/1] user namespaces: only put the userns when we unhash the uid
Serge E. Hallyn
serue at us.ibm.com
Wed Feb 11 08:29:52 PST 2009
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().
Signed-off-by: Serge E. Hallyn <serue at us.ibm.com>
---
kernel/user.c | 3 +--
1 files changed, 1 insertions(+), 2 deletions(-)
diff --git a/kernel/user.c b/kernel/user.c
index 477b666..bb401a5 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -71,6 +71,7 @@ static void uid_hash_insert(struct user_struct *up, struct hlist_head *hashent)
static void uid_hash_remove(struct user_struct *up)
{
+ put_user_ns(up->user_ns);
hlist_del_init(&up->uidhash_node);
}
@@ -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);
}
--
1.6.1
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