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authorSerge E. Hallyn <serue@us.ibm.com>2009-02-13 14:04:21 +0000
committerLinus Torvalds <torvalds@linux-foundation.org>2009-02-13 08:07:40 -0800
commitfb5ae64fdde29236e1a15e0366946df7060f41f2 (patch)
tree86be58998529fa84282ec1b98040d707e4b61686 /kernel/user.c
parent37bed90094fdb1eea6e4afec6a200d4e60143e55 (diff)
downloadvexpress-lsk-fb5ae64fdde29236e1a15e0366946df7060f41f2.tar.gz
User namespaces: Only put the userns when we unhash the uid
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-and-tested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Acked-by: David Howells <dhowells@redhat.com> Tested-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/user.c')
-rw-r--r--kernel/user.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/kernel/user.c b/kernel/user.c
index 477b6660f44..3551ac74239 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);
}