The patch titled
user namespaces: only put the userns when we unhash the uid
has been added to the -mm tree. Its filename is
user-namespaces-only-put-the-userns-when-we-unhash-the-uid.patch
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Subject: user namespaces: only put the userns when we unhash the uid
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().
Signed-off-by: Serge E. Hallyn <serue@xxxxxxxxxx>
Acked-by: David Howells <dhowells@xxxxxxxxxx>
Cc: Vegard Nossum <vegard.nossum@xxxxxxxxx>
Cc: Eric Sesterhenn <snakebyte@xxxxxx>
Cc: Dhaval Giani <dhaval@xxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/user.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff -puN kernel/user.c~user-namespaces-only-put-the-userns-when-we-unhash-the-uid kernel/user.c
--- a/kernel/user.c~user-namespaces-only-put-the-userns-when-we-unhash-the-uid
+++ a/kernel/user.c
@@ -72,6 +72,7 @@ static void uid_hash_insert(struct user_
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
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
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);
}
_
Patches currently in -mm which might be from serue@xxxxxxxxxx are
linux-next.patch
vfs-simple_set_mnt-should-return-void.patch
user-namespaces-only-put-the-userns-when-we-unhash-the-uid.patch
relax-ns_can_attach-checks-to-allow-attaching-to-grandchild-cgroups.patch
pids-kill-now-unused-signal_struct-__pgrp-__session-and-friends.patch
reiser4.patch
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