Fix failure path in alloc_pid()

commit 1a80dade010c7a7f4885a4c4c2a7ac22cc7b34df upstream.

The failure path removes the allocated PIDs from the wrong namespace.
This could lead to us inadvertently reusing PIDs in the leaf namespace
and leaking PIDs in parent namespaces.

Fixes: 95846ecf9dac ("pid: replace pid bitmap implementation with IDR API")
Cc: <stable@vger.kernel.org>
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/pid.c b/kernel/pid.c
index b2f6c506035da7c75b6b7e277f8d7c1a7ee244a2..20881598bdfaccc2e0ad736e1e2f8228ca3299bf 100644 (file)
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -233,8 +233,10 @@ out_unlock:
 
 out_free:
        spin_lock_irq(&pidmap_lock);
-       while (++i <= ns->level)
-               idr_remove(&ns->idr, (pid->numbers + i)->nr);
+       while (++i <= ns->level) {
+               upid = pid->numbers + i;
+               idr_remove(&upid->ns->idr, upid->nr);
+       }
 
        /* On failure to allocate the first pid, reset the state */
        if (ns->pid_allocated == PIDNS_ADDING)