CRED: Use RCU to access another task's creds and to release a task's own creds

Use RCU to access another task's creds and to release a task's own creds.
This means that it will be possible for the credentials of a task to be
replaced without another task (a) requiring a full lock to read them, and (b)
seeing deallocated memory.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 3af787ba2077..0e0b282a2073 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -298,9 +298,9 @@ static void dump_tasks(const struct mem_cgroup *mem)
 
                 task_lock(p);
                 printk(KERN_INFO "[%5d] %5d %5d %8lu %8lu %3d     %3d %s\n",
-                       p->pid, p->cred->uid, p->tgid, p->mm->total_vm,
-                       get_mm_rss(p->mm), (int)task_cpu(p), p->oomkilladj,
-                       p->comm);
+                       p->pid, __task_cred(p)->uid, p->tgid,
+                       p->mm->total_vm, get_mm_rss(p->mm), (int)task_cpu(p),
+                       p->oomkilladj, p->comm);
                 task_unlock(p);
         } while_each_thread(g, p);
 }