1) Remove the misleading comment in __sigqueue_alloc() which claims
that holding a spinlock is equivalent to rcu_read_lock().
2) Add a rcu_read_lock/unlock around the __task_cred() access
in __sigqueue_alloc()
This needs to be revisited to remove the remaining users of
read_lock(&tasklist_lock) but that's outside the scope of this patch.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <
20091210004703.
269843657@linutronix.de>
struct user_struct *user;
/*
- * We won't get problems with the target's UID changing under us
- * because changing it requires RCU be used, and if t != current, the
- * caller must be holding the RCU readlock (by way of a spinlock) and
- * we use RCU protection here
+ * Protect access to @t credentials. This can go away when all
+ * callers hold rcu read lock.
*/
+ rcu_read_lock();
user = get_uid(__task_cred(t)->user);
atomic_inc(&user->sigpending);
+ rcu_read_unlock();
if (override_rlimit ||
atomic_read(&user->sigpending) <=