use rcu locks for find_task_by_pid().
Signed-off-by: Oleg Nesterov <[email protected]>
--- 2.6.18-rc4/kernel/futex.c~3_sgrl 2006-08-21 20:41:15.000000000 +0400
+++ 2.6.18-rc4/kernel/futex.c 2006-08-21 20:59:24.000000000 +0400
@@ -1682,7 +1682,7 @@ sys_get_robust_list(int pid, struct robu
struct task_struct *p;
ret = -ESRCH;
- read_lock(&tasklist_lock);
+ rcu_read_lock();
p = find_task_by_pid(pid);
if (!p)
goto err_unlock;
@@ -1691,7 +1691,7 @@ sys_get_robust_list(int pid, struct robu
!capable(CAP_SYS_PTRACE))
goto err_unlock;
head = p->robust_list;
- read_unlock(&tasklist_lock);
+ rcu_read_unlock();
}
if (put_user(sizeof(*head), len_ptr))
@@ -1699,7 +1699,7 @@ sys_get_robust_list(int pid, struct robu
return put_user(head, head_ptr);
err_unlock:
- read_unlock(&tasklist_lock);
+ rcu_read_unlock();
return ret;
}