[PATCH] cpuset fork locking fix

Move the cpuset_fork() call below the write_unlock_irq call in
kernel/fork.c copy_process().

Since the cpuset-dual-semaphore-locking-overhaul.patch, the cpuset_fork()
routine acquires task_lock(), so cannot be called while holding the
tasklist_lock for write.

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/kernel/fork.c b/kernel/fork.c
index d0d4987..fb8572a 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1124,8 +1124,6 @@ static task_t *copy_process(unsigned long clone_flags,
        if (unlikely(p->ptrace & PT_PTRACED))
                __ptrace_link(p, current->parent);
 
-       cpuset_fork(p);
-
        attach_pid(p, PIDTYPE_PID, p->pid);
        attach_pid(p, PIDTYPE_TGID, p->tgid);
        if (thread_group_leader(p)) {
@@ -1142,6 +1140,7 @@ static task_t *copy_process(unsigned long clone_flags,
        total_forks++;
        write_unlock_irq(&tasklist_lock);
        proc_fork_connector(p);
+       cpuset_fork(p);
        retval = 0;
 
 fork_out: