[PATCH] CPU hotplug breaks wake_up_new_task

Fix a problem wherein a new-born task is added to a dead CPU.

Signed-off-by: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Acked-by: Nick Piggin <nickpiggin@yahoo.com.au>
Acked-by: Shaohua Li <shaohua.li@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
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 8149f3602881db80727310245436c97a661adf2a..533ce27f4b2c0938f91c948aa682bc992579ba96 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1062,7 +1062,8 @@ static task_t *copy_process(unsigned long clone_flags,
         * parent's CPU). This avoids alot of nasty races.
         */
        p->cpus_allowed = current->cpus_allowed;
-       if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed)))
+       if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) ||
+                       !cpu_online(task_cpu(p))))
                set_task_cpu(p, smp_processor_id());
 
        /*