[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>

1 files changed, 2 insertions, 1 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index 8149f3602881..533ce27f4b2c 100644
--- 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());
 
         /*