Hi,

The suspend/hibernation is broken on SMP due to:

commit 3540af8ffddcdbc7573451ac0b5cd57a2eaf8af5
tifm: replace per-adapter kthread with freezeable workqueue

Well, it looks like freezable worqueues still deadlock with CPU hotplug
when worker threads are frozen.

The appended patch fixes the issue, but I think we could even avoid the
killing of frozen worker threads.

Greetings,
Rafael


---
Prevent freezable worqueues from deadlocking with CPU hotplug during a
suspend/hibernation by thawing their worker threads before they get stopped.

Signed-off-by: Rafael J. Wysocki <[EMAIL PROTECTED]>
---
 kernel/workqueue.c |   13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

Index: linux-2.6.22-rc1/kernel/workqueue.c
===================================================================
--- linux-2.6.22-rc1.orig/kernel/workqueue.c
+++ linux-2.6.22-rc1/kernel/workqueue.c
@@ -799,9 +799,7 @@ static int __devinit workqueue_cpu_callb
        struct cpu_workqueue_struct *cwq;
        struct workqueue_struct *wq;
 
-       action &= ~CPU_TASKS_FROZEN;
-
-       switch (action) {
+       switch (action & ~CPU_TASKS_FROZEN) {
        case CPU_LOCK_ACQUIRE:
                mutex_lock(&workqueue_mutex);
                return NOTIFY_OK;
@@ -819,20 +817,29 @@ static int __devinit workqueue_cpu_callb
 
                switch (action) {
                case CPU_UP_PREPARE:
+               case CPU_UP_PREPARE_FROZEN:
                        if (!create_workqueue_thread(cwq, cpu))
                                break;
                        printk(KERN_ERR "workqueue for %i failed\n", cpu);
                        return NOTIFY_BAD;
 
                case CPU_ONLINE:
+               case CPU_ONLINE_FROZEN:
                        start_workqueue_thread(cwq, cpu);
                        break;
 
                case CPU_UP_CANCELED:
+               case CPU_UP_CANCELED_FROZEN:
                        start_workqueue_thread(cwq, -1);
                case CPU_DEAD:
                        cleanup_workqueue_thread(cwq, cpu);
                        break;
+
+               case CPU_DEAD_FROZEN:
+                       if (wq->freezeable)
+                               thaw_process(cwq->thread);
+                       cleanup_workqueue_thread(cwq, cpu);
+                       break;
                }
        }
 
-
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