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pktgen: make sure that pktgen_thread_worker has been executed 

The following courruption can happen during pktgen stop:
list_del corruption. prev->next should be ffff81007e8a5e70, but was 6b6b6b6b6b6b6b6b
kernel BUG at lib/list_debug.c:67!
      :pktgen:pktgen_thread_worker+0x374/0x10b0
      ? autoremove_wake_function+0x0/0x40
      ? _spin_unlock_irqrestore+0x42/0x80
      ? :pktgen:pktgen_thread_worker+0x0/0x10b0
      kthread+0x4d/0x80
      child_rip+0xa/0x12
      ? restore_args+0x0/0x30
      ? kthread+0x0/0x80
      ? child_rip+0x0/0x12
RIP  list_del+0x48/0x70

The problem is that pktgen_thread_worker can not be executed if kthread_stop
has been called too early. Insert a completion on the normal initialization
path to make sure that pktgen_thread_worker will gain the control for sure.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Acked-by: Alexey Dobriyan <adobriyan@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Denis V. Lunev 2008-05-20 15:12:44 -07:00 committed by David S. Miller
parent 5fb1357054
commit d3ede327e8
1 changed files with 4 additions and 0 deletions
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4
net/core/pktgen.c
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@ -390,6 +390,7 @@ struct pktgen_thread {
int cpu;
wait_queue_head_t queue;
struct completion start_done;
};
#define REMOVE 1
@ -3414,6 +3415,7 @@ static int pktgen_thread_worker(void *arg)
BUG_ON(smp_processor_id() != cpu);
init_waitqueue_head(&t->queue);
complete(&t->start_done);
pr_debug("pktgen: starting pktgen/%d: pid=%d\n", cpu, task_pid_nr(current));
@ -3615,6 +3617,7 @@ static int __init pktgen_create_thread(int cpu)
INIT_LIST_HEAD(&t->if_list);
list_add_tail(&t->th_list, &pktgen_threads);
init_completion(&t->start_done);
p = kthread_create(pktgen_thread_worker, t, "kpktgend_%d", cpu);
if (IS_ERR(p)) {
@ -3639,6 +3642,7 @@ static int __init pktgen_create_thread(int cpu)
}
wake_up_process(p);
wait_for_completion(&t->start_done);
return 0;
}