Commit d3ede327 authored May 20, 2008 by Denis V. Lunev Committed by David S. Miller May 20, 2008

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>

parent 5fb13570

net/core/pktgen.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -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;
		}

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