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>
diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index 8dca211..fdf5377 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -390,6 +390,7 @@
int cpu;
wait_queue_head_t queue;
+ struct completion start_done;
};
#define REMOVE 1
@@ -3414,6 +3415,7 @@
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 @@
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 @@
}
wake_up_process(p);
+ wait_for_completion(&t->start_done);
return 0;
}
