Commit d3ede327 authored by Denis V. Lunev's avatar Denis V. Lunev Committed by David S. Miller

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: default avatarDenis V. Lunev <den@openvz.org>
Acked-by: default avatarAlexey Dobriyan <adobriyan@openvz.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 5fb13570
...@@ -390,6 +390,7 @@ struct pktgen_thread { ...@@ -390,6 +390,7 @@ struct pktgen_thread {
int cpu; int cpu;
wait_queue_head_t queue; wait_queue_head_t queue;
struct completion start_done;
}; };
#define REMOVE 1 #define REMOVE 1
...@@ -3414,6 +3415,7 @@ static int pktgen_thread_worker(void *arg) ...@@ -3414,6 +3415,7 @@ static int pktgen_thread_worker(void *arg)
BUG_ON(smp_processor_id() != cpu); BUG_ON(smp_processor_id() != cpu);
init_waitqueue_head(&t->queue); init_waitqueue_head(&t->queue);
complete(&t->start_done);
pr_debug("pktgen: starting pktgen/%d: pid=%d\n", cpu, task_pid_nr(current)); 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) ...@@ -3615,6 +3617,7 @@ static int __init pktgen_create_thread(int cpu)
INIT_LIST_HEAD(&t->if_list); INIT_LIST_HEAD(&t->if_list);
list_add_tail(&t->th_list, &pktgen_threads); list_add_tail(&t->th_list, &pktgen_threads);
init_completion(&t->start_done);
p = kthread_create(pktgen_thread_worker, t, "kpktgend_%d", cpu); p = kthread_create(pktgen_thread_worker, t, "kpktgend_%d", cpu);
if (IS_ERR(p)) { if (IS_ERR(p)) {
...@@ -3639,6 +3642,7 @@ static int __init pktgen_create_thread(int cpu) ...@@ -3639,6 +3642,7 @@ static int __init pktgen_create_thread(int cpu)
} }
wake_up_process(p); wake_up_process(p);
wait_for_completion(&t->start_done);
return 0; return 0;
} }
......
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