From d3ede327e83f202c3a0962e207318f65717c5eb7 Mon Sep 17 00:00:00 2001 From: "Denis V. Lunev" Date: Tue, 20 May 2008 15:12:44 -0700 Subject: [PATCH] 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 Acked-by: Alexey Dobriyan Signed-off-by: David S. Miller --- net/core/pktgen.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/core/pktgen.c b/net/core/pktgen.c index 8dca21110493..fdf537707e51 100644 --- a/net/core/pktgen.c +++ b/net/core/pktgen.c @@ -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; } -- 2.20.1