1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/isdn/hardware/avm/c4.c b/drivers/isdn/hardware/avm/c4.c
index 8710cf6214d9..4bbbbe688077 100644
--- a/drivers/isdn/hardware/avm/c4.c
+++ b/drivers/isdn/hardware/avm/c4.c
@@ -678,7 +678,9 @@ static irqreturn_t c4_handle_interrupt(avmcard *card)
                 for (i=0; i < card->nr_controllers; i++) {
                         avmctrl_info *cinfo = &card->ctrlinfo[i];
                         memset(cinfo->version, 0, sizeof(cinfo->version));
+                        spin_lock_irqsave(&card->lock, flags);
                         capilib_release(&cinfo->ncci_head);
+                        spin_unlock_irqrestore(&card->lock, flags);
                         capi_ctr_reseted(&cinfo->capi_ctrl);
                 }
                 card->nlogcontr = 0;