mISDN: Do not disable IRQ in ph_data_ind()

This fix triggering the WARN_ON_ONCE(in_irq() || irqs_disabled()); in
local_bh_enable().

Here is no need to grab this lock, this was wrong at all and may
cause a deadlock and access to freed memory, since on a TEI remove
the current listelement can be deleted under us. So this is clearly
a case for list_for_each_entry_safe.

Signed-off-by: Karsten Keil <keil@b1-systems.de>

1 files changed, 2 insertions, 5 deletions

diff --git a/drivers/isdn/mISDN/tei.c b/drivers/isdn/mISDN/tei.c
index bfcdd97df95d..e04bad6c5baf 100644
--- a/drivers/isdn/mISDN/tei.c
+++ b/drivers/isdn/mISDN/tei.c
@@ -862,8 +862,7 @@ static int
 ph_data_ind(struct manager *mgr, struct sk_buff *skb)
 {
         int             ret = -EINVAL;
-        struct layer2   *l2;
-        u_long          flags;
+        struct layer2   *l2, *nl2;
         u_char          mt;
 
         if (skb->len < 8) {
@@ -908,11 +907,9 @@ ph_data_ind(struct manager *mgr, struct sk_buff *skb)
                 new_tei_req(mgr, &skb->data[4]);
                 goto done;
         }
-        read_lock_irqsave(&mgr->lock, flags);
-        list_for_each_entry(l2, &mgr->layer2, list) {
+        list_for_each_entry_safe(l2, nl2, &mgr->layer2, list) {
                 tei_ph_data_ind(l2->tm, mt, &skb->data[4], skb->len - 4);
         }
-        read_unlock_irqrestore(&mgr->lock, flags);
 done:
         return ret;
 }