From: frank.blaschka@de.ibm.com Subject: [patch 4/5] qeth: Fix crash on initial MTU size change Date: Mon, 24 Jun 2013 13:21:51 +0200 Message-ID: <20130624112226.756049779@de.ibm.com> References: <20130624112147.347247916@de.ibm.com> Return-path: Content-Disposition: inline; filename=603-qeth-initial-mtu-crash.diff Sender: netdev-owner@vger.kernel.org List-Archive: List-Post: To: davem@davemloft.net Cc: netdev@vger.kernel.org, linux-s390@vger.kernel.org, Stefan Raspl List-ID: From: Stefan Raspl When the initial MTU size is changed prior to any activity on the device (e.g. by attaching a z/VM vNIC already configured in Linux to a guestLAN), we call dev_kfree_skb_irq(NULL) which results in a kernel panic. Adding a proper check for NULL pointers to address this issue. Signed-off-by: Stefan Raspl Signed-off-by: Frank Blaschka Reviewed-by: Ursula Braun --- drivers/s390/net/qeth_core_main.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/drivers/s390/net/qeth_core_main.c +++ b/drivers/s390/net/qeth_core_main.c @@ -1282,8 +1282,10 @@ static void qeth_free_qdio_buffers(struc qeth_free_cq(card); cancel_delayed_work_sync(&card->buffer_reclaim_work); - for (j = 0; j < QDIO_MAX_BUFFERS_PER_Q; ++j) - dev_kfree_skb_any(card->qdio.in_q->bufs[j].rx_skb); + for (j = 0; j < QDIO_MAX_BUFFERS_PER_Q; ++j) { + if (card->qdio.in_q->bufs[j].rx_skb) + dev_kfree_skb_any(card->qdio.in_q->bufs[j].rx_skb); + } kfree(card->qdio.in_q); card->qdio.in_q = NULL; /* inbound buffer pool */