From 6e4af087c8e050d72f9aad8fd342260f9b277298 Mon Sep 17 00:00:00 2001 From: Yan-Hsuan Chuang Date: Tue, 7 Jan 2020 16:08:07 +0800 Subject: [PATCH] rtw88: fix potential NULL skb access in TX ISR [ Upstream commit f4f84ff8377d4cedf18317747bc407b2cf657d0f ] Sometimes the TX queue may be empty and we could possible dequeue a NULL pointer, crash the kernel. If the skb is NULL then there is nothing to do, just leave the ISR. And the TX queue should not be empty here, so print an error to see if there is anything wrong for DMA ring. Fixes: e3037485c68e ("rtw88: new Realtek 802.11ac driver") Signed-off-by: Yan-Hsuan Chuang Signed-off-by: Kalle Valo Signed-off-by: Sasha Levin --- drivers/net/wireless/realtek/rtw88/pci.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/net/wireless/realtek/rtw88/pci.c b/drivers/net/wireless/realtek/rtw88/pci.c index a58e8276a41a..a6746b5a9ff2 100644 --- a/drivers/net/wireless/realtek/rtw88/pci.c +++ b/drivers/net/wireless/realtek/rtw88/pci.c @@ -832,6 +832,11 @@ static void rtw_pci_tx_isr(struct rtw_dev *rtwdev, struct rtw_pci *rtwpci, while (count--) { skb = skb_dequeue(&ring->queue); + if (!skb) { + rtw_err(rtwdev, "failed to dequeue %d skb TX queue %d, BD=0x%08x, rp %d -> %d\n", + count, hw_queue, bd_idx, ring->r.rp, cur_rp); + break; + } tx_data = rtw_pci_get_tx_data(skb); pci_unmap_single(rtwpci->pdev, tx_data->dma, skb->len, PCI_DMA_TODEVICE);