[PATCH] wcn36xx: handle rx skb allocation failure to avoid system crash
fengwei.yin
fengwei.yin at linaro.org
Fri Dec 11 05:14:04 PST 2015
On 2015/12/2 13:27, Fengwei Yin wrote:
> Lawrence reported that git clone could make system crash on a
> Qualcomm ARM soc based device (DragonBoard, 1G memory without
> swap) running 64bit Debian.
>
> It's turned out the crash is related with rx skb allocation
> failure. git could consume more than 600MB anonymous memory.
> And system is in extremely memory shortage case.
>
> But driver didn't handle the rx allocation failure case. This patch
> doesn't submit skb to upper layer if rx skb allocation fails.
> Instead, it reuse the old skb for rx DMA again. It's more like
> drop the packets if system is in memory shortage case.
>
> With this change, git clone is OOMed instead of system crash.
>
> Reported-by: King, Lawrence <lking at qti.qualcomm.com>
> Signed-off-by: Fengwei Yin <fengwei.yin at linaro.org>
> ---
> drivers/net/wireless/ath/wcn36xx/dxe.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/wcn36xx/dxe.c b/drivers/net/wireless/ath/wcn36xx/dxe.c
> index f8dfa05..8887c0f 100644
> --- a/drivers/net/wireless/ath/wcn36xx/dxe.c
> +++ b/drivers/net/wireless/ath/wcn36xx/dxe.c
> @@ -474,11 +474,20 @@ static int wcn36xx_rx_handle_packets(struct wcn36xx *wcn,
> struct wcn36xx_dxe_desc *dxe = ctl->desc;
> dma_addr_t dma_addr;
> struct sk_buff *skb;
> + int ret = 0;
>
> while (!(dxe->ctrl & WCN36XX_DXE_CTRL_VALID_MASK)) {
> skb = ctl->skb;
> dma_addr = dxe->dst_addr_l;
> - wcn36xx_dxe_fill_skb(wcn->dev, ctl);
> + ret = wcn36xx_dxe_fill_skb(wcn->dev, ctl);
> + if (0 == ret) {
> + /* new skb allocation ok. Use the new one and queue
> + * the old one to network system.
> + */
> + dma_unmap_single(wcn->dev, dma_addr, WCN36XX_PKT_SIZE,
> + DMA_FROM_DEVICE);
> + wcn36xx_rx_skb(wcn, skb);
> + }
>
> switch (ch->ch_type) {
> case WCN36XX_DXE_CH_RX_L:
> @@ -495,9 +504,6 @@ static int wcn36xx_rx_handle_packets(struct wcn36xx *wcn,
> wcn36xx_warn("Unknown channel\n");
> }
>
> - dma_unmap_single(wcn->dev, dma_addr, WCN36XX_PKT_SIZE,
> - DMA_FROM_DEVICE);
> - wcn36xx_rx_skb(wcn, skb);
> ctl = ctl->next;
> dxe = ctl->desc;
> }
>
Ping.... I am sure this is a fix according to the test I did.
Regards
Yin, Fengwei
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