2022-12-07 14:23:57

by Yang Yingliang

Subject: [PATCH v3 1/3] wifi: rtlwifi: rtl8821ae: don't call kfree_skb() under spin_lock_irqsave()

It is not allowed to call kfree_skb() from hardware interrupt
context or with interrupts being disabled. All the SKBs have
been dequeued from the old queue, so it's safe to enqueue these
SKBs to a free queue, then free them after spin_unlock_irqrestore()
at once. Compile tested only.

Fixes: 5c99f04fec93 ("rtlwifi: rtl8723be: Update driver to match Realtek release of 06/28/14")
Signed-off-by: Yang Yingliang <[email protected]>
Acked-by: Ping-Ke Shih <[email protected]>
---
drivers/net/wireless/realtek/rtlwifi/rtl8821ae/hw.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8821ae/hw.c b/drivers/net/wireless/realtek/rtlwifi/rtl8821ae/hw.c
index 7e0f62d59fe1..a7e3250957dc 100644
--- a/drivers/net/wireless/realtek/rtlwifi/rtl8821ae/hw.c
+++ b/drivers/net/wireless/realtek/rtlwifi/rtl8821ae/hw.c
@@ -26,8 +26,10 @@ static void _rtl8821ae_return_beacon_queue_skb(struct ieee80211_hw *hw)
struct rtl_priv *rtlpriv = rtl_priv(hw);
struct rtl_pci *rtlpci = rtl_pcidev(rtl_pcipriv(hw));
struct rtl8192_tx_ring *ring = &rtlpci->tx_ring[BEACON_QUEUE];
+ struct sk_buff_head free_list;
unsigned long flags;

+ skb_queue_head_init(&free_list);
spin_lock_irqsave(&rtlpriv->locks.irq_th_lock, flags);
while (skb_queue_len(&ring->queue)) {
struct rtl_tx_desc *entry = &ring->desc[ring->idx];
@@ -37,10 +39,12 @@ static void _rtl8821ae_return_beacon_queue_skb(struct ieee80211_hw *hw)
rtlpriv->cfg->ops->get_desc(hw, (u8 *)entry,
true, HW_DESC_TXBUFF_ADDR),
skb->len, DMA_TO_DEVICE);
- kfree_skb(skb);
+ __skb_queue_tail(&free_list, skb);
ring->idx = (ring->idx + 1) % ring->entries;
}
spin_unlock_irqrestore(&rtlpriv->locks.irq_th_lock, flags);
+
+ __skb_queue_purge(&free_list);
}

static void _rtl8821ae_set_bcn_ctrl_reg(struct ieee80211_hw *hw,
--
2.25.1

2022-12-14 12:30:09

by Kalle Valo

Subject: Re: [PATCH v3 1/3] wifi: rtlwifi: rtl8821ae: don't call kfree_skb() under spin_lock_irqsave()

Yang Yingliang <[email protected]> wrote:

> It is not allowed to call kfree_skb() from hardware interrupt
> context or with interrupts being disabled. All the SKBs have
> been dequeued from the old queue, so it's safe to enqueue these
> SKBs to a free queue, then free them after spin_unlock_irqrestore()
> at once. Compile tested only.
>
> Fixes: 5c99f04fec93 ("rtlwifi: rtl8723be: Update driver to match Realtek release of 06/28/14")
> Signed-off-by: Yang Yingliang <[email protected]>
> Acked-by: Ping-Ke Shih <[email protected]>

3 patches applied to wireless-next.git, thanks.

106031c1f4a8 wifi: rtlwifi: rtl8821ae: don't call kfree_skb() under spin_lock_irqsave()
2611687fa7ff wifi: rtlwifi: rtl8188ee: don't call kfree_skb() under spin_lock_irqsave()
313950c2114e wifi: rtlwifi: rtl8723be: don't call kfree_skb() under spin_lock_irqsave()

--
https://patchwork.kernel.org/project/linux-wireless/patch/[email protected]/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches