RE: [PATCH v3] wifi: rtw88: usb: fix memory leaks on USB write failures

[Ping-Ke Shih <pkshih@realtek.com>]

luka.gejak@linux.dev <luka.gejak@linux.dev> wrote: 
> From: Luka Gejak <luka.gejak@linux.dev>
> 
> When rtw_usb_write_port() fails to submit a USB Request Block (URB)
> (e.g., due to device disconnect or ENOMEM), the completion callback is
> never executed.
> 
> Currently, the driver ignores the return value of rtw_usb_write_port()
> in rtw_usb_write_data() and rtw_usb_tx_agg_skb(). Because these
> functions rely on the completion callback to free the socket buffers
> (skbs) and the transaction control block (txcb), a submission failure
> results in:
> 1. A memory leak of the allocated skb in rtw_usb_write_data().
> 2. A memory leak of the txcb structure and all aggregated skbs in
>    rtw_usb_tx_agg_skb().
> 
> Fix this by checking the return value of rtw_usb_write_port(). If it
> fails, explicitly free the skb in rtw_usb_write_data(), and properly
> purge the tx_ack_queue and free the txcb in rtw_usb_tx_agg_skb().
> 
> The issue was discovered in practice during device disconnect/reconnect
> scenarios and memory pressure conditions. Tested by verifying normal TX
> operation continues after the fix without regressions.
> 
> Fixes: a82dfd33d123 ("wifi: rtw88: Add common USB chip support")
> Cc: stable@vger.kernel.org
> Tested-by: Luka Gejak <luka.gejak@linux.dev>
> Signed-off-by: Luka Gejak <luka.gejak@linux.dev>

Acked-by: Ping-Ke Shih <pkshih@realtek.com>