wifi: rtlwifi: pci: fix possible use-after-free caused by unfinished irq_prepare_bcn_...

The irq_prepare_bcn_tasklet is initialized in rtl_pci_init() and
scheduled when RTL_IMR_BCNINT interrupt is triggered by hardware.
But it is never killed in rtl_pci_deinit(). When the rtlwifi card
probe fails or is being detached, the ieee80211_hw is deallocated.
However, irq_prepare_bcn_tasklet may still be running or pending,
leading to use-after-free when the freed ieee80211_hw is accessed
in _rtl_pci_prepare_bcn_tasklet().

Similar to irq_tasklet, add tasklet_kill() in rtl_pci_deinit() to
ensure that irq_prepare_bcn_tasklet is properly terminated before
the ieee80211_hw is released.

The issue was identified through static analysis.

Fixes: 0c8173385e54 ("rtl8192ce: Add new driver")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20260223045522.48377-1-duoming@zju.edu.cn

diff --git a/drivers/net/wireless/realtek/rtlwifi/pci.c b/drivers/net/wireless/realtek/rtlwifi/pci.c
index d080469264cf89eb96cf75304c946d2388421586..f0010336e78c1b73861a53f09642517f8304ed94 100644 (file)
--- a/drivers/net/wireless/realtek/rtlwifi/pci.c
+++ b/drivers/net/wireless/realtek/rtlwifi/pci.c
@@ -1674,6 +1674,7 @@ static void rtl_pci_deinit(struct ieee80211_hw *hw)
 
        synchronize_irq(rtlpci->pdev->irq);
        tasklet_kill(&rtlpriv->works.irq_tasklet);
+       tasklet_kill(&rtlpriv->works.irq_prepare_bcn_tasklet);
        cancel_work_sync(&rtlpriv->works.lps_change_work);
 }