From d9be5e75530772fc31637070d51e5717d6aeaa2a Mon Sep 17 00:00:00 2001 From: Fan Wu Date: Thu, 10 Sep 2026 02:09:07 +0000 Subject: [PATCH] wifi: wcn36xx: Fix potential use-after-free in TX ack timer teardown wcn36xx_dxe_deinit() tears down the TX ack timer with timer_delete(), which only dequeues the timer and does not wait for a callback that is already executing; the preceding free_irq() calls synchronize the interrupt handlers only. The callback, wcn36xx_dxe_tx_timer(), can therefore be running past the teardown and use the wcn freed along with the ieee80211_hw in wcn36xx_remove(): it takes wcn->dxe_lock, reads wcn->tx_ack_skb and passes wcn->hw to ieee80211_tx_status_irqsafe(). Fix this by using timer_shutdown_sync(), which waits for a running callback and also prevents the timer from being rearmed again. The timer is set up again by wcn36xx_dxe_init() on the next start, so the start/stop cycle is unaffected. This issue was found by an in-house static analysis tool. Fixes: fdf21cc37149 ("wcn36xx: Add TX ack support") Cc: stable@vger.kernel.org Assisted-by: LLM Co-developed-by: Song Li Signed-off-by: Song Li Signed-off-by: Fan Wu Reviewed-by: Loic Poulain Link: https://patch.msgid.link/20260910020907.3353-1-fanwu01@zju.edu.cn Signed-off-by: Jeff Johnson --- drivers/net/wireless/ath/wcn36xx/dxe.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/wireless/ath/wcn36xx/dxe.c b/drivers/net/wireless/ath/wcn36xx/dxe.c index 44020ec265fb..801f1218ef89 100644 --- a/drivers/net/wireless/ath/wcn36xx/dxe.c +++ b/drivers/net/wireless/ath/wcn36xx/dxe.c @@ -1055,7 +1055,7 @@ void wcn36xx_dxe_deinit(struct wcn36xx *wcn) free_irq(wcn->tx_irq, wcn); free_irq(wcn->rx_irq, wcn); - timer_delete(&wcn->tx_ack_timer); + timer_shutdown_sync(&wcn->tx_ack_timer); if (wcn->tx_ack_skb) { ieee80211_tx_status_irqsafe(wcn->hw, wcn->tx_ack_skb);