From d153218b8e4c591c1615d723c46f9419a12fc430 Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Thu, 16 Apr 2026 17:33:39 +0800 Subject: [PATCH] wifi: brcmfmac: Fix potential use-after-free issue when stopping watchdog task ANBZ: #36646 commit c623b63580880cc742255eaed3d79804c1b91143 upstream. Watchdog task might end between send_sig() and kthread_stop() calls, what results in the use-after-free issue. Fix this by increasing watchdog task reference count before calling send_sig() and dropping it by switching to kthread_stop_put(). Cc: stable@vger.kernel.org Fixes: 373c83a801f1 ("brcmfmac: stop watchdog before detach and free everything") Fixes: a9ffda88be74 ("brcm80211: fmac: abstract bus_stop interface function pointer") Signed-off-by: Marek Szyprowski Acked-by: Arend van Spriel Link: https://patch.msgid.link/20260416093339.2066829-1-m.szyprowski@samsung.com Signed-off-by: Johannes Berg Fixes: CVE-2026-46180 Assisted-by: PatchPilot Signed-off-by: Xunlei Pang --- drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c index 9929e90866f0..80275b0758f0 100644 --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c @@ -2464,8 +2464,9 @@ static void brcmf_sdio_bus_stop(struct device *dev) brcmf_dbg(TRACE, "Enter\n"); if (bus->watchdog_tsk) { + get_task_struct(bus->watchdog_tsk); send_sig(SIGTERM, bus->watchdog_tsk, 1); - kthread_stop(bus->watchdog_tsk); + kthread_stop_put(bus->watchdog_tsk); bus->watchdog_tsk = NULL; } @@ -4531,8 +4532,9 @@ void brcmf_sdio_remove(struct brcmf_sdio *bus) if (bus) { /* Stop watchdog task */ if (bus->watchdog_tsk) { + get_task_struct(bus->watchdog_tsk); send_sig(SIGTERM, bus->watchdog_tsk, 1); - kthread_stop(bus->watchdog_tsk); + kthread_stop_put(bus->watchdog_tsk); bus->watchdog_tsk = NULL; } -- Gitee