From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 351533BB13F; Tue, 12 May 2026 17:53:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778608438; cv=none; b=rSAUhQz4DLcV3hiL0zbbhIEUlejeNB5ROSo4ckruyWD6DB4BQRLUKsaoRuR9nmSZ2WxCaWJml3zVCfPCe1enjId5T0X8HVoFmwx0ohbjUvyGD7D6JGmTKindeSewWo5n7jP4zcgGcT0YWvfpKr/Z+sp760JOlnR/Jch5LUeRcYA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778608438; c=relaxed/simple; bh=EmPxuYYylQ3ev/E9W8b9EFrqAA7GoI1nyATEPLC0KK8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=V6E1cYj3kZruPUVenzBzY+iYeUMc0iYc8H/+yNMMZvtSRzjaagXMZ1WEqIidZN9WgZb1XCOkncz2VKZht4w9ltD2YzfF5jXZZOoXsm0IgmnYlQk1JcAEbePqpb9L6deRj+DDHtCCUEOEpSoif9/gFRAF3bdFSc8SVHYXInmXylU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=FmEQuP3l; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="FmEQuP3l" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D536C2BCB0; Tue, 12 May 2026 17:53:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778608437; bh=EmPxuYYylQ3ev/E9W8b9EFrqAA7GoI1nyATEPLC0KK8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FmEQuP3l8QOk8DLzw5JpclJQOSxbltVfAkFEmHLCsMKULeH0k0YztnDgJqLY+ZJYO AXxscZ+Ux6u9nYpxWyIPrSskyd57lLnEFVZlnHFSj/lyWe6O+Aap9Wq89HMFFY/ASb D1ngImxSZO1a0kauo2qfVbMRD6tzXRS6d3YLkAdQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Marek Szyprowski , Arend van Spriel , Johannes Berg Subject: [PATCH 6.18 037/270] wifi: brcmfmac: Fix potential use-after-free issue when stopping watchdog task Date: Tue, 12 May 2026 19:37:18 +0200 Message-ID: <20260512173939.236368162@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260512173938.452574370@linuxfoundation.org> References: <20260512173938.452574370@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Marek Szyprowski 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 Signed-off-by: Greg Kroah-Hartman --- drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c @@ -2476,8 +2476,9 @@ static void brcmf_sdio_bus_stop(struct d 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; } @@ -4567,8 +4568,9 @@ void brcmf_sdio_remove(struct brcmf_sdio 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; }