From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 11D113AFB1C; Fri, 4 Sep 2026 05:42:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788500564; cv=none; b=emmamP2n3q3KoPvlLvD7MLLObyc66NLJQ5ZEmmg529sbl1HQdwmFAf76SqaSSv59vuvPL7IAMMxXkRgSwKaPrrHDavvmCHnnlC5EXL0MBwntNDURRG+Xz37xDVX6IS/4JcQ62SpxGtq7X5xiJaQUiG7xKmLC36g5m6rLrmCbpt8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788500564; c=relaxed/simple; bh=3Xrcyhi53jZLFe4gzKERyXqq2IAQNmPbKYv63Kx4t/o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rLBxDypZ0M2IUjCsM6+2cHhlqPgRo9HtcMnjAUZPFUZXMGBOq5KqdzYMPQYk/LaAeKwU5SAaQ5J54bWloO27VkBLyn5n8mveYnLROYDo75fqDhViS/S/IPJ3JyoXLa+t/Ni0cWpqXq+qU3M+1nmhLpIfne6UXLtkXsrr3cMZci4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hixT/Jjx; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="hixT/Jjx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6E1601F00A3D; Fri, 4 Sep 2026 05:42:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788500561; bh=sqLS8+S+eQRLpf+ZuCgyHVAj6m83PXrVsGHWaDBzAI0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=hixT/JjxDNXdkl1pCqGV8zJwhr+HbuFpi2RrCVyOqSsB0yzmvISLIABjcDiwnowec /7w0aMBxFN+uEAZtowzqLD5ujTKojqqKK26IwDcx0Xoym2gmLBVWfUxhklyTrLEZMB aubVppmfZiLEwgBOwO/esn6Rt12aUJFbvg2XROvM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Fan Wu Subject: [PATCH 6.18 073/552] usb: gadget: at91_udc: drain polled-VBUS timer/work before udc is freed Date: Fri, 4 Sep 2026 06:53:50 +0200 Message-ID: <20260904045749.503380662@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045747.813364717@linuxfoundation.org> References: <20260904045747.813364717@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: Fan Wu commit c27d13ce4bab80fbdf6523928071b6c24b37606c upstream. In polled-VBUS mode (board.vbus_pin && board.vbus_polled), probe arms a self-restarting cycle: at91_vbus_timer() schedules vbus_timer_work, and at91_vbus_timer_work() calls at91_vbus_update() and re-arms the timer via mod_timer(). Both recover the same udc through container_of and dereference it on every iteration. Neither teardown path cancels this cycle. udc is devm-allocated, so it is freed after at91udc_remove() returns, and is likewise freed when probe fails and devres runs. A timer callback or work item that is pending or running at either point dereferences the freed udc. Add at91_udc_shutdown_vbus_timer() and call it from at91udc_remove() and from the usb_add_gadget_udc() failure path in probe; the remaining probe error paths fail before the timer is armed. timer_shutdown_sync() waits for a running callback and clears timer->function, which makes the work handler's mod_timer() a permanent no-op; cancel_work_sync() then drains any pending or running work whose re-arm attempt now does nothing. The timer must be shut down first, since cancelling the work alone would let the timer re-queue it. The guard mirrors probe: in IRQ mode the timer and work_struct are never initialized. This does not require a fault; a normal driver unbind can interleave with an already queued work item. This issue was found by an in-house static analysis tool. Fixes: 4037242c4f5f ("ARM: 6209/3: at91_udc: Add vbus polarity and polling mode") Cc: stable@vger.kernel.org Assisted-by: Codex:gpt-5.6 Signed-off-by: Fan Wu Link: https://patch.msgid.link/20260719042839.3167094-1-fanwu01@zju.edu.cn Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/udc/at91_udc.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) --- a/drivers/usb/gadget/udc/at91_udc.c +++ b/drivers/usb/gadget/udc/at91_udc.c @@ -1794,6 +1794,19 @@ static void at91udc_of_init(struct at91_ udc->caps = match->data; } +/* + * The work handler re-arms this timer, so shut the timer down before + * draining the work; otherwise it restarts the polling cycle. + */ +static void at91_udc_shutdown_vbus_timer(struct at91_udc *udc) +{ + if (!(udc->board.vbus_pin && udc->board.vbus_polled)) + return; + + timer_shutdown_sync(&udc->vbus_timer); + cancel_work_sync(&udc->vbus_timer_work); +} + static int at91udc_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; @@ -1907,7 +1920,7 @@ static int at91udc_probe(struct platform } retval = usb_add_gadget_udc(dev, &udc->gadget); if (retval) - goto err_unprepare_iclk; + goto err_shutdown_vbus; dev_set_drvdata(dev, udc); device_init_wakeup(dev, 1); create_debug_file(udc); @@ -1915,6 +1928,8 @@ static int at91udc_probe(struct platform INFO("%s version %s\n", driver_name, DRIVER_VERSION); return 0; +err_shutdown_vbus: + at91_udc_shutdown_vbus_timer(udc); err_unprepare_iclk: clk_unprepare(udc->iclk); err_unprepare_fclk: @@ -1933,6 +1948,9 @@ static void at91udc_remove(struct platfo DBG("remove\n"); usb_del_gadget_udc(&udc->gadget); + + at91_udc_shutdown_vbus_timer(udc); + if (udc->driver) { dev_err(&pdev->dev, "Driver still in use but removing anyhow\n");