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 B4B593B388C; Sat, 17 Oct 2026 17:07:21 +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=1792256843; cv=none; b=QuC2J3TVlHN1y2W6gPkzmxHeyoRPgAjdT7/rft+tmlbmUQ1N/tHafui6mK/D2tE0t3UVzjPkiV1a/CPgisWcEGjjqelzgjIcrYCTDO4PUVvS0h0yqLigSPQ/fjotGcsuqrVLpTgP1EXb0leLGz6RLKpgmbUBfXYQL5sDzEiuwO0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792256843; c=relaxed/simple; bh=VSuTx0AniP4HxwSE08nBzyRVgmPqHPbRjlutO+qdXuI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=LgxO85RvG7CcwbzVdZu+CjDZu2vXfkGbEcLtsH+CAlsTbbW3tfzEcoJ3EQY9nPFhCTrC4X6dwuvRF10uGb/FCvx8+rixQ0GQz2mHoLFHv5CK7FvShbrdzcjxhQCsSJOMH8BaYo3XKdc3fZDckSfikskvPhis7BMbJTxgB0gZ0No= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1J0WAcho; 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="1J0WAcho" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0DE2E1F000C4; Sat, 17 Oct 2026 17:07:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792256841; bh=PbTlaBD3v2k2fiIKuRhp40iCRBVMlZ2oP41+W9G9A1o=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=1J0WAchovdiUKcPE/gBymptd4yHxPkiwH7a6BYDhV6rjqyrT8QKWOXDjbXAOfd0eJ ZN/xBkG8JUMA7whqAsDeO+I8uHZSn99JHgRSy9kZA/aWqrq0aT7CdXGFvDZxnketRM 43sjoSXbkQifQLQUdRzt1Xu0tlj7wJBgWtmjgeV8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Fan Wu , Sasha Levin Subject: [PATCH 6.6 0369/1674] usb: gadget: at91_udc: drain polled-VBUS timer/work before udc is freed Date: Sat, 17 Oct 2026 17:44:01 +0200 Message-ID: <20261017160440.591293069@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160431.119607952@linuxfoundation.org> References: <20261017160431.119607952@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Fan Wu [ Upstream commit c27d13ce4bab80fbdf6523928071b6c24b37606c ] 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 Signed-off-by: Sasha Levin 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 @@ -1793,6 +1793,19 @@ 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; @@ -1906,7 +1919,7 @@ 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); @@ -1914,6 +1927,8 @@ 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: @@ -1932,6 +1947,9 @@ 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");