From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 24B12C43381 for ; Fri, 22 Mar 2019 12:45:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EA8312070D for ; Fri, 22 Mar 2019 12:45:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553258742; bh=sBJrwuKBclQrBq3lXjS0PqgDZrDahtN5SSz1wa6yTas=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=K2yaJEwsgQdiRMK0ag4sJG03dzvvI9JxIIJaIxy43H6H/40MXHC5lIlD6/OzZTvNo T4nKS8FV9W6DmS8DnrRHbuJDmuk920J+kB7wUUiRpXcmsk+vqd25TcKySV/ZqQmLc4 5HwUlYCLRb16b/a/DChhfQCK/i4d3bP3hD4yr9tk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388453AbfCVMpk (ORCPT ); Fri, 22 Mar 2019 08:45:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:37384 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387725AbfCVMAQ (ORCPT ); Fri, 22 Mar 2019 08:00:16 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 77DEF21934; Fri, 22 Mar 2019 12:00:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553256016; bh=sBJrwuKBclQrBq3lXjS0PqgDZrDahtN5SSz1wa6yTas=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nSMtL46UPP22rCorN45aFmsCe5ZzaNK2n/Jf5C/IkJ9O4v2gg7tNmFdNeu5H8nuvV LvhveuhZXW2Chuqxe1w07IGls4h7qLadQdF0pugEaN6tjRdVwglID8ykGqjKhl/zU3 a3gkfVzIc/7hcNPKdI5Qagd/RoD+2v6NhoYk5U4E= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sven Van Asbroeck , Dmitry Torokhov , Sven Van Asbroeck , Robin van der Gracht , Miguel Ojeda , Sasha Levin Subject: [PATCH 4.19 065/280] auxdisplay: ht16k33: fix potential user-after-free on module unload Date: Fri, 22 Mar 2019 12:13:38 +0100 Message-Id: <20190322111309.941014563@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190322111306.356185024@linuxfoundation.org> References: <20190322111306.356185024@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 69ef9bc54715fb1cb7786ada15774e469e822209 ] On module unload/remove, we need to ensure that work does not run after we have freed resources. Concretely, cancel_delayed_work() may return while the callback function is still running. >>From kernel/workqueue.c: The work callback function may still be running on return, unless it returns true and the work doesn't re-arm itself. Explicitly flush or use cancel_delayed_work_sync() to wait on it. Link: https://lore.kernel.org/lkml/20190204220952.30761-1-TheSven73@googlemail.com/ Reported-by: Sven Van Asbroeck Reviewed-by: Dmitry Torokhov Reviewed-by: Sven Van Asbroeck Acked-by: Robin van der Gracht Signed-off-by: Miguel Ojeda Signed-off-by: Sasha Levin --- drivers/auxdisplay/ht16k33.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/auxdisplay/ht16k33.c b/drivers/auxdisplay/ht16k33.c index a43276c76fc6..21393ec3b9a4 100644 --- a/drivers/auxdisplay/ht16k33.c +++ b/drivers/auxdisplay/ht16k33.c @@ -509,7 +509,7 @@ static int ht16k33_remove(struct i2c_client *client) struct ht16k33_priv *priv = i2c_get_clientdata(client); struct ht16k33_fbdev *fbdev = &priv->fbdev; - cancel_delayed_work(&fbdev->work); + cancel_delayed_work_sync(&fbdev->work); unregister_framebuffer(fbdev->info); framebuffer_release(fbdev->info); free_page((unsigned long) fbdev->buffer); -- 2.19.1