From patchwork Fri Jan 14 13:33:31 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jann Horn X-Patchwork-Id: 12713631 X-Patchwork-Delegate: jikos@jikos.cz Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6416AC433F5 for ; Fri, 14 Jan 2022 13:33:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241304AbiANNd4 (ORCPT ); Fri, 14 Jan 2022 08:33:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37150 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241295AbiANNd4 (ORCPT ); Fri, 14 Jan 2022 08:33:56 -0500 Received: from mail-wr1-x431.google.com (mail-wr1-x431.google.com [IPv6:2a00:1450:4864:20::431]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D5332C06161C for ; Fri, 14 Jan 2022 05:33:55 -0800 (PST) Received: by mail-wr1-x431.google.com with SMTP id d19so15765764wrb.0 for ; Fri, 14 Jan 2022 05:33:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=1vFopuQifYDi+69/YOS3FtXomAJ3p0gkydigw8chDQ0=; b=a5nSqjObrDQ4Lo5GFtrtp+8nCr/2mklxVAwYpc7l6aCVBZGicECk12JIbC8o+5Rf5C XzDskzu8LlkCMd3/YIecElTiR4Y47JQ7zW9yV4Hfcyuq0NETzHKLrDu1+ijSMDkZHt0J +e5xS2ALfYktsaGRBoowlUpepwWml4fMEWk8Tc/hqzJWvkIi8XeGC7h60k+4gA9Q5muW c7hkWMQoyucp1mz7uiPYA3QSaNPQo2+ODe/+GkdfIGP98V6uF3cOZ0sAd2WYSUCmW1GI 6EvqEaz1lZUJrTMKIBLF6edt9Av4SsPGZmIXPPYjiMIid0fVTtxgi2NSAn2iI3i90bqh VY0Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=1vFopuQifYDi+69/YOS3FtXomAJ3p0gkydigw8chDQ0=; b=Jxz+IMOlGP+EkWegwizzQp4GYVMy/dC+WMGWz0mEqm7vNroGKU4dIkjBfHFiJ3VuFm WPVNWv2AahqrbfJSN/62D9y5r5WBTGOoqiRPWt4WiBiAT2H2+0qwI+h79aF32xinFjjS BoB3P6b497SEyByDTqLTNP0oUOij23VFfYQ5CV17lD/gONEJ2Wro5cBu3QYTOZH1PQsK /U8QAhWv4S4Mb19D2pRwSgb7ux9nFPlY9mfAp5pyMXeiM37VR7CdAaILNk/j4sNXLyhM iUTF1iws1FVTruhCuq3r8D5jrTcU3cFl3SVtZGM9/Vtd0cNBG97slHd27g1VZ97pzNDs QheA== X-Gm-Message-State: AOAM533U2D7ufAMM4Jekd0BcoOWpoCI0AMEAklbaT52pxB98Aqz8HsZj AnvZxmx/doMfBfMjnGEV4qXt1w== X-Google-Smtp-Source: ABdhPJwr0xIgD9c24X+iXCLh6Zzcm6rRYn5SEpoc0fHT2awItaqzsdWydUn89R1ptwH+puAG0d1N+g== X-Received: by 2002:adf:fd43:: with SMTP id h3mr8602682wrs.341.1642167234352; Fri, 14 Jan 2022 05:33:54 -0800 (PST) Received: from localhost ([2a02:168:96c5:1:55ed:514f:6ad7:5bcc]) by smtp.gmail.com with ESMTPSA id j11sm7381241wmq.23.2022.01.14.05.33.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 14 Jan 2022 05:33:53 -0800 (PST) From: Jann Horn To: David Rheinsberg , Jiri Kosina , Benjamin Tissoires , linux-input@vger.kernel.org Cc: Roderick Colenbrander , linux-kernel@vger.kernel.org, Jann Horn Subject: [PATCH 2/2] HID: uhid: Use READ_ONCE()/WRITE_ONCE() for ->running Date: Fri, 14 Jan 2022 14:33:31 +0100 Message-Id: <20220114133331.873057-2-jannh@google.com> X-Mailer: git-send-email 2.34.1.703.g22d0c6ccf7-goog In-Reply-To: <20220114133331.873057-1-jannh@google.com> References: <20220114133331.873057-1-jannh@google.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org The flag uhid->running can be set to false by uhid_device_add_worker() without holding the uhid->devlock. Mark all reads/writes of the flag that might race with READ_ONCE()/WRITE_ONCE() for clarity and correctness. Signed-off-by: Jann Horn --- Notes: This is just some cleanup to make it clearer what's going on and avoid UB. If you don't want to take this patch, feel free to just take patch 1/2. drivers/hid/uhid.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c index fc06d8bb42e0..614adb510dbd 100644 --- a/drivers/hid/uhid.c +++ b/drivers/hid/uhid.c @@ -84,7 +84,7 @@ static void uhid_device_add_worker(struct work_struct *work) * However, we do have to clear the ->running flag and do a * wakeup to make sure userspace knows that the device is gone. */ - uhid->running = false; + WRITE_ONCE(uhid->running, false); wake_up_interruptible(&uhid->report_wait); } } @@ -194,9 +194,9 @@ static int __uhid_report_queue_and_wait(struct uhid_device *uhid, spin_unlock_irqrestore(&uhid->qlock, flags); ret = wait_event_interruptible_timeout(uhid->report_wait, - !uhid->report_running || !uhid->running, + !uhid->report_running || !READ_ONCE(uhid->running), 5 * HZ); - if (!ret || !uhid->running || uhid->report_running) + if (!ret || !READ_ONCE(uhid->running) || uhid->report_running) ret = -EIO; else if (ret < 0) ret = -ERESTARTSYS; @@ -237,7 +237,7 @@ static int uhid_hid_get_report(struct hid_device *hid, unsigned char rnum, struct uhid_event *ev; int ret; - if (!uhid->running) + if (!READ_ONCE(uhid->running)) return -EIO; ev = kzalloc(sizeof(*ev), GFP_KERNEL); @@ -279,7 +279,7 @@ static int uhid_hid_set_report(struct hid_device *hid, unsigned char rnum, struct uhid_event *ev; int ret; - if (!uhid->running || count > UHID_DATA_MAX) + if (!READ_ONCE(uhid->running) || count > UHID_DATA_MAX) return -EIO; ev = kzalloc(sizeof(*ev), GFP_KERNEL); @@ -579,7 +579,7 @@ static int uhid_dev_destroy(struct uhid_device *uhid) if (!uhid->hid) return -EINVAL; - uhid->running = false; + WRITE_ONCE(uhid->running, false); wake_up_interruptible(&uhid->report_wait); cancel_work_sync(&uhid->worker); @@ -593,7 +593,7 @@ static int uhid_dev_destroy(struct uhid_device *uhid) static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev) { - if (!uhid->running) + if (!READ_ONCE(uhid->running)) return -EINVAL; hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data, @@ -604,7 +604,7 @@ static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev) static int uhid_dev_input2(struct uhid_device *uhid, struct uhid_event *ev) { - if (!uhid->running) + if (!READ_ONCE(uhid->running)) return -EINVAL; hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input2.data, @@ -616,7 +616,7 @@ static int uhid_dev_input2(struct uhid_device *uhid, struct uhid_event *ev) static int uhid_dev_get_report_reply(struct uhid_device *uhid, struct uhid_event *ev) { - if (!uhid->running) + if (!READ_ONCE(uhid->running)) return -EINVAL; uhid_report_wake_up(uhid, ev->u.get_report_reply.id, ev); @@ -626,7 +626,7 @@ static int uhid_dev_get_report_reply(struct uhid_device *uhid, static int uhid_dev_set_report_reply(struct uhid_device *uhid, struct uhid_event *ev) { - if (!uhid->running) + if (!READ_ONCE(uhid->running)) return -EINVAL; uhid_report_wake_up(uhid, ev->u.set_report_reply.id, ev);