From patchwork Thu Jan 19 22:40:54 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Torokhov X-Patchwork-Id: 9527053 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id D404B6020B for ; Thu, 19 Jan 2017 22:41:06 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C661D2864F for ; Thu, 19 Jan 2017 22:41:06 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BACFC28670; Thu, 19 Jan 2017 22:41:06 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.3 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, RCVD_IN_SORBS_SPAM, T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 564592864F for ; Thu, 19 Jan 2017 22:41:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753419AbdASWlE (ORCPT ); Thu, 19 Jan 2017 17:41:04 -0500 Received: from mail-pg0-f65.google.com ([74.125.83.65]:36485 "EHLO mail-pg0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753244AbdASWlC (ORCPT ); Thu, 19 Jan 2017 17:41:02 -0500 Received: by mail-pg0-f65.google.com with SMTP id 75so5151362pgf.3; Thu, 19 Jan 2017 14:41:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=fWj2YB27VREznQTvS8Ay5uGmJ9ScZ3rD4G5PXL1aQLo=; b=ZBVD5C2Ax6C0lvrjjoJoE112oM4LlRBOB+ijQ1N0+buj/Tj8504ud9OERM12SPwHsH CTLaVz88Dzz5CzDrjiF1sHIBx2ZCPjTMGIjgFHHZuIQBQwGHei8golfZKG2PHbRhQD8M 6W6nJ/8po6hlUXjyfI261HX7Jyp4sEfvRdC5w+ILw1t70q0vcGnswM64+0sts8GOsy7y tlOeMSC3rWKe8rOj7tlp4tuSHPfkRDV/HIjYAiA/TfPQwWTh01GO0u98mD20zXyJbrwe m5OEzj63vZgdjzEvXBC0OxJrdWQDbN1ahx2i071+z6UVuXwVtHQl9ZCQ2cbf34xEr9nZ Aacw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=fWj2YB27VREznQTvS8Ay5uGmJ9ScZ3rD4G5PXL1aQLo=; b=f7tixNi7F8l2xO6rpf1D9stiuJbsGt2eFZjFL9+VndvhRSztuOsUrRDLLBXF8j6KDh /kLbMKThqNJIwe6iagsrFiTL42qey4acXQjTTVR5YJmqFViGPdjOkq4gpSkxv/cYTKUa /Ynx0knKnkDls5gZ6Qz7Xq+o0e7hwTgGOIZsHeNyfmVQvmA2zfNfSF5xLbC0B0k77ZbE K1RXRFbBeN0kOuTJemSko+KQVlmMOr36subcRqeMuOpl1PBSj3xD67zc2/mx8FxYvxPI Ao0ijVrv0vNmeDeRVzAMdy9IH+hbdLud/4rfMwshMplEcEzYpZ0G9HtZFzXVTz6szjKl oQGw== X-Gm-Message-State: AIkVDXKJGjCCxTsxkACbqNbZYKnwLOPvDwMJcMd+UHEYKoHA+/yQCuckrKHvSSqprXf0TA== X-Received: by 10.99.126.27 with SMTP id z27mr12836277pgc.177.1484865662116; Thu, 19 Jan 2017 14:41:02 -0800 (PST) Received: from dtor-ws.mtv.corp.google.com ([172.22.152.34]) by smtp.gmail.com with ESMTPSA id s136sm11207573pgc.38.2017.01.19.14.41.01 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 19 Jan 2017 14:41:01 -0800 (PST) From: Dmitry Torokhov To: linux-input@vger.kernel.org Cc: Thierry Reding , linux-kernel@vger.kernel.org, David Lechner , Frieder Schrempf Subject: [PATCH v2 4/7] Input: pwm-beeper - fix race when suspending Date: Thu, 19 Jan 2017 14:40:54 -0800 Message-Id: <20170119224057.9995-4-dmitry.torokhov@gmail.com> X-Mailer: git-send-email 2.11.0.483.g087da7b7c-goog In-Reply-To: <20170119224057.9995-1-dmitry.torokhov@gmail.com> References: <20170119224057.9995-1-dmitry.torokhov@gmail.com> Sender: linux-input-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Usually userspace sends SND_BELL and SND_TONE events, and by the time pwm_beeper_suspend() runs userpsace is already frozen, but theoretically in-kernel users may send these events too, and that may cause pwm_beeper_event() scheduling another work after we canceled it. Let's introduce a "suspended" flag and check it in pwm_beeper_event() to avoid this race. Signed-off-by: Dmitry Torokhov Reviewed-by: Thierry Reding --- drivers/input/misc/pwm-beeper.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c index ce6eec48ec5f..04c8ad3827d9 100644 --- a/drivers/input/misc/pwm-beeper.c +++ b/drivers/input/misc/pwm-beeper.c @@ -27,6 +27,7 @@ struct pwm_beeper { struct pwm_device *pwm; struct work_struct work; unsigned long period; + bool suspended; }; #define HZ_TO_NANOSECONDS(x) (1000000000UL/(x)) @@ -73,7 +74,8 @@ static int pwm_beeper_event(struct input_dev *input, else beeper->period = HZ_TO_NANOSECONDS(value); - schedule_work(&beeper->work); + if (!beeper->suspended) + schedule_work(&beeper->work); return 0; } @@ -154,6 +156,15 @@ static int __maybe_unused pwm_beeper_suspend(struct device *dev) { struct pwm_beeper *beeper = dev_get_drvdata(dev); + /* + * Spinlock is taken here is not to protect write to + * beeper->suspended, but to ensure that pwm_beeper_event + * does not re-submit work once flag is set. + */ + spin_lock_irq(&beeper->input->event_lock); + beeper->suspended = true; + spin_unlock_irq(&beeper->input->event_lock); + pwm_beeper_stop(beeper); return 0; @@ -163,8 +174,12 @@ static int __maybe_unused pwm_beeper_resume(struct device *dev) { struct pwm_beeper *beeper = dev_get_drvdata(dev); - if (beeper->period) - __pwm_beeper_set(beeper); + spin_lock_irq(&beeper->input->event_lock); + beeper->suspended = false; + spin_unlock_irq(&beeper->input->event_lock); + + /* Let worker figure out if we should resume beeping */ + schedule_work(&beeper->work); return 0; }