From patchwork Thu Aug 10 00:53:48 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sishuai Gong X-Patchwork-Id: 712473 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 68FF4C0015E for ; Thu, 10 Aug 2023 00:54:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229733AbjHJAyB (ORCPT ); Wed, 9 Aug 2023 20:54:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51556 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229709AbjHJAyB (ORCPT ); Wed, 9 Aug 2023 20:54:01 -0400 Received: from mail-io1-xd36.google.com (mail-io1-xd36.google.com [IPv6:2607:f8b0:4864:20::d36]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A7948F5 for ; Wed, 9 Aug 2023 17:54:00 -0700 (PDT) Received: by mail-io1-xd36.google.com with SMTP id ca18e2360f4ac-79095499a17so13103739f.3 for ; Wed, 09 Aug 2023 17:54:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1691628840; x=1692233640; h=to:cc:date:message-id:subject:mime-version :content-transfer-encoding:from:from:to:cc:subject:date:message-id :reply-to; bh=+Wdkzj6p3rOK19FTNdQYtbs5FYuyIuVaMEM34fKjnrw=; b=cIzA+RQ5GYT9m8eHdPBnG5Xb1kdLF7gc0cro+p9hEUnwS9VoYa+qwJrGruNF28IOGl NqXwp/hHXXJlvU2vvqnHXqkzemmmUG1ixzGuYmoTxG1hu930+XK6bo8AuJe7EysOAgcY BpK4mHTcKCjg5gXTLPAY1EsMTF1ebzmlUnT2PQlQcErNuwgChn3iBc0yJa4ZL4fFtwUx e7tpQNGZLOFgsmecmyhWQsb7fOgczdl9vKFCHrFOGk21tUyZgSFAYQDmToRXlTyEoaFV 6Tp0/vCIj9rrw83yqZ8j+KsMZaUTrOqWSUdxhcUIiCTtbNg0PH5DCk6DVNxTW/RtFIGe I6vw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691628840; x=1692233640; h=to:cc:date:message-id:subject:mime-version :content-transfer-encoding:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=+Wdkzj6p3rOK19FTNdQYtbs5FYuyIuVaMEM34fKjnrw=; b=VQbLE2Tz9YcPW22Z/8LsAmQ6xZxnhlpND1EFIzA0OmiZ8sAwKsAmjhWnc/e1QP6ZFU djR/UsOKjbW/IiQfaLmD/PSB3AEg6Emh2m7Qcyn1EQZd4zHusKuEntV5dMJttZF7oLcx reP+OZYcDZg01WFWQz/jQNjwdIb71MUCSquFuO24xpFt0VIwHUDQIMQK+fKWVMyssIEi gMup7WIC8qoWV33bxenZWOZCHRMTPswQgWr8/Qf3eLW5gX6kH0Yxh5sW+QnBmphmD5Ma 76DpGaRnnm/bRg3RiAw1YyJUU4XVgI8JKcu9z7FQ8t1/HGNUDcdF9lGZLFzhzbW9uuYp r0rg== X-Gm-Message-State: AOJu0YzVLOYQcCvs9GOz0ezImsG0UMdD7E3QZJcZrzBlPE/24zarhflN Ww3dxN/xmEv0JgN9kMMH8rukfgPKw2h6Z3wZ X-Google-Smtp-Source: AGHT+IHxMC3OGJc3+b4jFSQSwvOvIxZ6B3nqToTMwFj447QAXRRd1IxIRqngUfD9WMEYcrNu0jXfJg== X-Received: by 2002:a5e:8907:0:b0:786:7100:72de with SMTP id k7-20020a5e8907000000b00786710072demr1395441ioj.16.1691628839859; Wed, 09 Aug 2023 17:53:59 -0700 (PDT) Received: from smtpclient.apple ([195.252.220.43]) by smtp.gmail.com with ESMTPSA id y8-20020a6be508000000b007836e9ff198sm115417ioc.55.2023.08.09.17.53.59 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 09 Aug 2023 17:53:59 -0700 (PDT) From: Sishuai Gong Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3731.700.6\)) Subject: [PATCH] media: vivid: fix the racy dev->radio_tx_rds_owner Message-Id: Date: Wed, 9 Aug 2023 20:53:48 -0400 Cc: linux-media@vger.kernel.org To: hverkuil@xs4all.nl, mchehab@kernel.org X-Mailer: Apple Mail (2.3731.700.6) Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org There is a race over dev->radio_tx_rds_owner between the two functions mentioned below: Thread-1 Thread-2 vivid_fop_release() vivid_radio_rx_read() mutex_unlock(&dev->mutex) mutex_lock_interruptible(&dev->mutex) ... dev->radio_rx_rds_owner = file->private_data; ... if (file->private_data == dev->radio_rx_rds_owner) { dev->radio_tx_rds_last_block = 0; dev->radio_tx_rds_owner = NULL; } This race can be fixed by only releasing the lock after vivid_fop_release() finishes the checks. Signed-off-by: Sishuai Gong --- drivers/media/test-drivers/vivid/vivid-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/media/test-drivers/vivid/vivid-core.c b/drivers/media/test-drivers/vivid/vivid-core.c index c2167ccfd222..e95bdccfc18e 100644 --- a/drivers/media/test-drivers/vivid/vivid-core.c +++ b/drivers/media/test-drivers/vivid/vivid-core.c @@ -628,7 +628,6 @@ static int vivid_fop_release(struct file *file) v4l2_info(&dev->v4l2_dev, "reconnect\n"); vivid_reconnect(dev); } - mutex_unlock(&dev->mutex); if (file->private_data == dev->radio_rx_rds_owner) { dev->radio_rx_rds_last_block = 0; dev->radio_rx_rds_owner = NULL; @@ -637,6 +636,7 @@ static int vivid_fop_release(struct file *file) dev->radio_tx_rds_last_block = 0; dev->radio_tx_rds_owner = NULL; } + mutex_unlock(&dev->mutex); if (vdev->queue) return vb2_fop_release(file); return v4l2_fh_release(file);