From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 01E471422C4; Thu, 11 Apr 2024 10:03:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712829838; cv=none; b=oEgTYzexDfJxSoFNi1cXY2rLQol9dd/ltp362XXlv9M/msoupsLJOX0TbyVIKJKxRJtARx1SElbbvkXeeUA4TZ6TDIuaNSAvdvtX6+cTOlbc242WQfNmaP54qw6Aeg6mjE2d9LPW43jU0cWd/E+abyQ7rtsRFmihi5rp0H3va2I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712829838; c=relaxed/simple; bh=Smlr/XAt+0Y+PE8041GPeWkpFafOAdIknsQmO4/CQLQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hnzsDAZH+dvS5TNDRdGHCSRxQ5N8xPfHUIXJFigOrF8DybScXdxcPEOTQUJ33H7JOFBODN6CI6DguBUrJybSortEV5ntZSvhsiamx1DAyxrNguo7phuGfzWenOuAKhw1X97K2/wfIK2+hmxYnOWuTQNEy22nnqCMNye/qGLgc1w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=wbjkKfnG; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="wbjkKfnG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7C97DC433C7; Thu, 11 Apr 2024 10:03:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1712829837; bh=Smlr/XAt+0Y+PE8041GPeWkpFafOAdIknsQmO4/CQLQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wbjkKfnGvh/i+M91IOU49oR0yAc5MQpdZzeR+a7aD5F2QQd7AbQjLKfb6bpSbTrjK Fqu9uykOB5yhZcE/cc+4YgQYCu/1Qnj1ugHDpdc6xRPYBAm0WVZtVOfKHM3gDPXwMU I1a4LHVkfUS8fWVzJ3kguVfUw9hJRqASf1pCR1eM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable , Oliver Neukum Subject: [PATCH 4.19 084/175] usb: cdc-wdm: close race between read and workqueue Date: Thu, 11 Apr 2024 11:55:07 +0200 Message-ID: <20240411095422.091282703@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240411095419.532012976@linuxfoundation.org> References: <20240411095419.532012976@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Oliver Neukum commit 339f83612f3a569b194680768b22bf113c26a29d upstream. wdm_read() cannot race with itself. However, in service_outstanding_interrupt() it can race with the workqueue, which can be triggered by error handling. Hence we need to make sure that the WDM_RESPONDING flag is not just only set but tested. Fixes: afba937e540c9 ("USB: CDC WDM driver") Cc: stable Signed-off-by: Oliver Neukum Link: https://lore.kernel.org/r/20240314115132.3907-1-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-wdm.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/drivers/usb/class/cdc-wdm.c +++ b/drivers/usb/class/cdc-wdm.c @@ -471,6 +471,7 @@ out_free_mem: static int service_outstanding_interrupt(struct wdm_device *desc) { int rv = 0; + int used; /* submit read urb only if the device is waiting for it */ if (!desc->resp_count || !--desc->resp_count) @@ -485,7 +486,10 @@ static int service_outstanding_interrupt goto out; } - set_bit(WDM_RESPONDING, &desc->flags); + used = test_and_set_bit(WDM_RESPONDING, &desc->flags); + if (used) + goto out; + spin_unlock_irq(&desc->iuspin); rv = usb_submit_urb(desc->response, GFP_KERNEL); spin_lock_irq(&desc->iuspin);