From patchwork Mon Jun 30 09:32:00 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michal Kazior X-Patchwork-Id: 4446961 Return-Path: X-Original-To: patchwork-linux-wireless@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 86AE49F319 for ; Mon, 30 Jun 2014 09:40:27 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id A76A5202FE for ; Mon, 30 Jun 2014 09:40:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 52AC9201DD for ; Mon, 30 Jun 2014 09:40:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755047AbaF3JkX (ORCPT ); Mon, 30 Jun 2014 05:40:23 -0400 Received: from mail-wi0-f176.google.com ([209.85.212.176]:60281 "EHLO mail-wi0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754665AbaF3JkW (ORCPT ); Mon, 30 Jun 2014 05:40:22 -0400 Received: by mail-wi0-f176.google.com with SMTP id n3so5691431wiv.15 for ; Mon, 30 Jun 2014 02:40:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tieto.com; s=google; h=from:to:cc:subject:date:message-id; bh=RMoERyYPQtB3nF1P2ahqLbY/lYMxg8RmeEc9dbsl46U=; b=Nom7re8WNOS/MzY0A9v6kyTkNxBaP6fCY2MI7g4OkPSDuHW/2pl3NfNSZy1bBeOVM3 bj7BIs5AxW+MRTTcGQ4KP07O1FtxkpZnPD7tO6pp6iBYRbXzrKYbgdhoXjiQoqPXdrgy HF+lN8RIJQikjSKn+cVk5KCBUGDyAhRw7VHeY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=RMoERyYPQtB3nF1P2ahqLbY/lYMxg8RmeEc9dbsl46U=; b=CpJ3v4+OezdmsD6G4Onyt6wmHbosYyIJUK5+/RM05bXDtyCDTSaRI00h6KXF7LhEYt 9VdwEahx3Tq/MTalna0QN69l/CC/WouoPJrkDKXcwT56Zhf7f8cWl/3KcGrMpvmHT5uH O578vUOdaEbzOzFrCYNK2XlP8cllrjULmgFFocUaeFqglPBAidMW/h9CdwCB9S6UHVFy Zamc56B7afoKE0G33KxE2UsvjiwAUH5D4O7EnAvgt0z9iHQNnJ1HwPMqmyonI23XhE5k x5/K5Ljq20Bac5hJFLp8/b1cO3OIErwK6BTqIOFTBbJdQDme9cDzj19OZ/KF94V3rsB5 FiSA== X-Gm-Message-State: ALoCoQkn4Js05mbp/BGy9AUgn7pCL9b0SgURgRSwYKvEGS9GJVTv+Ygd14MsHL2mOmDem131K9r06W93JAcQorAGVfNjvxiKgb4T48MFeCo01KV30u4d/d0= X-Received: by 10.180.188.50 with SMTP id fx18mr28443024wic.76.1404121221202; Mon, 30 Jun 2014 02:40:21 -0700 (PDT) Received: from localhost.localdomain ([91.198.246.8]) by mx.google.com with ESMTPSA id s3sm40170962wje.36.2014.06.30.02.40.20 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 30 Jun 2014 02:40:20 -0700 (PDT) From: Michal Kazior To: ath10k@lists.infradead.org Cc: linux-wireless@vger.kernel.org, Michal Kazior Subject: [PATCH] ath10k: fix unregister deadlock when fw probe fails Date: Mon, 30 Jun 2014 11:32:00 +0200 Message-Id: <1404120720-14649-1-git-send-email-michal.kazior@tieto.com> X-Mailer: git-send-email 1.8.5.3 X-DomainID: tieto.com Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID,T_RP_MATCHES_RCVD,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If firmware probing worker failed it called device_release_driver() which synchronously called remove() pci callback. The callback in turn waited for the worker that called it to finish resulting in a deadlock. Waiting for a completion instead of a worker, like some other drivers do, doesn't seem like the best idea either: Syscall Worker probe_fw() rmmod dev_lock() pci->remove() wait_for_completion() complete_all() device_release_driver() dev_lock() [sleep] free(ar) dev_unlock() [resume] There's no guarantee that Worker upon resuming can still access any data/code of the module. Leaving device bound to a driver is not as harmful as deadlocking so remove the call to device_release_driver() while a proper solution is figured out. Signed-off-by: Michal Kazior --- drivers/net/wireless/ath/ath10k/core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c index 82017f5..b70e443 100644 --- a/drivers/net/wireless/ath/ath10k/core.c +++ b/drivers/net/wireless/ath/ath10k/core.c @@ -984,7 +984,9 @@ err_unregister_mac: err_release_fw: ath10k_core_free_firmware_files(ar); err: - device_release_driver(ar->dev); + /* TODO: It's probably a good idea to release device from the driver + * but calling device_release_driver() here will cause a deadlock. + */ return; }