From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C3DC2C433E3 for ; Mon, 17 Aug 2020 19:15:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A9B00204EC for ; Mon, 17 Aug 2020 19:15:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597691759; bh=R0QLPaEn5SylRjQHBNE7hrmwe2DVacujRcor1yz0pyM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=w9omL6nXnV3tF/aF0q6DI3gpR62jvSgRIneYpfXJH4UG7wJOCtBOfyw7mSSIt8fz/ ITfugKcGZi+yi+6G0Mmkt+KEfrN/lFouZ7/OMv+wHRHsu4YzPP2IQcldvzLA9mzQGQ //RaOd2n4+Y7cesSZEEmjS2PZLCcowXx1RD7jukQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390083AbgHQTP6 (ORCPT ); Mon, 17 Aug 2020 15:15:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:48264 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387450AbgHQPjl (ORCPT ); Mon, 17 Aug 2020 11:39:41 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 539BD22DD6; Mon, 17 Aug 2020 15:39:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597678781; bh=R0QLPaEn5SylRjQHBNE7hrmwe2DVacujRcor1yz0pyM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jd+Lx8E8E9QhZVK0arLoM2+AbIyytMhBlPgELyQSGN6gAWiKhzQahYNVnkkg0uJwy cS2fFQDyZDUNkO+eXfseJCwO2444mi4lWuHPRh1Awr/XOl742J7wtevvLc1pkwB5aP MTDGqBl252oluPx8f2PNq03vUGop1lTwyXj38Vac= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot , Geert Uytterhoeven , Tetsuo Handa , stable Subject: [PATCH 5.8 421/464] driver core: Fix probe_count imbalance in really_probe() Date: Mon, 17 Aug 2020 17:16:14 +0200 Message-Id: <20200817143853.941082307@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200817143833.737102804@linuxfoundation.org> References: <20200817143833.737102804@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tetsuo Handa commit b292b50b0efcc7095d8bf15505fba6909bb35dce upstream. syzbot is reporting hung task in wait_for_device_probe() [1]. At least, we always need to decrement probe_count if we incremented probe_count in really_probe(). However, since I can't find "Resources present before probing" message in the console log, both "this message simply flowed off" and "syzbot is not hitting this path" will be possible. Therefore, while we are at it, let's also prepare for concurrent wait_for_device_probe() calls by replacing wake_up() with wake_up_all(). [1] https://syzkaller.appspot.com/bug?id=25c833f1983c9c1d512f4ff860dd0d7f5a2e2c0f Reported-by: syzbot Fixes: 7c35e699c88bd607 ("driver core: Print device when resources present in really_probe()") Cc: Geert Uytterhoeven Signed-off-by: Tetsuo Handa Cc: stable Link: https://lore.kernel.org/r/20200713021254.3444-1-penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Greg Kroah-Hartman --- drivers/base/dd.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -276,7 +276,7 @@ static void deferred_probe_timeout_work_ list_for_each_entry_safe(private, p, &deferred_probe_pending_list, deferred_probe) dev_info(private->device, "deferred probe pending\n"); - wake_up(&probe_timeout_waitqueue); + wake_up_all(&probe_timeout_waitqueue); } static DECLARE_DELAYED_WORK(deferred_probe_timeout_work, deferred_probe_timeout_work_func); @@ -487,7 +487,8 @@ static int really_probe(struct device *d drv->bus->name, __func__, drv->name, dev_name(dev)); if (!list_empty(&dev->devres_head)) { dev_crit(dev, "Resources present before probing\n"); - return -EBUSY; + ret = -EBUSY; + goto done; } re_probe: @@ -607,7 +608,7 @@ pinctrl_bind_failed: ret = 0; done: atomic_dec(&probe_count); - wake_up(&probe_waitqueue); + wake_up_all(&probe_waitqueue); return ret; }