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 Received: from smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D60CCC4332F for ; Fri, 3 Nov 2023 18:36:43 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 7C16F40944; Fri, 3 Nov 2023 18:36:43 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org 7C16F40944 Authentication-Results: smtp4.osuosl.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=VU/FOCJ/ X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id T3m9o12YPPUv; Fri, 3 Nov 2023 18:36:40 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp4.osuosl.org (Postfix) with ESMTPS id B5BEF408F0; Fri, 3 Nov 2023 18:36:39 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org B5BEF408F0 Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 79E73C0071; Fri, 3 Nov 2023 18:36:39 +0000 (UTC) Received: from smtp1.osuosl.org (smtp1.osuosl.org [IPv6:2605:bc80:3010::138]) by lists.linuxfoundation.org (Postfix) with ESMTP id 4FA8CC0032 for ; Fri, 3 Nov 2023 18:36:38 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id 1E5C281992 for ; Fri, 3 Nov 2023 18:36:38 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp1.osuosl.org 1E5C281992 Authentication-Results: smtp1.osuosl.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=VU/FOCJ/ X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 01F0Nv4igy_1 for ; Fri, 3 Nov 2023 18:36:32 +0000 (UTC) Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by smtp1.osuosl.org (Postfix) with ESMTPS id 734DA817B3 for ; Fri, 3 Nov 2023 18:36:32 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp1.osuosl.org 734DA817B3 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id 1D2F7CE1670; Fri, 3 Nov 2023 18:36:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C2D3DC433C9; Fri, 3 Nov 2023 18:36:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1699036589; bh=t9OfWxjmRBsqiXsPbyw2EcQvdxCl+LfcMDqz160D6P0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=VU/FOCJ/cTCilDbfiLeOP72tgqUIXdMSVGR+Ke5guOy/o/T/rbXj1FufplOpovd+w Itxd0lOZTAw1wvsRc9+8rylrt0HhsOmJY6QfDgh+OjdSGr6t4EBqGkhhDCqM8tmeme mDRNr1NzPYZtZ4Sg7B5sdiVLT0UnDsz90WxQ6vXs= Date: Fri, 3 Nov 2023 19:36:21 +0100 From: Greg KH To: =?iso-8859-1?Q?Jos=E9?= Pekkarinen Subject: Re: [PATCH] drivers core: lookup sysfs power group before removal Message-ID: <2023110353-bring-contented-c9f8@gregkh> References: <20231101173627.2658-1-jose.pekkarinen@foxhound.fi> <2023110139-dupe-snipping-5700@gregkh> <835b2930c710381b8da38eca821aa92d@foxhound.fi> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <835b2930c710381b8da38eca821aa92d@foxhound.fi> Cc: len.brown@intel.com, linux-pm@vger.kernel.org, rafael@kernel.org, linux-kernel@vger.kernel.org, syzbot+95f2e2439b97575ec3c0@syzkaller.appspotmail.com, pavel@ucw.cz, linux-kernel-mentees@lists.linuxfoundation.org X-BeenThere: linux-kernel-mentees@lists.linuxfoundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Errors-To: linux-kernel-mentees-bounces@lists.linuxfoundation.org Sender: "Linux-kernel-mentees" On Fri, Nov 03, 2023 at 07:49:39PM +0200, Jos=E9 Pekkarinen wrote: > On 2023-11-01 19:54, Greg KH wrote: > > On Wed, Nov 01, 2023 at 07:36:27PM +0200, Jos=E9 Pekkarinen wrote: > > > Hinted by syzboot, there is a few cases where the sysfs power group > > > may > > > not be there, like the failure while adding it, or adding its runtime > > > group, or when the sysfs firmware loader fallback fail to populate. In > > > the last case, the device_del function will be called leading to > > > attempt > > > to remove the sysfs group. This patch will lookup for it in advance to > > > grant that it is effectively there before cleaning it up. > > > = > > > Reported-by: syzbot+95f2e2439b97575ec3c0@syzkaller.appspotmail.com > > > = > > > Signed-off-by: Jos=E9 Pekkarinen > > > --- > > > drivers/base/power/sysfs.c | 4 +++- > > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > = > > > diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c > > > index a1474fb67db9..6601729c4698 100644 > > > --- a/drivers/base/power/sysfs.c > > > +++ b/drivers/base/power/sysfs.c > > > @@ -834,5 +834,7 @@ void dpm_sysfs_remove(struct device *dev) > > > dev_pm_qos_constraints_destroy(dev); > > > rpm_sysfs_remove(dev); > > > sysfs_unmerge_group(&dev->kobj, &pm_wakeup_attr_group); > > > - sysfs_remove_group(&dev->kobj, &pm_attr_group); > > > + > > > + if (kernfs_find_and_get((&dev->kobj)->sd, pm_attr_group.name)) > > > + sysfs_remove_group(&dev->kobj, &pm_attr_group); > > = > > What's to keep it from going away right after finding it? > > = > > In other words, what is wrong with removing a group that is not there? > > What error happens? It should be fine, or are you seeing real code > > failures somewhere? > = > No, this is just hitting a warning that sysbot complains about by > setting panic on warning, no big deal, though it can be a wrong behaviour > in ueagle-atm driver, since it defines to disconnect the device if the > firmware is not there, no matter the sysfs fallback. Then fix the driver please. And what warning are you seeing exactly? thanks, greg k-h _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees