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 3AF1739F195 for ; Wed, 22 Apr 2026 11:52:21 +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=1776858742; cv=none; b=ANf00Y5coku/6ESFd8ZBa89qcX4qpm5lra0drpDO8a3KeBZNJ41L9ZhCO/efOmgTgQYnhvT1WDiJKR6BA3IYoc0zsw3WhG8LiNf5QyhQiEhE3WvukjQ3HysdwgIUPsaBGH4HUoEu6UwMPRWWbICgdVbqJs9hqlNdOAIZKz8rRIQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776858742; c=relaxed/simple; bh=xXNVjLJnxA5ctzr66hLD9pvt1MT5h44wePN81QXSul8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JdLt1W6gJdd8aqanNedZxUGwMlViCwIads5q+7uLoOGL72ohrMMxXpmjg5e6CB153Cp2j5Ytx2ulEn04BJ6/lCsUhxBUOn8J8tEQ5LWsM9hF/EBPW5Op+pMqW9PCQFsHQYE1dhzvDzgcQfjTbzSsZ/xEFQQZJ8KKDOCODp9f2ac= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=YScOEbYb; 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="YScOEbYb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75585C19425; Wed, 22 Apr 2026 11:52:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776858741; bh=xXNVjLJnxA5ctzr66hLD9pvt1MT5h44wePN81QXSul8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YScOEbYbXwtLlT5wQ0hZ5a3omixzqBBIJIJyJ1NOYwXjNVfZ6GTmNVvy0sJQQsoXI yr08UFUPxypuuhZX3yCM6ktjPFwMKRTEtQLNxSAY+bjg5ItpxdbCY9VWKgzDceJlSD 6Pm+/eMnUXeFLe/I/Xj7gGYT0L/jtCF51+MrD6ts= Date: Wed, 22 Apr 2026 13:52:19 +0200 From: Greg KH To: Li Zao Cc: mcgrof@kernel.org, russ.weight@linux.dev, rafael@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] drivers: firmware_loader: fix race between sysfs fallback cleanup and device removal Message-ID: <2026042251-sanding-wing-36dc@gregkh> References: <20260421135013.36322-1-l1za0.sec@gmail.com> <2026042116-matrix-shield-01dd@gregkh> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed, Apr 22, 2026 at 07:36:15PM +0800, Li Zao wrote: > In the report, I saw: > > sysfs group 'power' not found for kobject 'ueagle-atm!eagleI.fw' > WARNING: CPU: 0 PID: 14408 at fs/sysfs/group.c:282 sysfs_remove_group > fs/sysfs/group.c:282 [inline] > WARNING: CPU: 0 PID: 14408 at fs/sysfs/group.c:282 > sysfs_remove_group+0x159/0x1b0 fs/sysfs/group.c:273 > > The reproducer mainly runs an infinite loop(), which continuously forks > and executes execute_one() within loop(). execute_one() constructs > parameters and calls syz_usb_connect(), causing a large number of > connect and disconnect calls. Of a fake USB atm device, right? ATM USB devices are crazy, if you have the rights to make/destroy lots of them like this, you are running as root, and can do worse things :) Luckily ATM is about to be dropped from the kernel, so all is good... > According to the call trace, this problem is triggered when > firmware_fallback_sysfs() calls device_del(). So I suppose the problem > is likely caused by a large number of connect/disconnect operations > triggering some kind of race condition, leading to the device being > unregistered and ultimately causing sysfs_remove_group() to remove > an object that no longer exists. But to be honest, since I'm not very > familiar with this code, I can't be 100% sure. Sorry for my lack of rigor. I'd dig into the ueagle driver and see exactly what it is trying to do with the firmware loading path there, that's probably the issue here, not in the firmware core. thanks, greg k-h