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 6051A2DAFBE; Thu, 4 Dec 2025 11:53:40 +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=1764849220; cv=none; b=fTe5TjrJjUwRXyteTQ2Xux4ik1CSVz7oyPG5tlA4kLmsk1IffrVO8CLFycIKSy0/dbcRLPT6ui9/+2Ar9k9QU9qcw64lclPKfKdsZcVZja01PnbNu2e2QQfI2Out9mq+6bQ45riYpfWpbMei0ZqzzASkcw8PM21enFaV8nW0fp8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764849220; c=relaxed/simple; bh=L3hEC/VBaZaUXv80HCKy07BIxXVcM/EDaXeEIWewJHU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=tRGqVze/mHBTR8aBxC+eSLMAnWZqa8n+c+yUthoMMsKZrp1qYjV4XC82p/q2G6hnfW2c97qdarVCIkU4YSDu/Kccy08Ywv6uof2DDAFmqfI5YTGP1ShY3Wj15yyh1Jn6ORvHzwtq0YlQba9AcrtxCnn4okyZTcWRPglDHVdmnIg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=go/IgpOZ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="go/IgpOZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B38D7C4CEFB; Thu, 4 Dec 2025 11:53:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764849220; bh=L3hEC/VBaZaUXv80HCKy07BIxXVcM/EDaXeEIWewJHU=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=go/IgpOZU8JX2GpIm/zXaX55hQX4XbtrP0pG8ftqcqvnoSuhBQPw9pn4Gjd8SuqJ+ PrYEH51l4d/20+T4KIS2yAH7Td1y0RQ/pMlUiGIzA5SVzPWvK3yqPZwUMafnGVrvFg 7ufiIrfu0RsRb4RzJnavDn3e1ge3N3JKi3tIZdG2MTa4Zz+ItNHAfO5qWbIBvVhuIC vvPd+dJ0UC7LW6yCpuU7Ux/aQg+eLaz4hR8jzEJWPNHbBF3nsAY7x6yg2yGHUshEfT Wtt+2dlunZ1e5p6ZD1gC60Nxdn166cIKIVGKf7HPLA2Qw4xIdbmHm20acWiqVc32gu 8a72lh2JbGzhA== Message-ID: <0fc5c657-4edf-474f-9df7-3c3473b5f458@kernel.org> Date: Thu, 4 Dec 2025 12:53:37 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] reset: gpio: suppress bind attributes in sysfs To: Bartosz Golaszewski Cc: Bartosz Golaszewski , Philipp Zabel , linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20251204094412.17116-1-bartosz.golaszewski@oss.qualcomm.com> <75004da5-1ff6-4391-9839-2d134709eea0@kernel.org> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit On 04/12/2025 12:22, Bartosz Golaszewski wrote: > On Thu, Dec 4, 2025 at 12:14 PM Krzysztof Kozlowski wrote: >> >> On 04/12/2025 10:44, Bartosz Golaszewski wrote: >>> This is a special device that's created dynamically and is supposed to >>> stay in memory forever. We also currently don't have a devlink between >> >> Not forever. If every consumer is unloaded, this can be unloaded too, no? >> >>> it and the actual reset consumer. Suppress sysfs bind attributes so that >> >> With that reasoning every reset consumer should have suppress binds. >> Devlink should be created by reset controller framework so it is not >> this driver's fault. >> > > Here's my reasoning: I will add a devlink but Phillipp requested some > changes so I still need to resend it. It will be a bigger change than > this one-liner. The reset-gpio device was also converted to auxiliary > bus for v6.19 and I will also convert reset core to using fwnodes for > v6.20 so we'll significantly diverge in stable branches, while this > issue is present ever since the reset-gpio driver exists. It's not the > driver's fault but it's easier to fix it here and it very much is a > special case - it's a software based device rammed in between two > firmware-described devices. That's not the answer to my question. You can unbind every other reset controller. Why is this special although maybe you mentioned below? > >> >>> user-space can't unbind the device because - as of now - it will cause a >>> use-after-free splat from any user that puts the reset control handle. >>> >>> Fixes: cee544a40e44 ("reset: gpio: Add GPIO-based reset controller") >> >> Nothing to be fixed here, unless you claim that every reset provider is >> broken as well? What is exactly different in handling devlinks between >> this driver and every other reset provider? >> > > I don't care if we keep the tag, it's just that this commit introduced > a way for user-space to crash the system by simply unbinding > reset-gpio and then its active consumers. > > And the difference here is that there is no devlink between reset-gpio > and its consumers. We need to first agree how to add it. So you mean that between every other reset consumer and reset provider there is a devlink? And here there is no devlink? Best regards, Krzysztof