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 6B800175A9C; Sat, 11 Apr 2026 20:40:15 +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=1775940015; cv=none; b=B37DRH0wav9K5fPKEYGyZRvjIEpqvq8XTPVwKnHjTdPByaRToSvVP8Ckc4wsGGnnMeqcsymcYRVTsibtCtb85KGiO6EK7j/Y3y/dFuHWYkSSYXcBKLeAQ2Nrw4W+2emuoq4WnoHSB+PkzaOQYweXEBDgxHEoj4iO3aWqZ3vxv14= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775940015; c=relaxed/simple; bh=gDxz6ztrkLHIlDZTuuR2I8phhWDCINBsHfpF42h2Ki8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=SCrZ265RuDpmzioahqbrZ7HuiywUWJU8g9/CZoxF22hjMGZapHGkG5wVjBZ1Tz8oRXceEerVFIYAXdUkftS/wHlcgDtBxJjX0eGkiGcrYjBnAM7TxSA1S0s5gwpgpEzMedB7cB+RhhOuaGwwjfuZxAW8CNZWlbJ9aTBaq+uam3A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oM0evz2H; 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="oM0evz2H" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E086BC116C6; Sat, 11 Apr 2026 20:40:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775940015; bh=gDxz6ztrkLHIlDZTuuR2I8phhWDCINBsHfpF42h2Ki8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oM0evz2HyYNZZVkHSOvER+5hKLjTvX6zowrHgOOUFnLEyKE7j5QOLOBeCr8GCaqe9 XoVONYFfjNTjgzzEUiacEc+VBtZxetRKCDJ4GIZE6NCPU520acwHa2tj5qZ0alalo+ DtkIZhSRCTgyPaEClTeyrIVEUS6jC27r9Fj1uHlPhyn4m0xXcwSD+Quxv6LSicjjdH flB43DSMrDlp/ieOjDmLRnGg4QsIof3t6U3bfqAe23Mrww6MP/ROMXY1kBUnzuN8sI XVoQeK7T6wkYRZg+810BVoCvZqeT96pmc8myqPXEGiRnoYjeIwsLQxxSzF03klThut m9JxrEw1fxm/Q== Date: Sat, 11 Apr 2026 10:40:13 -1000 From: Tejun Heo To: Edward Adam Davis Cc: cgroups@vger.kernel.org, chenridong@huaweicloud.com, hannes@cmpxchg.org, linux-kernel@vger.kernel.org, mkoutny@suse.com, syzbot+33e571025d88efd1312c@syzkaller.appspotmail.com, syzkaller-bugs@googlegroups.com Subject: Re: [PATCH v2] sched/psi: fix race between file release and pressure write Message-ID: References: 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: Hello, On Sat, Apr 11, 2026 at 04:29:22PM +0800, Edward Adam Davis wrote: > On Fri, 10 Apr 2026 21:39:49 -1000, Tejun Heo wrote: > > > > > + ctx = of->priv; > > > > > + if (!ctx) { > > > > > > > > This test likely isn't necessary but that's pre-existing. > > > Where? > > > Are you referring to the check for of->released within: > > > > No, I'm talking about of->priv. I don't think it can be NULL while a live > > cgroup kn is locked, can it? > > If the lock is acquired before the execution of cgroup_file_release() > completes, it will not be NULL; however, if acquired afterwards, it > will invariably be NULL. Hmmm? While the write is in flight the file can't be released and the cgroup couldn't have been dead if lock_live succeeded. This part is tangential anyway. Let's ignore for now. Thanks. -- tejun