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 CE41D33D51B; Fri, 10 Apr 2026 19:14:06 +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=1775848446; cv=none; b=snc6LrG/JENC3ME4r3h2fQ3XDJ6Ovoas9oGG0LHKrw+fdDtAixx47D82SwEpagibDIfBqvAt5oOPyAYdyNr2FmEfgbLlG/hoy5kBH8Ng4Timi3+QzlQjdS5ygN+i8oMnI85DSxkD6DWW6cGf8ivwa1GGrcNtGStcWQ8gQWCaPTY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775848446; c=relaxed/simple; bh=kev1Y9d1IaYRLUIqEs1w6qDnHancs5KYjE9sWMg1L5I=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=rkXyRLgMvY8xnpZr3CxSpWz8/UNAV9f4FnVb3Zc6aKO3P+xU2IE0ZBu/myWRvCnLBM2YvbOZBGId/y9MQy8qWXwsNwqncwchSKgd3GF9aAZ5uiwLopojoNKfrL2qwoOvMnZ8DSQiD8yPKgqVXdE2i6/SfcAKPOOVQHNu3TI2rCQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nytV5s2b; 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="nytV5s2b" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2A4EDC19421; Fri, 10 Apr 2026 19:14:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775848446; bh=kev1Y9d1IaYRLUIqEs1w6qDnHancs5KYjE9sWMg1L5I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nytV5s2biuAZjPjTTovN3EJl1z+4XLWO8NDmDP5WR+k+w123TeeXCVo5ZQi79gWK3 tj6dtQHD4mF5/vW19aJ5s0W7PlanvfGA29lFEwueOJ2Qxbb9q+XJ9YoJ7c3wflOeJs SGvVo6v11CpRFthvh+hk+TLZLb8dFH4MH314K5LjT7BsyhaM1EhktJZ0Hfb6hK4gqp +0LXd3sNs6BmG6/MxwpOe/PbtNLOOY+yGs0YF78J8gnRLZbLPtKB7pqIXZSuP4ZO3w 225PddvEC146EvqQPvkIjjTb9GFtlxa82hz0LG7o110Hs1+YG1qc8i2yEPAwD+lko0 kqaC1YzhL9tfQ== Date: Fri, 10 Apr 2026 09:14:05 -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: cgroups@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 Fri, Apr 10, 2026 at 08:39:45PM +0800, Edward Adam Davis wrote: > static ssize_t pressure_write(struct kernfs_open_file *of, char *buf, > size_t nbytes, enum psi_res res) > { > - struct cgroup_file_ctx *ctx = of->priv; > + struct cgroup_file_ctx *ctx; > struct psi_trigger *new; > struct cgroup *cgrp; > struct psi_group *psi; > + ssize_t ret = 0; > > cgrp = cgroup_kn_lock_live(of->kn, false); > if (!cgrp) > return -ENODEV; > > + ctx = of->priv; > + if (!ctx) { This test likely isn't necessary but that's pre-existing. > + ret = -ENODEV; > + goto out_unlock; > + } > + > cgroup_get(cgrp); We don't need get/put if we don't drop the mutex, right? Thanks. -- tejun