From: Tejun Heo <tj@kernel.org>
To: Edward Adam Davis <eadavis@qq.com>
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
Date: Sat, 11 Apr 2026 10:40:13 -1000 [thread overview]
Message-ID: <adqxrX8Huq1J4BLG@slm.duckdns.org> (raw)
In-Reply-To: <tencent_157925F8BA70BB65336B9E831B714BA11B08@qq.com>
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
next prev parent reply other threads:[~2026-04-11 20:40 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-09 10:04 [syzbot] [cgroups?] KASAN: slab-use-after-free Read in pressure_write syzbot
2026-04-10 4:00 ` [PATCH] sched/psi: fix race between file release and pressure write Edward Adam Davis
2026-04-10 9:00 ` Chen Ridong
2026-04-10 9:45 ` Edward Adam Davis
2026-04-10 12:39 ` [PATCH v2] " Edward Adam Davis
2026-04-10 19:14 ` Tejun Heo
2026-04-11 4:25 ` Edward Adam Davis
2026-04-11 7:39 ` Tejun Heo
2026-04-11 8:29 ` Edward Adam Davis
2026-04-11 20:40 ` Tejun Heo [this message]
2026-04-12 2:32 ` Edward Adam Davis
2026-04-12 2:47 ` [PATCH v3] " Edward Adam Davis
2026-04-13 1:51 ` [PATCH v2] " Chen Ridong
2026-04-13 2:11 ` Edward Adam Davis
2026-04-13 2:44 ` [PATCH v4] " Edward Adam Davis
2026-04-14 2:29 ` Chen Ridong
2026-04-14 4:08 ` Edward Adam Davis
2026-04-14 6:15 ` [PATCH v5] " Edward Adam Davis
2026-04-15 0:48 ` Chen Ridong
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