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From: Tejun Heo <tj@kernel.org>
To: Tadeusz Struk <tadeusz.struk@linaro.org>
Cc: "Michal Koutný" <mkoutny@suse.com>,
	"Hillf Danton" <hdanton@sina.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	syzbot+e42ae441c3b10acf9e9d@syzkaller.appspotmail.com
Subject: Re: [PATCH] cgroup: don't queue css_release_work if one already pending
Date: Mon, 23 May 2022 09:02:01 -1000	[thread overview]
Message-ID: <YovaKZV7IzQgCo9E@slm.duckdns.org> (raw)
In-Reply-To: <6ac66e89-2063-c5e8-df15-f77b76befc05@linaro.org>

On Mon, May 23, 2022 at 12:00:06PM -0700, Tadeusz Struk wrote:
> On 5/20/22 09:42, Michal Koutný wrote:
> > On Fri, May 20, 2022 at 09:38:12AM -0700, Tadeusz Struk <tadeusz.struk@linaro.org> wrote:
> > > as this is a result of enqueuing the same css->destroy_work onto the same WQ,
> > > one on the rcu path and one on the css_release path.
> > > I will prototype it today and test with syzbot.
> > 
> > In my understanding, you'd need two independent work_structs in a css,
> > not two separate workqueues to put the single entry on.
> 
> Yes, separating the css_killed_ref and css_release paths with two separate work_structs
> fixes the two syzbot list corruption issues [1]&[2].
> I tested it on mainline v5.18.0 and v5.10.117
> In case of [2] the mainline triggers an issue, but it is unrelated to list corruption.

Can you try holding an extra ref in the killed path?

Thanks.

-- 
tejun

  reply	other threads:[~2022-05-23 19:23 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-12 19:24 Tadeusz Struk
2022-04-14 16:44 ` Michal Koutný
2022-04-14 17:51   ` Tadeusz Struk
2022-04-21 23:43     ` Tejun Heo
2022-04-22  0:00   ` Tejun Heo
2022-04-22 11:05     ` Michal Koutný
2022-05-18 16:48       ` Tadeusz Struk
     [not found]       ` <20220519112319.2455-1-hdanton@sina.com>
2022-05-19 23:26         ` Tadeusz Struk
2022-05-20  8:13           ` Tejun Heo
2022-05-20 16:38             ` Tadeusz Struk
2022-05-20 16:42               ` Michal Koutný
2022-05-20 16:56                 ` Tadeusz Struk
2022-05-23 19:00                 ` Tadeusz Struk
2022-05-23 19:02                   ` Tejun Heo [this message]
2022-05-23 19:08                     ` Tadeusz Struk
2022-05-23 20:05                       ` Tadeusz Struk
2022-05-23 21:27 ` [PATCH v2] cgroups: separate destroy_work into two separate wq Tadeusz Struk
     [not found] <20220413095606.1182-1-hdanton@sina.com>
2022-04-13 15:39 ` [PATCH] cgroup: don't queue css_release_work if one already pending Tadeusz Struk

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