Received-SPF: pass (google.com: domain of linux-kernel+bounces-43182-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
Sender: Tejun Heo <htejun@gmail.com>
Date: Mon, 29 Jan 2024 07:06:46 -1000
From: Tejun Heo <tj@kernel.org>
To: Allen <allen.lkml@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Mikulas Patocka <mpatocka@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>, linux-kernel@vger.kernel.org,
	dm-devel@lists.linux.dev, Mike Snitzer <msnitzer@redhat.com>,
	Ignat Korchagin <ignat@cloudflare.com>,
	Damien Le Moal <damien.lemoal@wdc.com>,
	Bob Liu <bob.liu@oracle.com>, Hou Tao <houtao1@huawei.com>,
	Nathan Huckleberry <nhuck@google.com>,
	Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH] softirq: fix memory corruption when freeing
 tasklet_struct
Message-ID: <ZbfbJuRRklWhYk4Q@slm.duckdns.org>
References: <82b964f0-c2c8-a2c6-5b1f-f3145dc2c8e5@redhat.com>
 <CAHk-=wjDW53w4-YcSmgKC5RruiRLHmJ1sXeYdp_ZgVoBw=5byA@mail.gmail.com>
 <ZbRDnSyiSE93puQL@slm.duckdns.org>
 <CAOMdWSK5CfVpvwmCxCtYLJ-Qt+ZwhETF3K+AhNcBGtEpkKvFqg@mail.gmail.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAOMdWSK5CfVpvwmCxCtYLJ-Qt+ZwhETF3K+AhNcBGtEpkKvFqg@mail.gmail.com>

Hello,

On Mon, Jan 29, 2024 at 09:00:38AM -0800, Allen wrote:
>     I rushed to reply to the draft patch you sent, I should have
> looked harder. My apologies.
> The idea that I have been working on is to completely move away from
> using tasklets.
> Essentially, "get rid of tasklets entirely in the kernel". So, the use
> of tasklet_schedule() & tasklet_hi_schedule()
> will have to go.

The idea is to take over the tasklet[_hi] softirqs once all users are
converted. Otherwise, we run into the problem of setting priorities between
tasklets and the atomic workqueue, which may be a theoretical problem.

>    I have a very hacky draft that is still wip. I am going to borrow
> many bits from your patch which makes
> the work I have better.
> 
>   Perhaps we should start a separate thread, thoughts?

Sure, please go ahead.

Thanks.

-- 
tejun