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From: Sven Van Asbroeck <thesven73@gmail.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Kees Cook <keescook@chromium.org>, Tejun Heo <tj@kernel.org>,
	Lai Jiangshan <jiangshanlai@gmail.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Sebastian Reichel <sre@kernel.org>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>
Subject: Re: [RFC v1 0/3] Address potential user-after-free on module unload
Date: Tue, 5 Feb 2019 14:12:31 -0500	[thread overview]
Message-ID: <CAGngYiUMuM_ZxHKVWRihDHZcMncvTwR6Sz1zGNJLrGpyhhT1uQ@mail.gmail.com> (raw)
In-Reply-To: <20190205184355.GC22198@kroah.com>

On Tue, Feb 5, 2019 at 1:43 PM Greg KH <gregkh@linuxfoundation.org> wrote:
>
>
> It really should happen when the device is removed (if it is a driver
> that binds to a device.)

Absolutely. That's why I'm advocating adding a devm_init_work(),
which will take care of this automatically.

But it's of course not universally applicable. Not all drivers use devm.

> If this is not a driver, then there should be
> some way to scan that cancel_work_sync() is never called or not, right?

Are you saying the same thing as Kees, that ideally there should be
infrastructure that WARN()s if work isn't cleaned up properly?

I guess for that to work, the code would need to 'know' what resources
the work function is touching. And warn if one of the resources is freed
without cancelling the work.

Also, cancel_work_sync() is only really needed when running the work
on a global or shared workqueue. If it's a private one, then destroy_workqueue()
is good enough to cancel the work.

Sounds like more of a job for static code analysis? Coccinelle?

  reply	other threads:[~2019-02-05 19:12 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-04 22:09 [RFC v1 0/3] Address potential user-after-free on module unload Sven Van Asbroeck
2019-02-04 22:09 ` [RFC v1 1/3] workqueue: Add resource-managed version of INIT_[DELAYED_]WORK() Sven Van Asbroeck
2019-02-08 17:06   ` Tejun Heo
2019-02-08 18:15     ` Sven Van Asbroeck
2019-02-04 22:09 ` [RFC v1 2/3] max17042_battery: fix potential user-after-free on module unload Sven Van Asbroeck
2019-02-05  8:27   ` Dmitry Torokhov
2019-02-05 14:27     ` Sven Van Asbroeck
2019-02-05 17:21       ` Sebastian Reichel
2019-02-04 22:09 ` [RFC v1 3/3] cap11xx: " Sven Van Asbroeck
2019-02-05  8:18   ` Dmitry Torokhov
2019-02-05  8:34     ` Dmitry Torokhov
2019-02-05 21:24     ` Jacek Anaszewski
2019-02-05 21:43       ` Dmitry Torokhov
2019-02-05 22:03         ` Sven Van Asbroeck
2019-02-05 14:57 ` [RFC v1 0/3] Address " Kees Cook
2019-02-05 15:22   ` Sven Van Asbroeck
2019-02-05 18:43     ` Greg KH
2019-02-05 19:12       ` Sven Van Asbroeck [this message]
2019-02-06 16:46         ` Greg KH
2019-02-06 17:30           ` Dmitry Torokhov
2019-02-06 17:49             ` Sven Van Asbroeck
2019-02-08  6:51             ` Greg KH
2019-02-05 18:42   ` Greg KH
2019-02-07 21:49   ` Sven Van Asbroeck
2019-02-07 22:20     ` Dmitry Torokhov
2019-02-07 22:27       ` Sven Van Asbroeck
2019-02-07 22:32       ` Sven Van Asbroeck
2019-02-07 22:48         ` Dmitry Torokhov
2019-02-08  4:30         ` Miguel Ojeda
2019-02-10 18:05           ` Sven Van Asbroeck
2019-02-14  1:11             ` Miguel Ojeda
2019-02-14 15:23               ` Sven Van Asbroeck
     [not found]     ` <CAGngYiXcogd69n-MvBD1n5ZJpBzqCau8UOfLMgXEXLnAev=srw@mail.gmail.com>
     [not found]       ` <alpine.DEB.2.21.1902080745480.4201@hadrien>
2019-02-14 17:52         ` Fwd: " Sven Van Asbroeck

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