From: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
To: "Aurélien Aptel" <aaptel@suse.com>
Cc: linux-sparse@vger.kernel.org
Subject: Re: using sparse to catch refcount leaks
Date: Thu, 9 Jul 2020 20:48:13 +0200 [thread overview]
Message-ID: <20200709184813.765ebmlta7mojqad@ltop.local> (raw)
In-Reply-To: <871rlk6630.fsf@suse.com>
On Thu, Jul 09, 2020 at 05:50:11PM +0200, Aurélien Aptel wrote:
> Hi,
>
> I was thinking the same mechanism for lock checks (lock() has matching
> unlock()) could be used for detecting refcount leaks (get() has matching
> put()).
>
> This could be used to catch bugs like that:
>
> https://lore.kernel.org/linux-cifs/CAH2r5mtJg0OONLuAYmcggj=M3euDDxRa3Y5-_W1=qxwbeZypqA@mail.gmail.com/T/#mf0e0397aa0b63043d7b3bb0981f0b7323713bfdc
Absolutely.
Sparse's 'context' can be reused for refcounting (conceptually,
it's quite similar to locking). You can even simply reuse the
existing macros __acquires(), ...
That's said, I suppose that in the present case the 'get' is done
by cifs_sb_tlink(). This corresponds to a 'conditional context'
(see __cond_lock()) which somehow annoying to use. I've some
patches improving things here but they need some more work.
Cheers,
-- Luc
next prev parent reply other threads:[~2020-07-09 18:48 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-09 15:50 using sparse to catch refcount leaks Aurélien Aptel
2020-07-09 18:48 ` Luc Van Oostenryck [this message]
2020-07-10 8:59 ` Dan Carpenter
2020-07-13 10:50 ` Aurélien Aptel
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