From: Dan Carpenter <dan.carpenter@oracle.com>
To: "Aurélien Aptel" <aaptel@suse.com>
Cc: linux-sparse@vger.kernel.org
Subject: Re: using sparse to catch refcount leaks
Date: Fri, 10 Jul 2020 11:59:27 +0300 [thread overview]
Message-ID: <20200710085927.GN2549@kadam> (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
You might be better off copying the Smatch's locking test instead of
Sparse's. Smatch does cross function flow analysis which can help.
In this CIFS case, the leak is on the success path (as well as the
failure path) so my theory would be that it would be caught in testing
and will only cause false positives for static analysis. I can't see
any automated way to know which success paths should take a reference
and which should not.
regards,
dan carpenter
next prev parent reply other threads:[~2020-07-10 9:01 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
2020-07-10 8:59 ` Dan Carpenter [this message]
2020-07-13 10:50 ` Aurélien Aptel
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