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From: Al Viro <viro@ZenIV.linux.org.uk>
To: Julia Lawall <julia.lawall@lip6.fr>
Cc: Joe Perches <joe@perches.com>, Kees Cook <keescook@chromium.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Jamal Hadi Salim <jhs@mojatatu.com>,
	Cong Wang <xiyou.wangcong@gmail.com>,
	Jiri Pirko <jiri@resnulli.us>,
	"David S. Miller" <davem@davemloft.net>,
	Network Development <netdev@vger.kernel.org>
Subject: Re: [PATCH] net: sched: Fix memory exposure from short TCA_U32_SEL
Date: Mon, 27 Aug 2018 03:35:26 +0100	[thread overview]
Message-ID: <20180827023526.GA6515@ZenIV.linux.org.uk> (raw)
In-Reply-To: <alpine.DEB.2.21.1808262159430.2528@hadrien>

On Sun, Aug 26, 2018 at 10:00:46PM -0400, Julia Lawall wrote:
> 
> 
> On Sun, 26 Aug 2018, Al Viro wrote:
> 
> > On Sun, Aug 26, 2018 at 03:26:54PM -0700, Joe Perches wrote:
> > > On Sun, 2018-08-26 at 22:24 +0100, Al Viro wrote:
> > > > On Sun, Aug 26, 2018 at 11:57:57AM -0700, Joe Perches wrote:
> > > >
> > > > > > That, BTW, is why I hate the use of sizeof(*p) in kmalloc, etc.
> > > > > > arguments.  typeof is even worse in that respect.
> > > > >
> > > > > True.  Semantic searches via tools like coccinelle could help here
> > > > > but those searches are quite a bit slower than straightforward greps.
> > > >
> > > > Those searches are .config-sensitive as well, which can be much more
> > > > unpleasant than being slow...
> > >
> > > Are they?  Julia?
> >
> > They work pretty much on preprocessor output level; if something it ifdef'ed
> > out on given config, it won't be seen...
> 
> Coccinelle doesn't care what is ifdef'd out.  It only misses the things it
> can't parse.  Very strange ifdefs could indeed cause that, but it should
> be a minor problem.

OK, but... what does it do when it sees two definitions of a structure
in different branches of #if/#else/#endif?  I think I'm confused about
what it can and cannot do; to restate the original problem:
	* we need to find all places where instances of given type
are created.  Assume it never is a member of struct/union/array and
no static or auto duration instances exist - everything is dynamically
allocated somewhere.

Can coccinelle do that and if it can, what are the limitations?

  reply	other threads:[~2018-08-27  2:35 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-26  5:58 [PATCH] net: sched: Fix memory exposure from short TCA_U32_SEL Kees Cook
2018-08-26  6:15 ` Al Viro
2018-08-26  6:19   ` Kees Cook
2018-08-26 17:30     ` Jamal Hadi Salim
2018-08-26 21:56       ` Kees Cook
2018-08-27 11:46         ` Jamal Hadi Salim
2018-08-27 14:08           ` Kees Cook
2018-08-27 14:26             ` Roman Mashak
2018-08-26 17:32     ` Al Viro
2018-08-26 18:57       ` Joe Perches
2018-08-26 21:24         ` Al Viro
2018-08-26 22:26           ` Joe Perches
2018-08-26 22:43             ` Al Viro
2018-08-27  2:00               ` Julia Lawall
2018-08-27  2:35                 ` Al Viro [this message]
2018-08-27  3:35                   ` Julia Lawall
2018-08-27  4:04                     ` Al Viro
2018-08-27  4:41                       ` Julia Lawall
2018-08-27  1:59             ` Julia Lawall
2018-08-26 22:57       ` Al Viro
2018-08-27 11:57         ` Jamal Hadi Salim
2018-08-27 21:31           ` Cong Wang
2018-08-28  0:03             ` Al Viro
2018-08-28 15:59               ` Al Viro
2018-08-31  4:03                 ` Al Viro
2018-08-29 19:07               ` Cong Wang
2018-08-29 21:33                 ` Al Viro
2018-08-26 21:22 ` David Miller

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