From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kees Cook <keescook@chromium.org>, Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Hellstrom <thellstrom@vmware.com>,
Andi Kleen <ak@linux.intel.com>,
Daniel Micay <danielmicay@gmail.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] kref: Avoid null pointer dereference after WARN
Date: Tue, 27 Jun 2017 13:00:16 +0200 [thread overview]
Message-ID: <20170627110013.GA3026@zx2c4.com> (raw)
In-Reply-To: <20170627070626.GH29909@kroah.com>
On Tue, Jun 27, 2017 at 09:06:26AM +0200, Greg Kroah-Hartman wrote:
> I remember one complaint was that WARN_ON was "huge" and this bloated
> the kernel code a lot. But then that got fixed up. Is BUG_ON going to
> cause the same complaint again?
Complaint or not, I'm pretty sure using BUG_ON here is the right
behavior. If removing it will result in a null pointer dereference (and
subsequent function call), that's bad news bears, especially on systems
with a zero mmap_min_addr or combined with other bugs.
If somehow a driver manages to pass a NULL as the release function,
something is really messed up and the kernel should "safely" panic
instead.
>
> thanks,
>
> greg k-h
--
Jason A. Donenfeld
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next prev parent reply other threads:[~2017-06-27 11:00 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-27 3:52 [PATCH] kref: Avoid null pointer dereference after WARN Kees Cook
2017-06-27 7:06 ` Greg Kroah-Hartman
2017-06-27 11:00 ` Jason A. Donenfeld [this message]
2017-06-27 14:49 ` Andi Kleen
2017-06-27 19:11 ` Jason A. Donenfeld
2017-06-27 19:29 ` Andi Kleen
2017-06-28 11:26 ` Michal Hocko
2017-06-27 18:34 ` Kees Cook
2017-07-05 15:37 ` Peter Zijlstra
2017-06-28 11:57 ` Greg Kroah-Hartman
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