linux-kernel - Re: [PATCH v2 03/14] notifiers: Assert that RCU is watching in notify

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CALCETrUDeKq1HKpDrbzDExb2sk7hXSe0E0yQ7eZdhfHH4e1baA@mail.gmail.com>
Date:	Mon, 22 Jun 2015 10:03:30 -0700
From:	Andy Lutomirski <luto@...capital.net>
To:	Borislav Petkov <bp@...en8.de>
Cc:	Kees Cook <keescook@...omium.org>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Oleg Nesterov <oleg@...hat.com>,
	Denys Vlasenko <vda.linux@...glemail.com>,
	Brian Gerst <brgerst@...il.com>,
	Frédéric Weisbecker <fweisbec@...il.com>,
	X86 ML <x86@...nel.org>, Rik van Riel <riel@...hat.com>
Subject: Re: [PATCH v2 03/14] notifiers: Assert that RCU is watching in notify_die

On Mon, Jun 22, 2015 at 9:33 AM, Borislav Petkov <bp@...en8.de> wrote:
> On Mon, Jun 22, 2015 at 09:26:13AM -0700, Andy Lutomirski wrote:
>> notify_die is misnamed and has little to do with death. It's really
>> just notifying about an exception, and we might end up oopsing,
>> sending a signal, or neither.
>
> But if we oops and wedge solid afterwards, it might happen that only the
> first splat comes out on the console, no? And that will be the lockdep
> splat which would be useless for debugging the actual problem...
>

The rcu_lockdep_assert should be merely a warning, not a full OOPS.  I
think that, if rcu_lockdep_assert hangs, then we should fix that
rather than avoiding debugging checks.

--Andy
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
Please read the FAQ at  http://www.tux.org/lkml/