linux-kernel - Re: [patch] NULL pointer check for vma->vm

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: <20080201021917.5db3448d.akpm@linux-foundation.org>
Date:	Fri, 1 Feb 2008 02:19:17 -0800
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	"Kenichi Okuyama" <kenichi.okuyama@...il.com>
Cc:	linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [patch] NULL pointer check for vma->vm_mm

On Fri, 1 Feb 2008 17:24:17 +0900 "Kenichi Okuyama" <kenichi.okuyama@...il.com> wrote:

> First of all, thank you for looking at the patch.
> 
> I do agree that if mm is NULL, system will call Oops anyway.
> However, since it's oops, it does not stop the system, nor call kdump.

That would be a huge bug in kdump?  Surely it dumps when the kernel oopses?

> By calling BUG_ON(), it'll gives us chance of calling kdump at the first chance.
> 
> Since this is very rare to happen, I thought we should capture the incident
> whenever possible. On other hand, because BUG_ON macro is very light,
> I thought this will not harm any performance...
> 
> Forgive me in advance if I was wrong.
> I still think checking mm with BUG_ON here is better than counting on Oops.

But there are probably a million potential NULL-pointer dereferences in the 
kernel.  Why single out this one?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/