[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20160702172441.GA22748@pd.tnic>
Date: Sat, 2 Jul 2016 19:24:41 +0200
From: Borislav Petkov <bp@...en8.de>
To: Andy Lutomirski <luto@...nel.org>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org,
linux-arch@...r.kernel.org, Nadav Amit <nadav.amit@...il.com>,
Kees Cook <keescook@...omium.org>, Brian Gerst <brgerst@...il.com>,
"kernel-hardening@...ts.openwall.com" <kernel-hardening@...ts.openwall.com>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Josh Poimboeuf <jpoimboe@...hat.com>, Jann Horn <jann@...jh.net>,
Heiko Carstens <heiko.carstens@...ibm.com>
Subject: Re: [PATCH v4 10/29] x86/die: Don't try to recover from an OOPS on a
non-default stack
On Sun, Jun 26, 2016 at 02:55:32PM -0700, Andy Lutomirski wrote:
> It's not going to work, because the scheduler will explode if we try
> to schedule when running on an IST stack or similar.
>
> This will matter when we let kernel stack overflows (which are #DF)
> call die().
>
> Signed-off-by: Andy Lutomirski <luto@...nel.org>
> ---
> arch/x86/kernel/dumpstack.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
> index ef8017ca5ba9..352f022cfd5b 100644
> --- a/arch/x86/kernel/dumpstack.c
> +++ b/arch/x86/kernel/dumpstack.c
> @@ -245,6 +245,9 @@ void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
> return;
> if (in_interrupt())
> panic("Fatal exception in interrupt");
> + if (((current_stack_pointer() ^ (current_top_of_stack() - 1))
> + & ~(THREAD_SIZE - 1)) != 0)
Ugh, that's hard to parse. You could remove the "!= 0" at least to
shorten it a bit and have one less braces level.
Or maybe even do something like that to make it a bit more readable:
if ((current_stack_pointer() ^ (current_top_of_stack() - 1))
&
~(THREAD_SIZE - 1))
panic("Fatal exception on non-default stack");
Meh.
> + panic("Fatal exception on special stack");
"Fatal exception on non-default stack"
maybe?
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
