linux-kernel - Re: [3.4-rc3] Thread overran stack, or stack corrupted

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]

Date:	Tue, 17 Apr 2012 13:20:51 -0700
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	Dave Jones <davej@...hat.com>,
	Linux Kernel <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [3.4-rc3] Thread overran stack, or stack corrupted

On Tue, Apr 17, 2012 at 10:21 AM, Dave Jones <davej@...hat.com> wrote:
> My syscall fuzzer started showing up some cases where it we seem to be
> overrunning the stack.  I added a WARN_ON when the stack is really low,
> to see if there's a deep call trace, but it's not really telling me much ..

You seem to have added the WARN_ON() to check_stack_usage() itself.

That's not very useful, because it uses the *current* stack pointer.
Instead, how about just calling "show_trace()" with the actual lowest
stack pointer at that point? That should show you the stack as it was
when it was at its lowest, and that could actually be useful.

IOW, just something like

    show_trace(NULL, NULL, (void *)end_of_stack(p) + lowest_to_date, NULL);

Or something kind of like that. Yes?

                           Linus
--
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/