Re: __stack_start for ColdFire uClinux

Geert Uytterhoeven <[email protected]>
Newsgroups gmane.linux.uclinux.devel
Message-ID <CAMuHMdW5vX1T6kEsqfQVMsFSp6r_KpG3hsQxrCTksV0b5Wu=qw@mail.gmail.com>
Hi Larry,

On Thu, Oct 4, 2012 at 7:15 AM, Larry Baker <[email protected]> wrote:
> On Oct 3, 2012, at 10:00 PM, Geert Uytterhoeven wrote:
>
>>> I'm still looking for the conditions it takes to have something like
>>> show_registers() in arch/m68k/kernel/traps.c called when the trap occurs.
>>
>> The registers are only printed for exceptions caused in kernel mode.
>
> Is this a difference between uClinux and Linux?
>
> I have worked on bugs in IBM's J9 JVM on ARM Linux (MontaVista 2.4 kernel) which resulted in register and stack dumps of user code (the JVM) to the console and /var/log/messages for access violations (illegal instruction fetch).  Like you say, I originally thought those must have been kernel traps.  But, they were not followed by an Oops.  I tracked down the kernel code that was printing the messages and convinced myself that the fault was actually occurring in user mode, not kernel mode -- which made much more sense for a JVM.

Typically, you do not want to spam the kernel log for exceptions in user mode,
as this may allow a DoS attack.

It may be useful for debugging, though.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
_______________________________________________
uClinux-dev mailing list
[email protected]
http://mailman.uclinux.org/mailman/listinfo/uclinux-dev
This message was resent by [email protected]
To unsubscribe see:
http://mailman.uclinux.org/mailman/options/uclinux-dev
lmpx.com only provides a reader for public news (NNTP) servers. It is not affiliated with the servers or forums shown here and is not responsible for the content of articles, which is written by their respective authors.