C-g crash

C-g crash

[Richard Stallman]

The backtrace after the crash showed one stack frame
calling __kernel_vsyscall.

Does anyone know what that does?

Re: C-g crash

[Andreas Schwab]

Richard Stallman <rms@gnu.org> writes:

> The backtrace after the crash showed one stack frame
> calling __kernel_vsyscall.
>
> Does anyone know what that does?

It's the syscall trampoline provided by the kernel.

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
PGP key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: C-g crash

[Richard Stallman]

    It's the syscall trampoline provided by the kernel.

Could you explain more precisely?

Until very recently, I never saw Emacs stopped in __kernel_vsyscall.
Is it something fairly new?

Is there a way to determine which system call it is
by looking at some of the registers?

Re: C-g crash

[Andreas Schwab]

Richard Stallman <rms@gnu.org> writes:

>     It's the syscall trampoline provided by the kernel.
>
> Could you explain more precisely?

It's also known as vDSO.  That's pretty much all I know about it.

> Is there a way to determine which system call it is
> by looking at some of the registers?

It also contains the signal trampoline, so you may just be looking at a
signal frame.

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
PGP key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: C-g crash

[Richard Stallman]

    > Is there a way to determine which system call it is
    > by looking at some of the registers?

    It also contains the signal trampoline, so you may just be looking at a
    signal frame.

If someone can tell me how to diagnose this, I would appreciate it.

I have started editing using the souces as of 2006-07-10.
We will see if it crashes.  I have a suspicion that the sit-for
change is somehow responsible, but that is not yet proved.