Re: timer + fpu stuff locks my console race

[Matt Mackall <mpm@selenic.com>]

On Fri, Jun 11, 2004 at 10:53:48PM -0400, Rik van Riel wrote:
> On Wed, 9 Jun 2004 stian@nixia.no wrote:
> 
> > I'm doing some code tests when I came across problems with my program
> > locking my console (even X if I'm using a xterm).
> 
> Reproduced here, on my test system running a 2.6 kernel.
> I did get a kernel backtrace over serial console, though ;)

I stuck some strategic printks in the kernel. The example code's bogus
asm is generating an FPU fault in frstor in its signal handler, that's
bumping us into math_error -> force_sig_info ->
specific_send_sig_info. Then we hit:

        if (LEGACY_QUEUE(&t->pending, sig))

which decides we don't need to send the signal after all and we bail
all the way back out and recurse.

-- 
Mathematics is the supreme nostalgia of our time.