[issue871] gtk2 related: X mouse pointer jumps and sticks to top left corner

Rumko rumcic at gmail.com
Tue Dec 11 10:57:32 PST 2007

I tested this patch (I'm also another one, who got his mouse stuck in X) and I
get _many_ messages from firefox "kernel: pid 1158 (firefox-bin) signal return
from user: illegal FP MXCSR ffff0010" (the message repeats and does not
change) and the firefox process itself seems to be stuck, eating up as much
CPU as it can, but doesn't do anything.

Matthew Dillon wrote:

>     Ok, it looks like firefox is messing up the signal stack and this
>     caused a GP fault in the kernel due to reserved bits in the MXCSR
>     field in the floating point saved state being set by userland.
>     I have added code to report and clear the bits.  I do not know why
>     firefox is blowing up the state, though.
>     I also fixed a bug in krateprintf() in kern/subr_prf.c (not included)...
>     I committed that fix directly.
>     PATCH #2 enclosed.
> -Matt
> Matthew Dillon
> <dillon at backplane.com>
> Index: platform/pc32/i386/machdep.c
> ===================================================================
> RCS file: /cvs/src/sys/platform/pc32/i386/machdep.c,v
. ..
>  /*
>   * Thread priorities.  Typically only one thread from any given

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