Re: Strange MXCSR messages?

[Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxx>]

:Joerg Anslik wrote:
:> I enabled "nata" support on one of my boxes lately, and now my
:> /var/log/messages gets flooded with entries like this:
:
:Is the problem not encountered if you recompile from the exact same 
:sources, but with old ATA instead of NATA?
:
:> [...]
:> kernel: pid 54403 (icecast) signal return from user: illegal FP MXCSR
:> ffff0010
:> last message repeated 24 times
:> kernel: pid 9033 (mysqld) signal return from user: illegal FP MXCSR
:> ffff0010
:> last message repeated 7 times
:> [...]
:> I also found it's pretty hard to get information about this "MXCSR"
:> stuff, so if someone could give me a short explanation...? As far as I
:> can tell, it's some kind of register stuff.
:
:MXCSR is the SSE control/status register, and that value means the 
:Underflow Flag bit is set. The other 1 bits are reserved ones, which 
:should *NOT* be set to 1. Attempting to set them to 1 will result in a 
:general protection exception, which is probably what you're seeing here. 
:My guess is, the recent changes to how the signal code in the kernel 
:saves and restores the MXCSR register, introduced this bug, and not 
:NATA. I'll have a look later at the code in question.
:
:Cheers,
:-- 
:         Thomas E. Spanjaard
:         tgen@netphreax.net

    Yah, its unrelated to nata.  I'll get mysqld built up and try to
    figure out what is messing up the signal stack.  firefox and gtk
    have the same problem.

						-Matt