Re: [PATCH] x86 page fault handler not interrupt safe

[Jesper Juhl <juhl@eisenstein.dk>]

Linus Torvalds wrote:

> 
> In particular, does anybody have a buggy Pentium to test with the F0 0F
> lock-up bug? It _should_ be caught with the error-code test (it's a
> protection fault, not a non-present fault and thus the F0 0F case never
> enters the vmalloc path), but it's been several years since the thing..
> 
> If anybody has such a beast, please try this kernel patch _and_ running
> the F0 0F bug-producing program (search for it on the 'net - it must be
> out there somewhere) to verify that the code still correctly handles that
> case.
> 

I have a Thinkpad with a buggy pentium (see cat /proc/cpuinfo below) and 
I tried running the F00F test program available from 
http://lwn.net/2001/0329/a/ltp-f00f.php3 first on a 2.2.17 kernel that 
I've been running for ages without problems I got this output:

Testing for proper f00f instruction handling.
SIGILL received from f00f instruction.  Good.

Then I tried 2.4.4 with your patch applied and got the same output (and 
no lockup), so according to that test program your patch does not break 
the F00F handling code. :-)

If you want me to test other patches, just let me know and I'll be happy 
to do so!

$ cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 5
model           : 8
model name      : Mobile Pentium MMX
stepping        : 1
cpu MHz         : 232.111
fdiv_bug        : no
hlt_bug         : no
sep_bug         : no
f00f_bug        : yes
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 1
wp              : yes
flags           : fpu vme de pse tsc msr mce cx8 mmx
bogomips        : 463.67


Best regards,
Jesper Juhl - juhl@eisenstein.dk