Re: Regression in 2.6.25-rc3: s2ram segfaults before suspending

Klaus S. Madsen
2008-02-28T19:54:48Z

On Thu, Feb 28, 2008 at 11:31:13 -0800, H. Peter Anvin wrote:
> Klaus S. Madsen wrote:
> >>
> >>Typically, when the kernel reflects an error in VM86 mode it will update
> >>the structure in memory (in your case, the vm86plus_struct) to reflect
> >>the context. Would it be possible for you to read it out?
> >Hmm. As far as I can tell, its actually using the vm86old system call?
> >That's at least what the comment in libx86 states.
> >
> >However the contents of struct vm86_struct after the segfault is:
> >
> >(gdb) print context.vm
> >$2 = {regs = {ebx = 0, ecx = 0, edx = 0, esi = 0, edi = 0, ebp = 0,
> > eax = 20227, __null_ds = 0, __null_es = 0, __null_fs = -1071579136,
> > __null_gs = 0, orig_eax = -1, eip = 6326, cs = 49152, __csh = 0,
> > eflags = 209410, esp = 4090, ss = 256, __ssh = 0, es = 0, __esh = 0,
> > ds = 64, __dsh = 0, fs = 0, __fsh = 0, gs = 0, __gsh = 0}, flags = 0,
> > screen_bitmap = 0, cpu_type = 0, int_revectored = {__map = {0, 0, 0,0,
> > 0, 0, 0, 2147483648}}, int21_revectored = {__map = {0, 0, 0, 0, 0,
> > 0, 0, 0}}}
> >
> >My version of glibc does not seem to have vm86old declared, so I haven't
> >tried to remove the assembly code.
> >
> >Should I try to change it to use vm86, instead of vm86old?
> >
>
> Yes, that would probably be a good idea. To some degree, I guess it
> really has nothing to do with the more fundamental issue, but it's
> somewhat odd.
Ok. I tried changing the code from the assembly to do:

vm86(VM86_ENTER, vm)

instead. vm the vm86plus_struct structure fill in exactly the same way
as vm86_struct.

The output from GDB after the segfault is exactly the same as
previously, and all the fields in vm86plus_info_struct is zero.

> I'll pick apart the state above looking for fishiness as soon as I get
> back from lunch.
Great, thanks.

--
Kind regards
Klaus S. Madsen