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

Rafael J. Wysocki
2008-03-01T01:20:33Z

On Friday, 29 of February 2008, H. Peter Anvin wrote:
> Klaus S. Madsen wrote:
> > open("/dev/mem", O_RDWR) = 5
> > mmap2(NULL, 1282, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_SHARED|MAP_FIXED, 5, 0) = 0
> > mmap2(0xa0000, 393216, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_FIXED, 5, 0xa0) = 0xa0000
> ^^^^^^^^^^^^^^^^^^^^
> > close(5) = 0
> > ioperm(0, 0x400, 0x1) = 0
> > iopl(0x3) = 0
> > access("/sys/bus/pci", R_OK) = 0
> > write(1, "Calling get_mode\n", 17) = 17
> > vm86(0x1, 0xb7f14ccc, 0xb7f14830, 0xc000, 0x18b6 <unfinished ...>
> > --- SIGSEGV (Segmentation fault) @ 0 (0) ---
> > +++ killed by SIGSEGV (core dumped) +++
>
> This is the VGA BIOS being mapped, it's mapped PROT_READ|PROT_WRITE, but
> no PROT_EXEC; if the kernel is NX-capable it *should* segfault trying
> to execute out of this area, which is exactly what will happen when vm86
> executes INT 10h.
>
> If we can find that mmap() in the s2ram source code and add PROT_EXEC to
> it, it would be interesting.

This is in radeontool.c, line 91, AFAICS.

Thanks,
Rafael