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

Ingo Molnar
2008-02-29T21:27:22Z

* H. Peter Anvin <hpa@zytor.com> 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.

Klaus, could you send your .config as well? Lets make sure that NX is
even relevant in this context.

Ingo