[Crash-utility] is_page_ptr vs. x86_64_kvtop
Hi Dave, et al.,
I have this little problem. I am trying to get a lustre file system
extension working again. It used to work, but does no more.
It first calls is_page_ptr(kvaddr, &kpaddr) to convert a virtual
address into a physical address, and then calls:
readmem(kpaddr, PHYSADDR, buf, used,
"trace page data", RETURN_ON_ERROR)
to fetch the bytes. Updating the release to SLES-11 SP2 causes
this to now fail. In my debugging of crash/gdb, this:
is_page_ptr (addr=18446719884937843744, phys=0x7fffffffd370) at
memory.c:11448
11448 if (IS_SPARSEMEM()) {
(gdb) p/x addr
$8 = 0xffffea001cdad420
is about to fail. However, this:
crash> gdb x/4xg 0xffffea001cdad420
works just fine. I've stepped through x_command until it gets to
x86_64_kvtop() where I'm finding the logic a little twisty.
But it pretty clearly does not rely on section_mem_map_addr() stuff.
So, here's my point: this is confusing. What should I look for
to determine why "is_page_ptr()" is saying 0xffffea001cdad420
is invalid while "x86_64_kvtop()" is saying that it is and its
physical address is 0x87afad420?
878 return(readmem(addr, memtype, buf, len,
(gdb) s
readmem (addr=0xffffea001cdad420, memtype=0x1, buffer=0x5d85d10, size=0x8,
type=0x945f0a "gdb_readmem_callback", error_handle=0x2) at memory.c:1991
0xffffea001cdad420: PML4 DIRECTORY: ffffffff81623000
PAGE DIRECTORY: 87fff7067
PUD: 87fff7000 => 87fff6067
PMD: 87fff6730 => 800000087ae001e3
PAGE: 87ae00000 (2MB)
PTE PHYSICAL FLAGS
800000087ae001e3 87ae00000 (PRESENT|RW|ACCESSED|DIRTY|PSE|GLOBAL|NX)
(gdb) p physpage
$34 = 0x87afad420
0xffffea001cdad420: 0x0200000000000000 0xffffffff00000001
0xffffea001cdad430: 0x0000000000000000 0x0000000000000000
Help, please? Thank you!