#12 Stack trace showing unknown frames

[Christoph Schwarz]

Frames that can not be matched to any loaded module appear in stack traces.

To reproduce:

coregrind\valgrind.exe -d memcheck\tests\windows\memcheck-x86-windows.exe

Output:

....
--7408:1:aspacem   51: anon 0004000000-00041fffff 2097152 rwx--
....
==7408== Invalid read of size 1
==7408==    at 0x70301CD8: strlen (mc_replace_strmem.c:482)
==7408==    by 0x41FFE98: ???
==7408==    by 0x402830: ??? (memcheck.c:23)
==7408==    by 0x4013EA: __tmainCRTStartup (crtexe.c:309)
==7408==    by 0x41FFFCC: ???
==7408==  Address 0x4201240 is 0 bytes inside a block of size 32 free'd
==7408==    at 0x703012B8: free (vg_replace_malloc.c:456)
...
--7408:1:aspacem   51: anon 0004000000-00045fffff 6291456 rwx-H
...

The frames 0x41FFE98 and 0x41FFFCC appear to originate from memory block 4000000-00045fffff, which doesn't have a module associated with it.

Find out what is the reason for this. See also [#2].