Does anybody know which kind of protection is encoded in ptrace.c:69:
/* This is a hack for non-kernel-mapped video buffers and similar */
if (MAP_NR(page) >= MAP_NR(high_memory))
By this reason gdb shows all user-mapped io as zeros.
Same time, put_long enable to write to such memory !
So when You enter something like 'set *p = 0xff' gdb'ing program
which has p->video_memory, You will see appearing pixels, but 'p *p'
prints only zeros.
Elimination of this check does not destroy something: gdb shows right
It looks clean that above problem is not very important, but just
programmer debugging some application for Linux used to control some
on MIPS embedded computer, which mmap'ed to device registers and don't
why they are all clean :-)