Date: Wed, 10 Sep 1997 13:21:30 +1000 From: Bruce Evans <bde@zeta.org.au> To: hfwirth@ping.at, jlemon@americantv.com Cc: bde@zeta.org.au, emulation@FreeBSD.ORG Subject: Re: Doscmd, debugging with gdb Message-ID: <199709100321.NAA07491@godzilla.zeta.org.au>
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>The problem appears to be that gdb is unable to write to any
>region that is of type OBJT_DEFAULT (default) in the above
>map, even though it is marked writable. gdb doesn't have any
>problems reading from the address, though.
>
>A simple test case:
>
> > echo 'main() {}' > test.c
> > cc -g test.c
> > gdb a.out
> (gdb) b main
> (gdb) r
> > cat /proc/<pid>/map
> [.. snip ..]
> 0x8012000 0x8014000 0 2 rwx COW vnode
> 0x8014000 0x801c000 0 8 rwx default
> [.. snip ..]
> (gdb) set *0x8012000 = 0
> (gdb) set *0x8014000 = 0
> Error accessing memory address 0x8014000: Bad address.
`w' apparently means write-protected here :-). All the r-x COW vnodes
are writable and all the rwx COW vnodes are non-writable.
Bruce
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