From mboxrd@z Thu Jan 1 00:00:00 1970 From: To: Subject: More mmap/Linux questions Date: Thu, 31 Aug 2000 09:52:00 -0000 Message-id: <0008319677.AA967740722@mailserver.aerosimulation.com> X-SW-Source: 2000-08/msg00167.html A previous thread on mmap stated that the problem is in Linux. I have a cluster of Linux boxes connected via PCI reflective memory. They are programmed in ADA and have 85 data structures mmaped into the reflective memory. If I print or x any any structure which has been mmapped all I get are zeros. My understanding is this is because of ptrace in the linux kernel. The previous thread indicated this restriction was because some hardware devices don't like arbitrary accesses. This restriction seems like swatting flies with a sledgehammer. Can't MTTR or something be used to protect touchy hardware rather than prohibiting all access to addresses above CPU memory? Can someone familiar with the Linux Kernel (2.2 or higher) explain this in more detail. Can I patch the kernel to get rid of this behaviour?