[Bug-mit-scheme] [bug #36757] Microcode seg faults under 64-bit NetBSD 5.1.2 (amd64)

[Henry Wu]

URL:
  <http://savannah.gnu.org/bugs/?36757>

                 Summary: Microcode seg faults under 64-bit NetBSD 5.1.2
(amd64)
                 Project: MIT/GNU Scheme
            Submitted by: mhwu
            Submitted on: Sat 30 Jun 2012 03:32:32 PM EDT
                Category: microcode
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect behavior
                  Status: None
                 Privacy: Public
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                Keywords: 

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Details:

The microcode immediately quits upon invocation with a segmentation fault
under the captioned OS.

Upon further investigation, it is system function mmap called with MAP_FIXED
that seg faults.  Calling code is in memmag.c -> ux.c

If I force mmap never to be called with MAP_FIXED (letting the surrounding
code return failure rather than letting it fault), then the runtime tries to
start, but immediately quits within Scheme reporting: "SIGSEGV ... Address not
mapped to object ..." and then end of stream without further chance to
interact.  But the runtime ran enough to print [error] prompts and such.

I don't immediately understand how the current C memory allocation scheme
works to know how to proceed further to debug ... but from a cursory glance,
MAP_FIXED should be allowed to fail like the way I forced it and the system
should still recover.

Henry





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