Subject: Re: [PATCH] uvm_map.c
To: J. Scott Kasten <>
From: Jason Thorpe <>
List: port-m68k
Date: 02/29/2000 16:37:23
On Tue, 29 Feb 2000 18:42:37 -0500 
 "J. Scott Kasten" <> wrote:

 > I researched the archives, and the port-m68k list in May of 1999 had discussion
 > about exactly this type of issue from Chuck Cranor and Ken Nakata.  Chuck
 > found an issue with pointer wrap around in uvm_amap.c.  His patch was applied
 > back at release 1.9 of the file.  I verified that his patch was still in the
 > current release, however, I was still having the problem.  This indicated to
 > me that there must be other places where this can happen.
 > I beleive that I found one such place in uvm_map.c release  After
 > inserting a one line conditional for the wrap problem and recompiling the
 > kernel, I am pleased to say that I have not seen the error in over 4 days
 > now.  I've kept the box compiling c++ code or otherwise abusing it for
 > the entire 4 days, 24 hours a day.  I was getting the problem every 4 to
 > 8 hours before.  Therefore, I beleive the problem is fixed and offer the
 > enclosed diff to the port maintainers for consideration.

It appears that this code block is in the function uvm_map_submap().  This
function is used to create submaps of the kernel_map.  I.e. the function
is called only during bootstrap, and the VA range is already checked.

I don't think this is the reason your system is losing the way it is.

        -- Jason R. Thorpe <>