cvs commit: src/sys/amd64/amd64 machdep.c src/sys/i386/i386 machdep.c src/sys/pc98/pc98 machdep.c

John Baldwin jhb at
Tue Mar 14 16:13:56 UTC 2006

jhb         2006-03-14 16:13:55 UTC

  FreeBSD src repository

  Modified files:
    sys/amd64/amd64      machdep.c 
    sys/i386/i386        machdep.c 
    sys/pc98/pc98        machdep.c 
  Don't allow userland to set hardware watch points on kernel memory at all.
  Previously, we tried to allow this only for root.  However, we were calling
  suser() on the *target* process rather than the current process.  This
  means that if you can ptrace() a process running as root you can set a
  hardware watch point in the kernel.  In practice I think you probably have
  to be root in order to pass the p_candebug() checks in ptrace() to attach
  to a process running as root anyway.  Rather than fix the suser(), I just
  axed the entire idea, as I can't think of any good reason _at all_ for
  userland to set hardware watch points for KVM.
  MFC after:      3 days
  Also thinks hardware watch points on KVM from userland are bad: bde, rwatson
  Revision  Changes    Path
  1.648     +20 -23    src/sys/amd64/amd64/machdep.c
  1.624     +20 -23    src/sys/i386/i386/machdep.c
  1.372     +20 -23    src/sys/pc98/pc98/machdep.c

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