git: kernel - Fix pmap_remove() issue.

Matthew Dillon dillon at
Thu Aug 23 20:55:40 PDT 2012

commit 554cf9ac8ff4af8eedd0f5896dfa5d2e5f61038d
Author: Matthew Dillon <dillon at>
Date:   Thu Aug 23 20:44:53 2012 -0700

    kernel - Fix pmap_remove() issue.
    * When the inner loop of pmap_remove() broke out due to pmap_remove_pte()
      blocking it 'jumped' the sindex to pdnxt, thus any remaining pages in
      that page table page would get skipped.
    * pmap_remove_pte() and friends used to return non-zero if they 'blocked'.
      Unfortunately they could actually block whether they returned 0 or non-zero,
      causing the problem.  Remove the check entirely.
    * Adjust misc functions which we no longer need the return value for.
    * I don't know if this had anything to do with the wire_count panic.
      The failure mode should have been caught by numerous other assertions
      in the code but wasn't.  get_ptbase() relies on a test of pmap->pm_cached
      to determine if a page directory page mapping changes so it should not
      have been possible for it to continue the loop and access a stale ptep.
      If it were possible it might account for a wire_count panic later on but
      it doesn't seem like it should be possible.

Summary of changes:
 sys/platform/pc32/i386/pmap.c |   94 +++++++++++++++++++---------------------
 1 files changed, 45 insertions(+), 49 deletions(-)

DragonFly BSD source repository

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