- Always call faultin() in _PHOLD() if PS_INMEM is clear. This closes a

  race where a thread could assume that a process was swapped in by
  PHOLD() when it actually wasn't fully swapped in yet.
- In faultin(), always msleep() if PS_SWAPPINGIN is set instead of doing
  this check after bumping p_lock in the PS_INMEM == 0 case.  Also,
  sched_lock is only needed for setting and clearning swapping PS_*
  flags and the swap thread inhibitor.
- Don't set and clear the thread swap inhibitor in the same loops as the
  pmap_swapin/out_thread() since we have to do it under sched_lock.
  Instead, mimic the treatment of the PS_INMEM flag and use separate loops
  to set the inhibitors when clearing PS_INMEM and clear the inhibitors
  when setting PS_INMEM.
- swapout() now returns with the proc lock held as it holds the lock
  while adjusting the swapping-related PS_* flags so that the proc lock
  can be used to test those flags.
- Only use the proc lock to check the swapping-related PS_* flags in
  several places.
- faultin() no longer requires sched_lock to be held by callers.
- Rename PS_SWAPPING to PS_SWAPPINGOUT to be less ambiguous now that we
  have PS_SWAPPINGIN.

1 files changed, 0 insertions, 2 deletions

diff --git a/sys/fs/procfs/procfs_ctl.c b/sys/fs/procfs/procfs_ctl.c
index ff4fb0a..ecc8321 100644
--- a/sys/fs/procfs/procfs_ctl.c
+++ b/sys/fs/procfs/procfs_ctl.c
@@ -144,9 +144,7 @@ procfs_control(struct thread *td, struct proc *p, int op)
 		 * Stop the target.
 		 */
 		p->p_flag |= P_TRACED;
-		mtx_lock_spin(&sched_lock);
 		faultin(p);
-		mtx_unlock_spin(&sched_lock);
 		p->p_xstat = 0;		/* XXX ? */
 		if (p->p_pptr != td->td_proc) {
 			p->p_oppid = p->p_pptr->p_pid;