Make funsetown() take a 'struct sigio **' so that the locking can

be done internally.

Ensure that no one can fsetown() to a dying process/pgrp.  We need
to check the process for P_WEXIT to see if it's exiting.  Process
groups are already safe because there is no such thing as a pgrp
zombie, therefore the proctree lock completely protects the pgrp
from having sigio structures associated with it after it runs
funsetownlst.

Add sigio lock to witness list under proctree and allproc, but over
proc and pgrp.

Seigo Tanimura helped with this.

1 files changed, 1 insertions, 4 deletions

diff --git a/sys/kern/kern_proc.c b/sys/kern/kern_proc.c
index 2dde108..8f92331 100644
--- a/sys/kern/kern_proc.c
+++ b/sys/kern/kern_proc.c
@@ -474,16 +474,13 @@ pgdelete(pgrp)
 	PGRP_LOCK_ASSERT(pgrp, MA_NOTOWNED);
 	SESS_LOCK_ASSERT(pgrp->pg_session, MA_NOTOWNED);
 
-	SIGIO_LOCK();
-	PGRP_LOCK(pgrp);
-
 	/*
 	 * Reset any sigio structures pointing to us as a result of
 	 * F_SETOWN with our pgid.
 	 */
 	funsetownlst(&pgrp->pg_sigiolst);
-	SIGIO_UNLOCK();
 
+	PGRP_LOCK(pgrp);
 	if (pgrp->pg_session->s_ttyp != NULL &&
 	    pgrp->pg_session->s_ttyp->t_pgrp == pgrp)
 		pgrp->pg_session->s_ttyp->t_pgrp = NULL;