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.

3 files changed, 3 insertions, 3 deletions

diff --git a/sys/net/bpf.c b/sys/net/bpf.c
index 325af54..1476498 100644
--- a/sys/net/bpf.c
+++ b/sys/net/bpf.c
@@ -368,7 +368,7 @@ bpfclose(dev, flags, fmt, td)
 		callout_stop(&d->bd_callout);
 	d->bd_state = BPF_IDLE;
 	BPFD_UNLOCK(d);
-	funsetown(d->bd_sigio);
+	funsetown(&d->bd_sigio);
 	mtx_lock(&bpf_mtx);
 	if (d->bd_bif)
 		bpf_detachd(d);
diff --git a/sys/net/if_tap.c b/sys/net/if_tap.c
index 45ce21f..ef0a36d 100644
--- a/sys/net/if_tap.c
+++ b/sys/net/if_tap.c
@@ -491,7 +491,7 @@ tapclose(dev, foo, bar, td)
 		splx(s);
 	}
 
-	funsetown(tp->tap_sigio);
+	funsetown(&tp->tap_sigio);
 	selwakeup(&tp->tap_rsel);
 
 	tp->tap_flags &= ~TAP_OPEN;
diff --git a/sys/net/if_tun.c b/sys/net/if_tun.c
index a6c89fb..18435fd 100644
--- a/sys/net/if_tun.c
+++ b/sys/net/if_tun.c
@@ -335,7 +335,7 @@ tunclose(dev_t dev, int foo, int bar, struct thread *td)
 		splx(s);
 	}
 
-	funsetown(tp->tun_sigio);
+	funsetown(&tp->tun_sigio);
 	selwakeup(&tp->tun_rsel);
 
 	TUNDEBUG ("%s%d: closed\n", ifp->if_name, ifp->if_unit);