alq, siftr: add panic/debugger checks to shutdown hooks

Don't try to gracefully terminate the pkt_manager thread if the
scheduler is not running.

We should not attempt to shutdown ald if RB_NOSYNC is set, and must not
if the scheduler is stopped (the function calls wakeup()).

Reviewed by:	markj
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D42340

2 files changed, 14 insertions, 6 deletions

diff --git a/sys/kern/kern_alq.c b/sys/kern/kern_alq.c
index 51fd66f2fe9f..1bcce92509c5 100644
--- a/sys/kern/kern_alq.c
+++ b/sys/kern/kern_alq.c
@@ -37,19 +37,20 @@
 
 #include <sys/param.h>
 #include <sys/systm.h>
+#include <sys/alq.h>
+#include <sys/eventhandler.h>
+#include <sys/fcntl.h>
 #include <sys/kernel.h>
 #include <sys/kthread.h>
 #include <sys/lock.h>
+#include <sys/malloc.h>
 #include <sys/mount.h>
 #include <sys/mutex.h>
 #include <sys/namei.h>
 #include <sys/proc.h>
-#include <sys/vnode.h>
-#include <sys/alq.h>
-#include <sys/malloc.h>
+#include <sys/reboot.h>
 #include <sys/unistd.h>
-#include <sys/fcntl.h>
-#include <sys/eventhandler.h>
+#include <sys/vnode.h>
 
 #include <security/mac/mac_framework.h>
 
@@ -228,6 +229,9 @@ ald_shutdown(void *arg, int howto)
 {
 	struct alq *alq;
 
+	if ((howto & RB_NOSYNC) != 0 || SCHEDULER_STOPPED())
+		return;
+
 	ALD_LOCK();
 
 	/* Ensure no new queues can be created. */
diff --git a/sys/netinet/siftr.c b/sys/netinet/siftr.c
index fbb47fc4a521..13b26e61b5d4 100644
--- a/sys/netinet/siftr.c
+++ b/sys/netinet/siftr.c
@@ -74,6 +74,7 @@
 #include <sys/mutex.h>
 #include <sys/pcpu.h>
 #include <sys/proc.h>
+#include <sys/reboot.h>
 #include <sys/sbuf.h>
 #include <sys/sdt.h>
 #include <sys/smp.h>
@@ -1300,8 +1301,11 @@ siftr_sysctl_enabled_handler(SYSCTL_HANDLER_ARGS)
 }
 
 static void
-siftr_shutdown_handler(void *arg)
+siftr_shutdown_handler(void *arg, int howto)
 {
+	if ((howto & RB_NOSYNC) != 0 || SCHEDULER_STOPPED())
+		return;
+
 	if (siftr_enabled == 1) {
 		siftr_manage_ops(SIFTR_DISABLE);
 	}