From 9d7cc536e261a7d207476115dac6058c38f469bd Mon Sep 17 00:00:00 2001
From: Mark Johnston <markj@FreeBSD.org>
Date: Thu, 23 Feb 2023 21:56:36 -0500
Subject: [PATCH] buf: Make bufspace_daemon_shutdown() a no-op after a panic

This function doesn't need to do anything in that context, and calling
wakeup() can lead to recursive panics.

Discussed with:	mhorne
MFC after:	1 week
---
 sys/kern/vfs_bio.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index abc3eea9be4e..b40ee382c42a 100644
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -766,6 +766,9 @@ bufspace_daemon_shutdown(void *arg, int howto __unused)
 	struct bufdomain *bd = arg;
 	int error;
 
+	if (KERNEL_PANICKED())
+		return;
+
 	BD_RUN_LOCK(bd);
 	bd->bd_shutdown = true;
 	wakeup(&bd->bd_running);