From 7f03d08c716c6f95ed7988905e0850cbba34c3eb Mon Sep 17 00:00:00 2001
From: Taylor R Campbell <riastradh@NetBSD.org>
Date: Sat, 11 Sep 2021 11:18:42 +0000
Subject: [PATCH] sys: Skip suspendsched on cpu_reboot if we're in ddb.

If we're in ddb, the scheduler and all other CPUs are quiesced
anyway.  But suspendsched will try to take an adaptive lock, which
causes it to crash and re-enter ddb, which isn't very useful for
rebooting.
---
 sys/arch/amd64/amd64/machdep.c     | 11 +++++++++--
 sys/arch/i386/i386/machdep.c       | 11 +++++++++--
 sys/arch/sparc64/sparc64/machdep.c | 11 +++++++++--
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/sys/arch/amd64/amd64/machdep.c b/sys/arch/amd64/amd64/machdep.c
index 86ed809f5b9a..a1ba09316f52 100644
--- a/sys/arch/amd64/amd64/machdep.c
+++ b/sys/arch/amd64/amd64/machdep.c
@@ -700,8 +700,15 @@ cpu_reboot(int howto, char *bootstr)
 		       config_detach_all(boothowto) ||
 		       vfs_unmount_forceone(curlwp))
 			;	/* do nothing */
-	} else
-		suspendsched();
+	} else {
+		int ddb = 0;
+#ifdef DDB
+		extern int db_active; /* XXX */
+		ddb = db_active;
+#endif
+		if (!ddb)
+			suspendsched();
+	}
 
 	pmf_system_shutdown(boothowto);
 
diff --git a/sys/arch/i386/i386/machdep.c b/sys/arch/i386/i386/machdep.c
index 0b9c82ab8573..a4058ee83da5 100644
--- a/sys/arch/i386/i386/machdep.c
+++ b/sys/arch/i386/i386/machdep.c
@@ -766,8 +766,15 @@ cpu_reboot(int howto, char *bootstr)
 		       config_detach_all(boothowto) ||
 		       vfs_unmount_forceone(curlwp))
 			;	/* do nothing */
-	} else
-		suspendsched();
+	} else {
+		int ddb = 0;
+#ifdef DDB
+		extern int db_active; /* XXX */
+		ddb = db_active;
+#endif
+		if (!ddb)
+			suspendsched();
+	}
 
 	pmf_system_shutdown(boothowto);
 
diff --git a/sys/arch/sparc64/sparc64/machdep.c b/sys/arch/sparc64/sparc64/machdep.c
index 8a1e3538bc8f..82fa98807723 100644
--- a/sys/arch/sparc64/sparc64/machdep.c
+++ b/sys/arch/sparc64/sparc64/machdep.c
@@ -573,8 +573,15 @@ cpu_reboot(int howto, char *user_boot_string)
 		       config_detach_all(boothowto) ||
 		       vfs_unmount_forceone(l))
 			;	/* do nothing */
-	} else
-		suspendsched();
+	} else {
+		int ddb = 0;
+#ifdef DDB
+		extern int db_active; /* XXX */
+		ddb = db_active;
+#endif
+		if (!ddb)
+			suspendsched();
+	}
 
 	pmf_system_shutdown(boothowto);