svn commit: r339917 - head/sys/kern

[Eric van Gyzen]

Author: vangyzen
Date: Tue Oct 30 14:54:15 2018
New Revision: 339917
URL: https://svnweb.freebsd.org/changeset/base/339917

Log:
  Always stop the scheduler when entering kdb
  
  Set curthread->td_stopsched when entering kdb via any vector.
  Previously, it was only set when entering via panic, so when
  entering kdb another way, mutexes and such were still "live",
  and an attempt to lock an already locked mutex would panic.
  
  Reviewed by:	kib, cem
  Discussed with:	jhb
  Tested by:	pho
  MFC after:	2 months
  Sponsored by:	Dell EMC Isilon
  Differential Revision:	https://reviews.freebsd.org/D17687

Modified:
  head/sys/kern/subr_kdb.c

Modified: head/sys/kern/subr_kdb.c
==============================================================================
--- head/sys/kern/subr_kdb.c	Tue Oct 30 14:44:12 2018	(r339916)
+++ head/sys/kern/subr_kdb.c	Tue Oct 30 14:54:15 2018	(r339917)
@@ -652,9 +652,7 @@ kdb_trap(int type, int code, struct trapframe *tf)
 	struct kdb_dbbe *be;
 	register_t intr;
 	int handled;
-#ifdef SMP
 	int did_stop_cpus;
-#endif
 
 	be = kdb_dbbe;
 	if (be == NULL || be->dbbe_trap == NULL)
@@ -666,16 +664,17 @@ kdb_trap(int type, int code, struct trapframe *tf)
 
 	intr = intr_disable();
 
-#ifdef SMP
 	if (!SCHEDULER_STOPPED()) {
+#ifdef SMP
 		other_cpus = all_cpus;
 		CPU_NAND(&other_cpus, &stopped_cpus);
 		CPU_CLR(PCPU_GET(cpuid), &other_cpus);
 		stop_cpus_hard(other_cpus);
+#endif
+		curthread->td_stopsched = 1;
 		did_stop_cpus = 1;
 	} else
 		did_stop_cpus = 0;
-#endif
 
 	kdb_active++;
 
@@ -703,12 +702,13 @@ kdb_trap(int type, int code, struct trapframe *tf)
 
 	kdb_active--;
 
-#ifdef SMP
 	if (did_stop_cpus) {
+		curthread->td_stopsched = 0;
+#ifdef SMP
 		CPU_AND(&other_cpus, &stopped_cpus);
 		restart_cpus(other_cpus);
-	}
 #endif
+	}
 
 	intr_restore(intr);