svn commit: r332962 - head/sys/kern

[Conrad Meyer]

Author: cem
Date: Tue Apr 24 19:10:51 2018
New Revision: 332962
URL: https://svnweb.freebsd.org/changeset/base/332962

Log:
  Do not totally silence suppressed secondary kasserts unless debug.kassert.do_log is disabled
  
  To totally silence and ignore secondary kassert violations after a primary
  panic, set debug.kassert.do_log=0 and debug.kassert.suppress_in_panic=1.
  
  Additional assertion warnings shouldn't block core dump and may alert the
  developer to another erroneous condition.  Secondary stack traces may be
  printed, identically to the unsuppressed case where panic() is reentered --
  controlled via debug.trace_all_panics.
  
  Sponsored by:	Dell EMC Isilon

Modified:
  head/sys/kern/kern_shutdown.c

Modified: head/sys/kern/kern_shutdown.c
==============================================================================
--- head/sys/kern/kern_shutdown.c	Tue Apr 24 19:09:53 2018	(r332961)
+++ head/sys/kern/kern_shutdown.c	Tue Apr 24 19:10:51 2018	(r332962)
@@ -718,13 +718,24 @@ kassert_panic(const char *fmt, ...)
 	static char buf[256];
 	va_list ap;
 
-	/* If we already panic'd, don't create a double-fault. */
-	if (panicstr != NULL && kassert_suppress_in_panic)
-		return;
-
 	va_start(ap, fmt);
 	(void)vsnprintf(buf, sizeof(buf), fmt, ap);
 	va_end(ap);
+
+	/*
+	 * If we are suppressing secondary panics, log the warning but do not
+	 * re-enter panic/kdb.
+	 */
+	if (panicstr != NULL && kassert_suppress_in_panic) {
+		if (kassert_do_log) {
+			printf("KASSERT failed: %s\n", buf);
+#ifdef KDB
+			if (trace_all_panics && trace_on_panic)
+				kdb_backtrace();
+#endif
+		}
+		return;
+	}
 
 	/*
 	 * panic if we're not just warning, or if we've exceeded