When INVARIANTS is defined make sure that uma_zalloc_arg (and hence

uma_zalloc) is called with exactly one of either M_WAITOK or M_NOWAIT and
that it is called with neither M_TRYWAIT or M_DONTWAIT. Print a warning
if anything is wrong. Default to M_WAITOK of no flag is given. This is the
same test as in malloc(9).

1 files changed, 20 insertions, 0 deletions

diff --git a/sys/vm/uma_core.c b/sys/vm/uma_core.c
index fba9474..d887f3c 100644
--- a/sys/vm/uma_core.c
+++ b/sys/vm/uma_core.c
@@ -68,6 +68,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/proc.h>
 #include <sys/smp.h>
 #include <sys/vmmeter.h>
+#include <sys/mbuf.h>
 
 #include <vm/vm.h>
 #include <vm/vm_object.h>
@@ -1320,6 +1321,25 @@ uma_zalloc_arg(uma_zone_t zone, void *udata, int flags)
 	printf("Allocating one item from %s(%p)\n", zone->uz_name, zone);
 #endif
 
+#ifdef INVARIANTS
+	/*
+	 * To make sure that WAITOK or NOWAIT is set, but not more than
+	 * one, and check against the API botches that are common.
+	 * The uma code implies M_WAITOK if M_NOWAIT is not set, so
+	 * we default to waiting if none of the flags is set.
+	 */
+	cpu = flags & (M_WAITOK | M_NOWAIT | M_DONTWAIT | M_TRYWAIT);
+	if (cpu != M_NOWAIT && cpu != M_WAITOK) {
+		static	struct timeval lasterr;
+		static	int curerr, once;
+		if (once == 0 && ppsratecheck(&lasterr, &curerr, 1)) {
+			printf("Bad uma_zalloc flags: %x\n", cpu);
+			backtrace();
+			once++;
+		}
+	}
+#endif
+
 	if (!(flags & M_NOWAIT)) {
 		KASSERT(curthread->td_intr_nesting_level == 0,
 		   ("malloc(M_WAITOK) in interrupt context"));