diff -Nru /n/sources/plan9/sys/src/libmp/port/letomp.c /sys/src/libmp/port/letomp.c
--- /n/sources/plan9/sys/src/libmp/port/letomp.c	Sun Jun 15 14:03:42 2003
+++ /sys/src/libmp/port/letomp.c	Wed Jun 26 20:50:05 2024
@@ -9,8 +9,10 @@
 	int i=0, m = 0;
 	mpdigit x=0;
 
-	if(b == nil)
+	if(b == nil){
 		b = mpnew(0);
+		setmalloctag(b, getcallerpc(&s));
+	}
 	mpbits(b, 8*n);
 	for(; n > 0; n--){
 		x |= ((mpdigit)(*s++)) << i;
diff -Nru /n/sources/plan9/sys/src/libmp/port/mpaux.c /sys/src/libmp/port/mpaux.c
--- /n/sources/plan9/sys/src/libmp/port/mpaux.c	Mon Sep 19 07:19:11 2005
+++ /sys/src/libmp/port/mpaux.c	Wed Jun 26 20:54:50 2024
@@ -58,9 +58,9 @@
 		sysfatal("mpsetminbits: n < 0");
 
 	b = mallocz(sizeof(mpint), 1);
-	setmalloctag(b, getcallerpc(&n));
 	if(b == nil)
 		sysfatal("mpnew: %r");
+	setmalloctag(b, getcallerpc(&n));
 	n = DIGITS(n);
 	if(n < mpmindigits)
 		n = mpmindigits;
@@ -126,6 +126,7 @@
 	mpint *new;
 
 	new = mpnew(Dbits*old->size);
+	setmalloctag(new, getcallerpc(&old));
 	new->top = old->top;
 	new->sign = old->sign;
 	memmove(new->p, old->p, Dbytes*old->top);
diff -Nru /n/sources/plan9/sys/src/libmp/port/mprand.c /sys/src/libmp/port/mprand.c
--- /n/sources/plan9/sys/src/libmp/port/mprand.c	Sun Apr 23 17:44:05 2000
+++ /sys/src/libmp/port/mprand.c	Wed Jun 26 20:50:05 2024
@@ -11,14 +11,15 @@
 	uchar *p;
 
 	n = DIGITS(bits);
-	if(b == nil)
+	if(b == nil){
 		b = mpnew(bits);
-	else
+		setmalloctag(b, getcallerpc(&bits));
+	}else
 		mpbits(b, bits);
 
 	p = malloc(n*Dbytes);
 	if(p == nil)
-		return nil;
+		sysfatal("mprand: %r");
 	(*gen)(p, n*Dbytes);
 	betomp(p, n*Dbytes, b);
 	free(p);
diff -Nru /n/sources/plan9/sys/src/libmp/port/mptobe.c /sys/src/libmp/port/mptobe.c
--- /n/sources/plan9/sys/src/libmp/port/mptobe.c	Mon Sep 19 07:19:11 2005
+++ /sys/src/libmp/port/mptobe.c	Wed Jun 26 20:50:05 2024
@@ -15,10 +15,10 @@
 	if(p == nil){
 		n = (b->top+1)*Dbytes;
 		p = malloc(n);
+		if(p == nil)
+			sysfatal("mptobe: %r");
 		setmalloctag(p, getcallerpc(&b));
 	}
-	if(p == nil)
-		return -1;
 	if(pp != nil)
 		*pp = p;
 	memset(p, 0, n);
diff -Nru /n/sources/plan9/sys/src/libmp/port/mptoi.c /sys/src/libmp/port/mptoi.c
--- /n/sources/plan9/sys/src/libmp/port/mptoi.c	Sun Jun 15 14:04:24 2003
+++ /sys/src/libmp/port/mptoi.c	Wed Jun 26 20:50:05 2024
@@ -10,8 +10,10 @@
 mpint*
 itomp(int i, mpint *b)
 {
-	if(b == nil)
+	if(b == nil){
 		b = mpnew(0);
+		setmalloctag(b, getcallerpc(&i));
+	}
 	mpassign(mpzero, b);
 	if(i != 0)
 		b->top = 1;
diff -Nru /n/sources/plan9/sys/src/libmp/port/mptole.c /sys/src/libmp/port/mptole.c
--- /n/sources/plan9/sys/src/libmp/port/mptole.c	Sun Mar 12 14:11:14 2000
+++ /sys/src/libmp/port/mptole.c	Wed Jun 26 20:50:05 2024
@@ -16,11 +16,12 @@
 	if(p == nil){
 		n = (b->top+1)*Dbytes;
 		p = malloc(n);
+		if(p == nil)
+			sysfatal("mptole: %r");
+		setmalloctag(p, getcallerpc(&b));
 	}
 	if(pp != nil)
 		*pp = p;
-	if(p == nil)
-		return -1;
 	memset(p, 0, n);
 
 	// special case 0
diff -Nru /n/sources/plan9/sys/src/libmp/port/mptoui.c /sys/src/libmp/port/mptoui.c
--- /n/sources/plan9/sys/src/libmp/port/mptoui.c	Mon Dec 25 12:09:14 2006
+++ /sys/src/libmp/port/mptoui.c	Wed Jun 26 20:50:05 2024
@@ -10,8 +10,10 @@
 mpint*
 uitomp(uint i, mpint *b)
 {
-	if(b == nil)
+	if(b == nil){
 		b = mpnew(0);
+		setmalloctag(b, getcallerpc(&i));
+	}
 	mpassign(mpzero, b);
 	if(i != 0)
 		b->top = 1;
diff -Nru /n/sources/plan9/sys/src/libmp/port/mptouv.c /sys/src/libmp/port/mptouv.c
--- /n/sources/plan9/sys/src/libmp/port/mptouv.c	Sun Mar  5 15:45:28 2006
+++ /sys/src/libmp/port/mptouv.c	Wed Jun 26 20:50:05 2024
@@ -13,9 +13,10 @@
 {
 	int s;
 
-	if(b == nil)
+	if(b == nil){
 		b = mpnew(VLDIGITS*sizeof(mpdigit));
-	else
+		setmalloctag(b, getcallerpc(&v));
+	}else
 		mpbits(b, VLDIGITS*sizeof(mpdigit));
 	mpassign(mpzero, b);
 	if(v == 0)
diff -Nru /n/sources/plan9/sys/src/libmp/port/mptov.c /sys/src/libmp/port/mptov.c
--- /n/sources/plan9/sys/src/libmp/port/mptov.c	Thu Mar 15 21:43:46 2001
+++ /sys/src/libmp/port/mptov.c	Wed Jun 26 20:50:05 2024
@@ -14,9 +14,10 @@
 	int s;
 	uvlong uv;
 
-	if(b == nil)
+	if(b == nil){
 		b = mpnew(VLDIGITS*sizeof(mpdigit));
-	else
+		setmalloctag(b, getcallerpc(&v));
+	}else
 		mpbits(b, VLDIGITS*sizeof(mpdigit));
 	mpassign(mpzero, b);
 	if(v == 0)
diff -Nru /n/sources/plan9/sys/src/libmp/port/strtomp.c /sys/src/libmp/port/strtomp.c
--- /n/sources/plan9/sys/src/libmp/port/strtomp.c	Thu Mar 29 15:53:10 2012
+++ /sys/src/libmp/port/strtomp.c	Wed Jun 26 20:50:05 2024
@@ -160,8 +160,10 @@
 	int sign;
 	char *e;
 
-	if(b == nil)
+	if(b == nil){
 		b = mpnew(0);
+		setmalloctag(b, getcallerpc(&a));
+	}
 
 	if(tab.inited == 0)
 		init();