2 files changed, 12 insertions, 4 deletions

diff --git a/sys/amd64/amd64/dump_machdep.c b/sys/amd64/amd64/dump_machdep.c
index 9130139049a8..e80489ff755b 100644
--- a/sys/amd64/amd64/dump_machdep.c
+++ b/sys/amd64/amd64/dump_machdep.c
@@ -177,6 +177,7 @@ cb_dumpdata(struct md_pa *mdp, int seqnr, void *arg)
 	uint64_t pgs;
 	size_t counter, sz, chunk;
 	int i, c, error, twiddle;
+	u_int maxdumppgs;
 
 	error = 0;	/* catch case in which chunk size is 0 */
 	counter = 0;	/* Update twiddle every 16MB */
@@ -184,13 +185,16 @@ cb_dumpdata(struct md_pa *mdp, int seqnr, void *arg)
 	va = 0;
 	pgs = mdp->md_size / PAGE_SIZE;
 	pa = mdp->md_start;
+	maxdumppgs = di->maxiosize / PAGE_SIZE;
+	if (maxdumppgs == 0)	/* seatbelt */
+		maxdumppgs = 1;
 
 	printf("  chunk %d: %ldMB (%ld pages)", seqnr, PG2MB(pgs), pgs);
 
 	while (pgs) {
 		chunk = pgs;
-		if (chunk > MAXDUMPPGS)
-			chunk = MAXDUMPPGS;
+		if (chunk > maxdumppgs)
+			chunk = maxdumppgs;
 		sz = chunk << PAGE_SHIFT;
 		counter += sz;
 		if (counter >> 24) {
diff --git a/sys/amd64/amd64/minidump_machdep.c b/sys/amd64/amd64/minidump_machdep.c
index 943c5e66a557..4c3333dc0978 100644
--- a/sys/amd64/amd64/minidump_machdep.c
+++ b/sys/amd64/amd64/minidump_machdep.c
@@ -122,7 +122,11 @@ blk_write(struct dumperinfo *di, char *ptr, vm_paddr_t pa, size_t sz)
 {
 	size_t len;
 	int error, i, c;
+	u_int maxdumpsz;
 
+	maxdumpsz = di->maxiosize;
+	if (maxdumpsz == 0)	/* seatbelt */
+		maxdumpsz = PAGE_SIZE;
 	error = 0;
 	if ((sz % PAGE_SIZE) != 0) {
 		printf("size not page aligned\n");
@@ -143,7 +147,7 @@ blk_write(struct dumperinfo *di, char *ptr, vm_paddr_t pa, size_t sz)
 			return (error);
 	}
 	while (sz) {
-		len = (MAXDUMPPGS * PAGE_SIZE) - fragsz;
+		len = maxdumpsz - fragsz;
 		if (len > sz)
 			len = sz;
 		counter += len;
@@ -165,7 +169,7 @@ blk_write(struct dumperinfo *di, char *ptr, vm_paddr_t pa, size_t sz)
 			fragsz += len;
 			pa += len;
 			sz -= len;
-			if (fragsz == (MAXDUMPPGS * PAGE_SIZE)) {
+			if (fragsz == maxdumpsz) {
 				error = blk_flush(di);
 				if (error)
 					return (error);