From 0ce7909cd0ba35148bddd8309534cb96e9e20f48 Mon Sep 17 00:00:00 2001
From: Doug Moore <dougm@FreeBSD.org>
Date: Wed, 19 Jan 2022 00:42:39 -0600
Subject: [PATCH] vm_phys: add essential segment bounds check

A lower-bound segment check is necessary in vm_phys_alloc_seg_contig.
Add one.

Reported by:	jenkins
Reviewed by:	alc
Fixes:	da92ecbc0d8f vm_phys: fix seg->end test in alloc_seg_contig
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D33945
---
 sys/vm/vm_phys.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sys/vm/vm_phys.c b/sys/vm/vm_phys.c
index a880b7abd324..7ca3f5fbc0c5 100644
--- a/sys/vm/vm_phys.c
+++ b/sys/vm/vm_phys.c
@@ -1451,7 +1451,8 @@ vm_phys_alloc_seg_contig(struct vm_phys_seg *seg, u_long npages,
 				 * (without overflow in pa_end calculation)
 				 * and fits within the segment.
 				 */
-				if (pa_end < pa || pa_end > seg->end)
+				if (pa_end < pa ||
+				    pa < seg->start || seg->end < pa_end)
 					continue;
 
 				/*