git: f106887cb0aa - stable/14 - vm_phys: Check for overlap when adding a segment

The branch stable/14 has been updated by olce:

URL: https://cgit.FreeBSD.org/src/commit/?id=f106887cb0aa502a23f353d3c75dc60ec1ce1668

commit f106887cb0aa502a23f353d3c75dc60ec1ce1668
Author:     Olivier Certner <olce@FreeBSD.org>
AuthorDate: 2024-10-10 07:41:40 +0000
Commit:     Olivier Certner <olce@FreeBSD.org>
CommitDate: 2025-04-08 13:38:21 +0000

    vm_phys: Check for overlap when adding a segment
    
    Segments are passed by machine-dependent routines, so explicit checks
    will make debugging much easier on very weird machines or when someone
    is tweaking these machine-dependent routines.  Additionally, this
    operation is not performance-sensitive.
    
    For the same reasons, test that we don't reach the maximum number of
    physical segments (the compile-time of the internal storage) in
    production kernels (replaces the existing KASSERT()).
    
    Reviewed by:    markj
    MFC after:      1 week
    Sponsored by:   The FreeBSD Foundation
    Differential Revision:  https://reviews.freebsd.org/D48628
    
    (cherry picked from commit 8a14ddcc1d8e4384d8ad77c5536c916c6e9a7d65)
---
 sys/vm/vm_phys.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/sys/vm/vm_phys.c b/sys/vm/vm_phys.c
index 98ea22fd2b9d..3f8c37b4c2bf 100644
--- a/sys/vm/vm_phys.c
+++ b/sys/vm/vm_phys.c
@@ -403,18 +403,26 @@ _vm_phys_create_seg(vm_paddr_t start, vm_paddr_t end, int domain)
 {
 	struct vm_phys_seg *seg;
 
-	KASSERT(vm_phys_nsegs < VM_PHYSSEG_MAX,
-	    ("vm_phys_create_seg: increase VM_PHYSSEG_MAX"));
-	KASSERT(domain >= 0 && domain < vm_ndomains,
-	    ("vm_phys_create_seg: invalid domain provided"));
+	if (!(0 <= domain && domain < vm_ndomains))
+		panic("%s: Invalid domain %d ('vm_ndomains' is %d)",
+		    __func__, domain, vm_ndomains);
+	if (vm_phys_nsegs >= VM_PHYSSEG_MAX)
+		panic("Not enough storage for physical segments, "
+		    "increase VM_PHYSSEG_MAX");
+
 	seg = &vm_phys_segs[vm_phys_nsegs++];
-	while (seg > vm_phys_segs && (seg - 1)->start >= end) {
+	while (seg > vm_phys_segs && seg[-1].start >= end) {
 		*seg = *(seg - 1);
 		seg--;
 	}
 	seg->start = start;
 	seg->end = end;
 	seg->domain = domain;
+	if (seg != vm_phys_segs && seg[-1].end > start)
+		panic("Overlapping physical segments: Current [%#jx,%#jx) "
+		    "at index %zu, previous [%#jx,%#jx)",
+		    (uintmax_t)start, (uintmax_t)end, seg - vm_phys_segs,
+		    (uintmax_t)seg[-1].start, (uintmax_t)seg[-1].end);
 }
 
 static void