For memblock_cap_memory_range() to work properly, it should be called
after memory is detected and added to memblock with memblock_add() or
memblock_add_node(). If memblock_cap_memory_range() would be called
before memory is registered, we may silently corrupt memory later
because the crash kernel will see all memory as available.
Print a warning and bail out if ordering is not satisfied.
Suggested-by: Mike Rapoport <rppt@xxxxxxxxxx>
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
mm/memblock.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/mm/memblock.c b/mm/memblock.c
index 57a9849a5d820c34..e2ca8ddc8ebebf4e 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1685,6 +1685,11 @@ void __init memblock_cap_memory_range(phys_addr_t base, phys_addr_t size)
if (!size)
return;
+ if (memblock.memory.cnt <= 1) {
+ pr_warn("%s: No memory registered yet\n", __func__);
+ return;
+ }
+
ret = memblock_isolate_range(&memblock.memory, base, size,
&start_rgn, &end_rgn);
if (ret)
--
2.25.1
