[PATCH] kho: Don't release incoming bootmem areas when kho_init() fails

[Chris Down <chris@chrisdown.name>]

kho_populate() adds the incoming bootmem areas without reserving
them. memblock_free_all() then hands the remainder to the buddy
allocator.

Unfortunately however, if kho_init() fails, err_free_bootmem
currently frees every area with free_reserved_area(). This can free
pages still backing early allocations or free buddy pages a second
time.

To fix this, let's only free the areas on a cold boot when
kho_reserve_bootmem() reserved them.

Fixes: c609c144b0e8 ("kexec: add KHO parsing support")
Cc: <stable@vger.kernel.org>
Signed-off-by: Chris Down <chris@chrisdown.name>
---
 kernel/liveupdate/kexec_handover.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c
index 6f1f55fe3181..a566ad6634d8 100644
--- a/kernel/liveupdate/kexec_handover.c
+++ b/kernel/liveupdate/kexec_handover.c
@@ -1899,11 +1899,13 @@ static __init int kho_init(void)
 	kho_radix_destroy_tree(tree);
 err_free_bootmem:
 	kho_out.fdt = NULL;
-	for (int i = 0; i < kho_bootmem_cnt; i++) {
-		void *start = __va(kho_bootmem[i].addr);
-		void *end = start + kho_bootmem[i].size;
+	if (!fdt) {
+		for (int i = 0; i < kho_bootmem_cnt; i++) {
+			void *start = __va(kho_bootmem[i].addr);
+			void *end = start + kho_bootmem[i].size;
 
-		free_reserved_area(start, end, -1, "");
+			free_reserved_area(start, end, -1, "");
+		}
 	}
 	kho_enable = false;
 	return err;

base-commit: fa4ad798f6f681031775266044ba1b0cf3c670bd
-- 
2.54.0