kho: kho_restore_vmalloc: fix initialization of pages array

Patch series "kho: fixes for vmalloc restoration".

Pratyush reported off-list that when kho_restore_vmalloc() is used to
restore a vmalloc_huge() allocation it hits VM_BUG_ON() when we
reconstruct the struct pages in kho_restore_pages().

These patches fix the issue.


This patch (of 2):

In case a preserved vmalloc allocation was using huge pages, all pages in
the array of pages added to vm_struct during kho_restore_vmalloc() are
wrongly set to the same page.

Fix the indexing when assigning pages to that array.

Link: https://lkml.kernel.org/r/20251125110917.843744-1-rppt@kernel.org
Link: https://lkml.kernel.org/r/20251125110917.843744-2-rppt@kernel.org
Fixes: a667300 ("kho: add support for preserving vmalloc allocations")
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: rppt

kernel/liveupdate/kexec_handover.c

@@ -1096,7 +1096,7 @@ void *kho_restore_vmalloc(const struct kho_vmalloc *preservation)
 				goto err_free_pages_array;
 
 			for (int j = 0; j < contig_pages; j++)
-				pages[idx++] = page;
+				pages[idx++] = page + j;
 
 			phys += contig_pages * PAGE_SIZE;
 		}