powerpc/32: Reuse orphaned memblocks in kasan_init_shadow_page_tables()

If concurrent PMD population has happened, re-use orphaned memblocks.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b29ffffb9206dc14541fa420c17604240728041b.1579024426.git.christophe.leroy@c-s.fr

diff --git a/arch/powerpc/mm/kasan/kasan_init_32.c b/arch/powerpc/mm/kasan/kasan_init_32.c
index c4bf9ed04f8822f452cfa7bd7922285e6065dfad..d3cacd4625605a4b6c855b620c5c76ca973bc83d 100644 (file)
--- a/arch/powerpc/mm/kasan/kasan_init_32.c
+++ b/arch/powerpc/mm/kasan/kasan_init_32.c
@@ -34,17 +34,17 @@ static int __init kasan_init_shadow_page_tables(unsigned long k_start, unsigned
 {
        pmd_t *pmd;
        unsigned long k_cur, k_next;
+       pte_t *new = NULL;
 
        pmd = pmd_offset(pud_offset(pgd_offset_k(k_start), k_start), k_start);
 
        for (k_cur = k_start; k_cur != k_end; k_cur = k_next, pmd++) {
-               pte_t *new;
-
                k_next = pgd_addr_end(k_cur, k_end);
                if ((void *)pmd_page_vaddr(*pmd) != kasan_early_shadow_pte)
                        continue;
 
-               new = memblock_alloc(PTE_FRAG_SIZE, PTE_FRAG_SIZE);
+               if (!new)
+                       new = memblock_alloc(PTE_FRAG_SIZE, PTE_FRAG_SIZE);
 
                if (!new)
                        return -ENOMEM;