riscv: Fix config KASAN && SPARSEMEM && !SPARSE_VMEMMAP

In order to get the pfn of a struct page* when sparsemem is enabled
without vmemmap, the mem_section structures need to be initialized which
happens in sparse_init.

But kasan_early_init calls pfn_to_page way before sparse_init is called,
which then tries to dereference a null mem_section pointer.

Fix this by removing the usage of this function in kasan_early_init.

Fixes: 8ad8b72721d0 ("riscv: Add KASAN support")
Signed-off-by: Alexandre Ghiti <alexandre.ghiti@canonical.com>
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c
index f61f7ca..85e8493 100644 (file)
--- a/arch/riscv/mm/kasan_init.c
+++ b/arch/riscv/mm/kasan_init.c
@@ -202,8 +202,7 @@ asmlinkage void __init kasan_early_init(void)
 
        for (i = 0; i < PTRS_PER_PTE; ++i)
                set_pte(kasan_early_shadow_pte + i,
-                       mk_pte(virt_to_page(kasan_early_shadow_page),
-                              PAGE_KERNEL));
+                       pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL));
 
        for (i = 0; i < PTRS_PER_PMD; ++i)
                set_pmd(kasan_early_shadow_pmd + i,