From: Qinglin Pan <panqinglin2020@xxxxxxxxxxx>
[ Upstream commit 9f2ac64d6ca60db99132e08628ac2899f956a0ec ]
Hi Atish,
It seems that the panic is due to the missing memcpy during kasan_init.
Could you please check whether this patch is helpful?
When doing kasan_populate, the new allocated base_pud/base_p4d should
contain kasan_early_shadow_{pud, p4d}'s content. Add the missing memcpy
to avoid page fault when read/write kasan shadow region.
Tested on:
- qemu with sv57 and CONFIG_KASAN on.
- qemu with sv48 and CONFIG_KASAN on.
Signed-off-by: Qinglin Pan <panqinglin2020@xxxxxxxxxxx>
Tested-by: Atish Patra <atishp@xxxxxxxxxxxx>
Fixes: 8fbdccd2b173 ("riscv: mm: Support kasan for sv57")
Link: https://lore.kernel.org/r/20221009083050.3814850-1-panqinglin2020@xxxxxxxxxxx
Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/riscv/mm/kasan_init.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c
index a22e418dbd82..e1226709490f 100644
--- a/arch/riscv/mm/kasan_init.c
+++ b/arch/riscv/mm/kasan_init.c
@@ -113,6 +113,8 @@ static void __init kasan_populate_pud(pgd_t *pgd,
base_pud = pt_ops.get_pud_virt(pfn_to_phys(_pgd_pfn(*pgd)));
} else if (pgd_none(*pgd)) {
base_pud = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE);
+ memcpy(base_pud, (void *)kasan_early_shadow_pud,
+ sizeof(pud_t) * PTRS_PER_PUD);
} else {
base_pud = (pud_t *)pgd_page_vaddr(*pgd);
if (base_pud == lm_alias(kasan_early_shadow_pud)) {
@@ -173,8 +175,11 @@ static void __init kasan_populate_p4d(pgd_t *pgd,
base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(*pgd)));
} else {
base_p4d = (p4d_t *)pgd_page_vaddr(*pgd);
- if (base_p4d == lm_alias(kasan_early_shadow_p4d))
+ if (base_p4d == lm_alias(kasan_early_shadow_p4d)) {
base_p4d = memblock_alloc(PTRS_PER_PUD * sizeof(p4d_t), PAGE_SIZE);
+ memcpy(base_p4d, (void *)kasan_early_shadow_p4d,
+ sizeof(p4d_t) * PTRS_PER_P4D);
+ }
}
p4dp = base_p4d + p4d_index(vaddr);
--
2.35.1
