This is a note to let you know that I've just added the patch titled riscv: mm: add missing memcpy in kasan_init to the 6.0-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: riscv-mm-add-missing-memcpy-in-kasan_init.patch and it can be found in the queue-6.0 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 49fc7581eda99ed8d727efca4240d2cf6eb5b196 Author: Qinglin Pan <panqinglin2020@xxxxxxxxxxx> Date: Sun Oct 9 16:30:50 2022 +0800 riscv: mm: add missing memcpy in kasan_init [ 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> 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);