Re: [PATCH v5 09/15] arch/powerpc: don't initialize kasan if it's disabled

Sourabh Jain
2026-03-12T11:13:12Z

On 25/02/26 13:44, Baoquan He wrote:
> Here, kasan is disabled if specified 'kasan=off' in kernel cmdline.
>
> This includes 32bit, book3s/64 and book3e/64.
>
> Signed-off-by: Baoquan He <bhe@redhat.com>
> Cc: linuxppc-dev@lists.ozlabs.org
> ---
> arch/powerpc/mm/kasan/init_32.c | 6 +++++-
> arch/powerpc/mm/kasan/init_book3e_64.c | 4 ++++
> arch/powerpc/mm/kasan/init_book3s_64.c | 4 ++++
> 3 files changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/mm/kasan/init_32.c b/arch/powerpc/mm/kasan/init_32.c
> index 1d083597464f..0ea2a636c992 100644
> --- a/arch/powerpc/mm/kasan/init_32.c
> +++ b/arch/powerpc/mm/kasan/init_32.c
> @@ -141,6 +141,10 @@ void __init kasan_init(void)
> u64 i;
> int ret;
>
> + /* If KASAN is disabled via command line, don't initialize it. */
> + if (kasan_arg_disabled)
> + return;
> +
> for_each_mem_range(i, &base, &end) {
> phys_addr_t top = min(end, total_lowmem);
>
> @@ -170,7 +174,7 @@ void __init kasan_init(void)
>
> void __init kasan_late_init(void)
> {
> - if (IS_ENABLED(CONFIG_KASAN_VMALLOC))
> + if (IS_ENABLED(CONFIG_KASAN_VMALLOC) && kasan_enabled())
> kasan_unmap_early_shadow_vmalloc();
> }
>
> diff --git a/arch/powerpc/mm/kasan/init_book3e_64.c b/arch/powerpc/mm/kasan/init_book3e_64.c
> index 0d3a73d6d4b0..fbe4c9a7e460 100644
> --- a/arch/powerpc/mm/kasan/init_book3e_64.c
> +++ b/arch/powerpc/mm/kasan/init_book3e_64.c
> @@ -111,6 +111,10 @@ void __init kasan_init(void)
> u64 i;
> pte_t zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL_RO);
>
> + /* If KASAN is disabled via command line, don't initialize it. */
> + if (kasan_arg_disabled)
> + return;
> +
> for_each_mem_range(i, &start, &end)
> kasan_init_phys_region(phys_to_virt(start), phys_to_virt(end));
>
> diff --git a/arch/powerpc/mm/kasan/init_book3s_64.c b/arch/powerpc/mm/kasan/init_book3s_64.c
> index dcafa641804c..f7906f9ef9be 100644
> --- a/arch/powerpc/mm/kasan/init_book3s_64.c
> +++ b/arch/powerpc/mm/kasan/init_book3s_64.c
> @@ -54,6 +54,10 @@ void __init kasan_init(void)
> u64 i;
> pte_t zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL);
>
> + /* If KASAN is disabled via command line, don't initialize it. */
> + if (kasan_arg_disabled)
> + return;
> +
> if (!early_radix_enabled()) {
> pr_warn("KASAN not enabled as it requires radix!");
> return;

Should we log in the kernel log buffer that KASAN is disabled?

Right now, I don't see the kernel advertising the same.

$ dmesg | grep -i kasan
[    0.000000] Kernel command line:
BOOT_IMAGE=(ieee1275//vdevice/v-scsi@30000070/disk@8100000000000000,msdos2)/vmlinuz-7.0.0-rc3+
crashkernel=2G kasan=off

Tested this series on powerpc Pseries platform.
So feel free to add:
Tested-by: Sourabh Jain <sourabhjain@linux.ibm.com>

- Sourabh Jain