Subject: [PATCH] kasan: add kasan mode messages when kasan init

There are multiple kasan modes. It make sense that we add some messages
to know which kasan mode is when booting up. see [1].

Link: https://bugzilla.kernel.org/show_bug.cgi?id=212195 [1]
Signed-off-by: Kuan-Ying Lee <[email protected]>
---
arch/arm64/mm/kasan_init.c | 2 +-
mm/kasan/hw_tags.c | 4 +++-
mm/kasan/sw_tags.c | 2 +-
3 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
index 61b52a92b8b6..b4e78beac285 100644
--- a/arch/arm64/mm/kasan_init.c
+++ b/arch/arm64/mm/kasan_init.c
@@ -293,7 +293,7 @@ void __init kasan_init(void)
kasan_init_depth();
#if defined(CONFIG_KASAN_GENERIC)
/* CONFIG_KASAN_SW_TAGS also requires kasan_init_sw_tags(). */
- pr_info("KernelAddressSanitizer initialized\n");
+ pr_info("KernelAddressSanitizer initialized (generic)\n");
#endif
}

diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
index 05d1e9460e2e..3e28ecbe1d8f 100644
--- a/mm/kasan/hw_tags.c
+++ b/mm/kasan/hw_tags.c
@@ -168,7 +168,9 @@ void __init kasan_init_hw_tags(void)
break;
}

- pr_info("KernelAddressSanitizer initialized\n");
+ pr_info("KernelAddressSanitizer initialized (hw-tags, mode=%s, stacktrace=%s)\n",
+ kasan_flag_async ? "async" : "sync",
+ kasan_stack_collection_enabled() ? "on" : "off");
}

void kasan_alloc_pages(struct page *page, unsigned int order, gfp_t flags)
diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c
index bd3f540feb47..77f13f391b57 100644
--- a/mm/kasan/sw_tags.c
+++ b/mm/kasan/sw_tags.c
@@ -42,7 +42,7 @@ void __init kasan_init_sw_tags(void)
for_each_possible_cpu(cpu)
per_cpu(prng_state, cpu) = (u32)get_cycles();

- pr_info("KernelAddressSanitizer initialized\n");
+ pr_info("KernelAddressSanitizer initialized (sw-tags)\n");
}

/*
--
2.18.0


2021-10-19 14:16:58

by Marco Elver

[permalink] [raw]
Subject: Re: [PATCH] kasan: add kasan mode messages when kasan init

On Tue, 19 Oct 2021 at 14:04, Kuan-Ying Lee <[email protected]> wrote:
>
> There are multiple kasan modes. It make sense that we add some messages
> to know which kasan mode is when booting up. see [1].
>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=212195 [1]
> Signed-off-by: Kuan-Ying Lee <[email protected]>

Looks good, however, you need to rebase to -next because of "kasan:
Extend KASAN mode kernel parameter"...

> ---
> arch/arm64/mm/kasan_init.c | 2 +-
> mm/kasan/hw_tags.c | 4 +++-
> mm/kasan/sw_tags.c | 2 +-
> 3 files changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
> index 61b52a92b8b6..b4e78beac285 100644
> --- a/arch/arm64/mm/kasan_init.c
> +++ b/arch/arm64/mm/kasan_init.c
> @@ -293,7 +293,7 @@ void __init kasan_init(void)
> kasan_init_depth();
> #if defined(CONFIG_KASAN_GENERIC)
> /* CONFIG_KASAN_SW_TAGS also requires kasan_init_sw_tags(). */
> - pr_info("KernelAddressSanitizer initialized\n");
> + pr_info("KernelAddressSanitizer initialized (generic)\n");
> #endif
> }
>
> diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
> index 05d1e9460e2e..3e28ecbe1d8f 100644
> --- a/mm/kasan/hw_tags.c
> +++ b/mm/kasan/hw_tags.c
> @@ -168,7 +168,9 @@ void __init kasan_init_hw_tags(void)
> break;
> }
>
> - pr_info("KernelAddressSanitizer initialized\n");
> + pr_info("KernelAddressSanitizer initialized (hw-tags, mode=%s, stacktrace=%s)\n",
> + kasan_flag_async ? "async" : "sync",

... which means this will have a 3rd option "asymm".

> + kasan_stack_collection_enabled() ? "on" : "off");
> }
>
> void kasan_alloc_pages(struct page *page, unsigned int order, gfp_t flags)
> diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c
> index bd3f540feb47..77f13f391b57 100644
> --- a/mm/kasan/sw_tags.c
> +++ b/mm/kasan/sw_tags.c
> @@ -42,7 +42,7 @@ void __init kasan_init_sw_tags(void)
> for_each_possible_cpu(cpu)
> per_cpu(prng_state, cpu) = (u32)get_cycles();
>
> - pr_info("KernelAddressSanitizer initialized\n");
> + pr_info("KernelAddressSanitizer initialized (sw-tags)\n");
> }
>
> /*
> --
> 2.18.0

Subject: Re: [PATCH] kasan: add kasan mode messages when kasan init

On Tue, 2021-10-19 at 22:14 +0800, Marco Elver wrote:
> On Tue, 19 Oct 2021 at 14:04, Kuan-Ying Lee <
> [email protected]> wrote:
> >
> > There are multiple kasan modes. It make sense that we add some
> > messages
> > to know which kasan mode is when booting up. see [1].
> >
> > Link:
> > https://urldefense.com/v3/__https://bugzilla.kernel.org/show_bug.cgi?id=212195__;!!CTRNKA9wMg0ARbw!374SjX0W47zTqp1xJyIg9CW0T7ggAT1rr981lIRBjQhUk2_495ltG_ZkiW6jmeVDBvu_UA$
> > $ [1]
> > Signed-off-by: Kuan-Ying Lee <[email protected]>
>
> Looks good, however, you need to rebase to -next because of "kasan:
> Extend KASAN mode kernel parameter"...

Thanks Marco.
I will send the v2.

>
> > ---
> > arch/arm64/mm/kasan_init.c | 2 +-
> > mm/kasan/hw_tags.c | 4 +++-
> > mm/kasan/sw_tags.c | 2 +-
> > 3 files changed, 5 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/arm64/mm/kasan_init.c
> > b/arch/arm64/mm/kasan_init.c
> > index 61b52a92b8b6..b4e78beac285 100644
> > --- a/arch/arm64/mm/kasan_init.c
> > +++ b/arch/arm64/mm/kasan_init.c
> > @@ -293,7 +293,7 @@ void __init kasan_init(void)
> > kasan_init_depth();
> > #if defined(CONFIG_KASAN_GENERIC)
> > /* CONFIG_KASAN_SW_TAGS also requires kasan_init_sw_tags().
> > */
> > - pr_info("KernelAddressSanitizer initialized\n");
> > + pr_info("KernelAddressSanitizer initialized (generic)\n");
> > #endif
> > }
> >
> > diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
> > index 05d1e9460e2e..3e28ecbe1d8f 100644
> > --- a/mm/kasan/hw_tags.c
> > +++ b/mm/kasan/hw_tags.c
> > @@ -168,7 +168,9 @@ void __init kasan_init_hw_tags(void)
> > break;
> > }
> >
> > - pr_info("KernelAddressSanitizer initialized\n");
> > + pr_info("KernelAddressSanitizer initialized (hw-tags,
> > mode=%s, stacktrace=%s)\n",
> > + kasan_flag_async ? "async" : "sync",
>
> ... which means this will have a 3rd option "asymm".

Thanks for the reminder.

>
> > + kasan_stack_collection_enabled() ? "on" : "off");
> > }
> >
> > void kasan_alloc_pages(struct page *page, unsigned int order,
> > gfp_t flags)
> > diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c
> > index bd3f540feb47..77f13f391b57 100644
> > --- a/mm/kasan/sw_tags.c
> > +++ b/mm/kasan/sw_tags.c
> > @@ -42,7 +42,7 @@ void __init kasan_init_sw_tags(void)
> > for_each_possible_cpu(cpu)
> > per_cpu(prng_state, cpu) = (u32)get_cycles();
> >
> > - pr_info("KernelAddressSanitizer initialized\n");
> > + pr_info("KernelAddressSanitizer initialized (sw-tags)\n");
> > }
> >
> > /*
> > --
> > 2.18.0
>
>