Re: [PATCH v5 2/2] kasan: call kasan_init_generic in kasan_init

[Christophe Leroy <christophe.leroy@csgroup.eu>]

Le 07/08/2025 à 21:40, Sabyrzhan Tasbolatov a écrit :
> Call kasan_init_generic() which handles Generic KASAN initialization.
> For architectures that do not select ARCH_DEFER_KASAN,
> this will be a no-op for the runtime flag but will
> print the initialization banner.
> 
> For SW_TAGS and HW_TAGS modes, their respective init functions will
> handle the flag enabling, if they are enabled/implemented.
> 
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217049
> Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
> Tested-by: Alexandre Ghiti <alexghiti@rivosinc.com> # riscv
> Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> # s390
> ---
> Changes in v5:
> - Unified arch patches into a single one, where we just call
> 	kasan_init_generic()
> - Added Tested-by tag for riscv (tested the same change in v4)
> - Added Acked-by tag for s390 (tested the same change in v4)
> ---
>   arch/arm/mm/kasan_init.c    | 2 +-
>   arch/arm64/mm/kasan_init.c  | 4 +---
>   arch/riscv/mm/kasan_init.c  | 1 +
>   arch/s390/kernel/early.c    | 3 ++-
>   arch/x86/mm/kasan_init_64.c | 2 +-
>   arch/xtensa/mm/kasan_init.c | 2 +-
>   6 files changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/arm/mm/kasan_init.c b/arch/arm/mm/kasan_init.c
> index 111d4f70313..c6625e808bf 100644
> --- a/arch/arm/mm/kasan_init.c
> +++ b/arch/arm/mm/kasan_init.c
> @@ -300,6 +300,6 @@ void __init kasan_init(void)
>   	local_flush_tlb_all();
>   
>   	memset(kasan_early_shadow_page, 0, PAGE_SIZE);
> -	pr_info("Kernel address sanitizer initialized\n");
>   	init_task.kasan_depth = 0;
> +	kasan_init_generic();
>   }
> diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
> index d541ce45dae..abeb81bf6eb 100644
> --- a/arch/arm64/mm/kasan_init.c
> +++ b/arch/arm64/mm/kasan_init.c
> @@ -399,14 +399,12 @@ void __init kasan_init(void)
>   {
>   	kasan_init_shadow();
>   	kasan_init_depth();
> -#if defined(CONFIG_KASAN_GENERIC)
> +	kasan_init_generic();
>   	/*
>   	 * Generic KASAN is now fully initialized.
>   	 * Software and Hardware Tag-Based modes still require
>   	 * kasan_init_sw_tags() and kasan_init_hw_tags() correspondingly.
>   	 */
> -	pr_info("KernelAddressSanitizer initialized (generic)\n");
> -#endif
>   }
>   
>   #endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
> diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c
> index 41c635d6aca..ba2709b1eec 100644
> --- a/arch/riscv/mm/kasan_init.c
> +++ b/arch/riscv/mm/kasan_init.c
> @@ -530,6 +530,7 @@ void __init kasan_init(void)
>   
>   	memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE);
>   	init_task.kasan_depth = 0;
> +	kasan_init_generic();

I understood KASAN is really ready to function only once the csr_write() 
and local_flush_tlb_all() below are done. Shouldn't kasan_init_generic() 
be called after it ?

>   
>   	csr_write(CSR_SATP, PFN_DOWN(__pa(swapper_pg_dir)) | satp_mode);
>   	local_flush_tlb_all();
> diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
> index 9adfbdd377d..544e5403dd9 100644
> --- a/arch/s390/kernel/early.c
> +++ b/arch/s390/kernel/early.c
> @@ -21,6 +21,7 @@
>   #include <linux/kernel.h>
>   #include <asm/asm-extable.h>
>   #include <linux/memblock.h>
> +#include <linux/kasan.h>
>   #include <asm/access-regs.h>
>   #include <asm/asm-offsets.h>
>   #include <asm/machine.h>
> @@ -65,7 +66,7 @@ static void __init kasan_early_init(void)
>   {
>   #ifdef CONFIG_KASAN
>   	init_task.kasan_depth = 0;
> -	pr_info("KernelAddressSanitizer initialized\n");
> +	kasan_init_generic();
>   #endif
>   }
>   
> diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
> index 0539efd0d21..998b6010d6d 100644
> --- a/arch/x86/mm/kasan_init_64.c
> +++ b/arch/x86/mm/kasan_init_64.c
> @@ -451,5 +451,5 @@ void __init kasan_init(void)
>   	__flush_tlb_all();
>   
>   	init_task.kasan_depth = 0;
> -	pr_info("KernelAddressSanitizer initialized\n");
> +	kasan_init_generic();
>   }
> diff --git a/arch/xtensa/mm/kasan_init.c b/arch/xtensa/mm/kasan_init.c
> index f39c4d83173..0524b9ed5e6 100644
> --- a/arch/xtensa/mm/kasan_init.c
> +++ b/arch/xtensa/mm/kasan_init.c
> @@ -94,5 +94,5 @@ void __init kasan_init(void)
>   
>   	/* At this point kasan is fully initialized. Enable error messages. */
>   	current->kasan_depth = 0;
> -	pr_info("KernelAddressSanitizer initialized\n");
> +	kasan_init_generic();
>   }