[v5] mm/kasan: make kasan=on|off work for all three modes

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

Posted by Baoquan He 1 month, 1 week ago

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;
-- 
2.52.0

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

Posted by Sourabh Jain 3 weeks, 4 days ago


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

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

Posted by Christophe Leroy (CS GROUP) 3 weeks, 4 days ago


Le 12/03/2026 à 12:12, Sourabh Jain a écrit :
> 
> 
> 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.

When KASAN is enabled it is advertised with:

	pr_info("KernelAddressSanitizer initialized (generic)\n");

Isn't the absence of that message enough to understand KASAN is not there ?

> 
> $ 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
>

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

Posted by Sourabh Jain 3 weeks ago


On 12/03/26 16:53, Christophe Leroy (CS GROUP) wrote:
>
>
> Le 12/03/2026 à 12:12, Sourabh Jain a écrit :
>>
>>
>> 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.
>
> When KASAN is enabled it is advertised with:
>
>     pr_info("KernelAddressSanitizer initialized (generic)\n");
>
> Isn't the absence of that message enough to understand KASAN is not 
> there ?

Yes this should work. Thanks.


- Sourabh Jain


>
>>
>> $ 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
>>
>

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

Posted by Baoquan He 3 weeks ago

On 03/12/26 at 12:23pm, Christophe Leroy (CS GROUP) wrote:
> 
> 
> Le 12/03/2026 à 12:12, Sourabh Jain a écrit :
> > 
> > 
> > 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.
> 
> When KASAN is enabled it is advertised with:
> 
> 	pr_info("KernelAddressSanitizer initialized (generic)\n");
> 
> Isn't the absence of that message enough to understand KASAN is not there ?

Right, that's the way I took when I tested it.

> 
> > 
> > $ 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>

Thanks for testing.