Re: [PATCH] powerpc/lib: fix book3s/32 boot failure due to code patching

Re: [PATCH] powerpc/lib: fix book3s/32 boot failure due to code patching

[Christophe Leroy]

Oops, forgot to tell it's for 4.9. Resending with proper subject.

Le 15/05/2019 à 08:39, Christophe Leroy a écrit :
> [Backport of upstream commit b45ba4a51cde29b2939365ef0c07ad34c8321789]
> 
> On powerpc32, patch_instruction() is called by apply_feature_fixups()
> which is called from early_init()
> 
> There is the following note in front of early_init():
>   * Note that the kernel may be running at an address which is different
>   * from the address that it was linked at, so we must use RELOC/PTRRELOC
>   * to access static data (including strings).  -- paulus
> 
> Therefore init_mem_is_free must be accessed with PTRRELOC()
> 
> Fixes: 1c38a84d4586 ("powerpc: Avoid code patching freed init sections")
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=203597
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> 
> ---
> Can't apply the upstream commit as such due to several other unrelated stuff
> like for instance STRICT_KERNEL_RWX which are missing.
> So instead, using same approach as for commit 252eb55816a6f69ef9464cad303cdb3326cdc61d
> ---
>   arch/powerpc/lib/code-patching.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
> index 14535ad4cdd1..c312955977ce 100644
> --- a/arch/powerpc/lib/code-patching.c
> +++ b/arch/powerpc/lib/code-patching.c
> @@ -23,7 +23,7 @@ int patch_instruction(unsigned int *addr, unsigned int instr)
>   	int err;
>   
>   	/* Make sure we aren't patching a freed init section */
> -	if (init_mem_is_free && init_section_contains(addr, 4)) {
> +	if (*PTRRELOC(&init_mem_is_free) && init_section_contains(addr, 4)) {
>   		pr_debug("Skipping init section patching addr: 0x%px\n", addr);
>   		return 0;
>   	}
> 

Re: [PATCH stable 4.9] powerpc/lib: fix book3s/32 boot failure due to code patching

[Greg KH]

On Wed, May 15, 2019 at 06:40:47AM +0000, Christophe Leroy wrote:
> [Backport of upstream commit b45ba4a51cde29b2939365ef0c07ad34c8321789]
> 
> On powerpc32, patch_instruction() is called by apply_feature_fixups()
> which is called from early_init()
> 
> There is the following note in front of early_init():
>  * Note that the kernel may be running at an address which is different
>  * from the address that it was linked at, so we must use RELOC/PTRRELOC
>  * to access static data (including strings).  -- paulus
> 
> Therefore init_mem_is_free must be accessed with PTRRELOC()
> 
> Fixes: 1c38a84d4586 ("powerpc: Avoid code patching freed init sections")
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=203597
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> 
> ---
> Can't apply the upstream commit as such due to several other unrelated stuff
> like for instance STRICT_KERNEL_RWX which are missing.
> So instead, using same approach as for commit 252eb55816a6f69ef9464cad303cdb3326cdc61d

Now queued up, thanks.

greg k-h

Re: [PATCH stable 4.9] powerpc/lib: fix book3s/32 boot failure due to code patching

[Christophe Leroy]

Le 15/05/2019 à 10:29, Greg KH a écrit :
> On Wed, May 15, 2019 at 06:40:47AM +0000, Christophe Leroy wrote:
>> [Backport of upstream commit b45ba4a51cde29b2939365ef0c07ad34c8321789]
>>
>> On powerpc32, patch_instruction() is called by apply_feature_fixups()
>> which is called from early_init()
>>
>> There is the following note in front of early_init():
>>   * Note that the kernel may be running at an address which is different
>>   * from the address that it was linked at, so we must use RELOC/PTRRELOC
>>   * to access static data (including strings).  -- paulus
>>
>> Therefore init_mem_is_free must be accessed with PTRRELOC()
>>
>> Fixes: 1c38a84d4586 ("powerpc: Avoid code patching freed init sections")
>> Link: https://bugzilla.kernel.org/show_bug.cgi?id=203597
>> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
>>
>> ---
>> Can't apply the upstream commit as such due to several other unrelated stuff
>> like for instance STRICT_KERNEL_RWX which are missing.
>> So instead, using same approach as for commit 252eb55816a6f69ef9464cad303cdb3326cdc61d
> 
> Now queued up, thanks.
> 

Should go to 4.4 as well since the commit it fixes is now queued for 4.4 
([PATCH 4.4 056/266] powerpc: Avoid code patching freed init sections)

Christophe

Re: [PATCH stable 4.9] powerpc/lib: fix book3s/32 boot failure due to code patching

[Greg KH]

On Wed, May 15, 2019 at 02:35:36PM +0200, Christophe Leroy wrote:
> 
> 
> Le 15/05/2019 à 10:29, Greg KH a écrit :
> > On Wed, May 15, 2019 at 06:40:47AM +0000, Christophe Leroy wrote:
> > > [Backport of upstream commit b45ba4a51cde29b2939365ef0c07ad34c8321789]
> > > 
> > > On powerpc32, patch_instruction() is called by apply_feature_fixups()
> > > which is called from early_init()
> > > 
> > > There is the following note in front of early_init():
> > >   * Note that the kernel may be running at an address which is different
> > >   * from the address that it was linked at, so we must use RELOC/PTRRELOC
> > >   * to access static data (including strings).  -- paulus
> > > 
> > > Therefore init_mem_is_free must be accessed with PTRRELOC()
> > > 
> > > Fixes: 1c38a84d4586 ("powerpc: Avoid code patching freed init sections")
> > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=203597
> > > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> > > 
> > > ---
> > > Can't apply the upstream commit as such due to several other unrelated stuff
> > > like for instance STRICT_KERNEL_RWX which are missing.
> > > So instead, using same approach as for commit 252eb55816a6f69ef9464cad303cdb3326cdc61d
> > 
> > Now queued up, thanks.
> > 
> 
> Should go to 4.4 as well since the commit it fixes is now queued for 4.4
> ([PATCH 4.4 056/266] powerpc: Avoid code patching freed init sections)

Ok, can someone send me a backport that actually applies there?

thanks,

greg k-h

Re: [PATCH stable 4.9] powerpc/lib: fix book3s/32 boot failure due to code patching

[Christophe Leroy]

Le 15/05/2019 à 15:08, Greg KH a écrit :
> On Wed, May 15, 2019 at 02:35:36PM +0200, Christophe Leroy wrote:
>>
>>
>> Le 15/05/2019 à 10:29, Greg KH a écrit :
>>> On Wed, May 15, 2019 at 06:40:47AM +0000, Christophe Leroy wrote:
>>>> [Backport of upstream commit b45ba4a51cde29b2939365ef0c07ad34c8321789]
>>>>
>>>> On powerpc32, patch_instruction() is called by apply_feature_fixups()
>>>> which is called from early_init()
>>>>
>>>> There is the following note in front of early_init():
>>>>    * Note that the kernel may be running at an address which is different
>>>>    * from the address that it was linked at, so we must use RELOC/PTRRELOC
>>>>    * to access static data (including strings).  -- paulus
>>>>
>>>> Therefore init_mem_is_free must be accessed with PTRRELOC()
>>>>
>>>> Fixes: 1c38a84d4586 ("powerpc: Avoid code patching freed init sections")
>>>> Link: https://bugzilla.kernel.org/show_bug.cgi?id=203597
>>>> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
>>>>
>>>> ---
>>>> Can't apply the upstream commit as such due to several other unrelated stuff
>>>> like for instance STRICT_KERNEL_RWX which are missing.
>>>> So instead, using same approach as for commit 252eb55816a6f69ef9464cad303cdb3326cdc61d
>>>
>>> Now queued up, thanks.
>>>
>>
>> Should go to 4.4 as well since the commit it fixes is now queued for 4.4
>> ([PATCH 4.4 056/266] powerpc: Avoid code patching freed init sections)
> 
> Ok, can someone send me a backport that actually applies there?
> 

Done

Christophe