Re: [PATCH 18/18] x86/traps: Use a new on_thread_stack() helper to clean up an assertion

Andy Lutomirski
2017-11-01T10:45:37Z

I added a commit message :)

On Wed, Nov 1, 2017 at 3:31 AM, Borislav Petkov <bp@suse.de> wrote:
> On Thu, Oct 26, 2017 at 01:26:50AM -0700, Andy Lutomirski wrote:
>> Signed-off-by: Andy Lutomirski <luto@kernel.org>
>> ---
>> arch/x86/include/asm/processor.h | 6 ++++++
>> arch/x86/kernel/traps.c | 3 +--
>> 2 files changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
>> index 562c575d8bc3..26fc33231cbd 100644
>> --- a/arch/x86/include/asm/processor.h
>> +++ b/arch/x86/include/asm/processor.h
>> @@ -541,6 +541,12 @@ static inline unsigned long current_top_of_stack(void)
>> #endif
>> }
>>
>> +static inline bool on_thread_stack(void)
>> +{
>> + return (unsigned long)(current_top_of_stack() -
>> + current_stack_pointer) < THREAD_SIZE;
>> +}
>> +
>> #ifdef CONFIG_PARAVIRT
>> #include <asm/paravirt.h>
>> #else
>> diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
>> index 67db4f43309e..42a9c4458f5d 100644
>> --- a/arch/x86/kernel/traps.c
>> +++ b/arch/x86/kernel/traps.c
>> @@ -141,8 +141,7 @@ void ist_begin_non_atomic(struct pt_regs *regs)
>> * will catch asm bugs and any attempt to use ist_preempt_enable
>> * from double_fault.
>> */
>> - BUG_ON((unsigned long)(current_top_of_stack() -
>> - current_stack_pointer) >= THREAD_SIZE);
>> + BUG_ON(!on_thread_stack());
>>
>> preempt_enable_no_resched();
>> }
>> --
>
> Having a commit message is always better. Other than that:
>
> Reviewed-by: Borislav Petkov <bp@suse.de>
>
> --
> Regards/Gruss,
> Boris.
>
> SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
> --