Subject: Re: [PATCH v8 1/5] kasan: support backing vmalloc space with real shadow memory

From: Daniel Axtens <[email-masked]>
Date: Wed, 02 Oct 2019 11:23:06 +1000

Hi,

>>  	/*
>>  	 * Find a place in the tree where VA potentially will be
>>  	 * inserted, unless it is merged with its sibling/siblings.
>> @@ -741,6 +752,10 @@ merge_or_add_vmap_area(struct vmap_area *va,
>>  		if (sibling->va_end == va->va_start) {
>>  			sibling->va_end = va->va_end;
>>  
>> +			kasan_release_vmalloc(orig_start, orig_end,
>> +					      sibling->va_start,
>> +					      sibling->va_end);
>> +
> The same.

The call to kasan_release_vmalloc() is a static inline no-op if
CONFIG_KASAN_VMALLOC is not defined, which I thought was the preferred
way to do things rather than sprinkling the code with ifdefs?

The complier should be smart enough to eliminate all the
orig_state/orig_end stuff at compile time because it can see that it's
not used, so there's no cost in the binary.

Regards,
Daniel