On 02/02/2018 08:20 PM, Matthew Wilcox wrote: > On Thu, Feb 01, 2018 at 11:22:55PM +0300, Andrey Ryabinin wrote: >>>> + vm = find_vm_area((void *)shadow_start); >>>> + if (vm) >>>> + vfree((void *)shadow_start); >>>> + } >>> >>> This looks like a complicated way to spell 'is_vmalloc_addr' ... >>> >> >> It's not. shadow_start is never vmalloc address. > > I'm confused. How can you call vfree() on something that isn't a vmalloc > address? >
​vfree() is able to free any address returned by __vmalloc_node_range(). And __vmalloc_node_range() gives you any address you ask. It doesn't have to be an address in [VMALLOC_START, VMALLOC_END] range. That's also how the module_alloc()/module_memfree() works on architectures that have designated area for modules.
