Re: [PATCH v3] mm: Add kvfree_sensitive() for freeing sensitive data objects

[Joe Perches]

On Thu, 2020-05-14 at 05:00 -0700, Matthew Wilcox wrote:
> On Thu, May 14, 2020 at 09:00:40PM +1000, Balbir Singh wrote:
> > I wonder if the right thing to do is also to disable pre-emption, just so that the thread does not linger on with sensitive data.
> > 
> > void kvfree_sensitive(const void *addr, size_t len)
> > {
> > 	preempt_disable();
> > 	if (likely(!ZERO_OR_NULL_PTR(addr))) {
> > 		memzero_explicit((void *)addr, len);
> > 		kvfree(addr);
> > 	}
> > 	preempt_enable();
> > }
> > EXPORT_SYMBOL(kvfree_sensitive);
> 
> If it's _that_ sensitive then the caller should have disabled preemption.
> Because preemption could otherwise have occurred immediately before
> kvfree_sensitive() was called.

static inline ?