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SubjectRe: [PATCH mm v2 30/33] kasan: implement stack ring for tag-based modes
On Tue, Jul 19, 2022 at 1:41 PM Marco Elver <elver@google.com> wrote:
>
> > + for (u64 i = pos - 1; i != pos - 1 - KASAN_STACK_RING_SIZE; i--) {
> > + if (alloc_found && free_found)
> > + break;
> > +
> > + entry = &stack_ring.entries[i % KASAN_STACK_RING_SIZE];
> > +
> > + /* Paired with smp_store_release() in save_stack_info(). */
> > + ptr = (void *)smp_load_acquire(&entry->ptr);
> > +
> > + if (kasan_reset_tag(ptr) != info->object ||
> > + get_tag(ptr) != get_tag(info->access_addr))
> > + continue;
> > +
> > + pid = READ_ONCE(entry->pid);
> > + stack = READ_ONCE(entry->stack);
> > + is_free = READ_ONCE(entry->is_free);
> > +
> > + /* Try detecting if the entry was changed while being read. */
> > + smp_mb();
> > + if (ptr != (void *)READ_ONCE(entry->ptr))
> > + continue;
>
> I thought the re-validation is no longer needed because of the rwlock
> protection?

Oh, yes, forgot to remove this. Will either do in v3 if there are more
things to fix, or will just send a small fix-up patch if the rest of
the series looks good.

> The rest looks fine now.

Thank you, Marco!

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