* Carlos Llamas cmllamas@google.com [231102 16:09]:
...
diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c index e3db8297095a..c4d60d81221b 100644 --- a/drivers/android/binder_alloc.c +++ b/drivers/android/binder_alloc.c @@ -1005,7 +1005,9 @@ enum lru_status binder_alloc_free_page(struct list_head *item, goto err_mmget; if (!mmap_read_trylock(mm)) goto err_mmap_read_lock_failed;
- vma = binder_alloc_get_vma(alloc);
- vma = vma_lookup(mm, page_addr);
- if (vma && vma != binder_alloc_get_vma(alloc))
goto err_invalid_vma;Doesn't this need to be: if (!vma || vma != binder_alloc_get_vma(alloc))
This way, we catch a different vma and a NULL vma.
Or even, just: if (vma != binder_alloc_get_vma(alloc))
if the alloc vma cannot be NULL?
If the vma_lookup() is NULL then we still need to isolate and free the given binder page and we obviously skip the zap() in this case.
I would have thought if there was no VMA, then the entire process could be avoided. Thanks for clarifying.
However, if we receive a random unexpected vma because of a corrupted address or similar, then the whole process is skipped.
Thus, why we use the check above.
-- Carlos Llamas