def lookup_cache_by_address(obj: drgn.Object) -> Optional[drgn.Object]:
pfn = virt_to_pfn(sdb.get_prog(), obj)
page = pfn_to_page(pfn)
cache = page.slab_cache
try:
# read the name to force FaultError if any
_ = cache.name.string_().decode('utf-8')
except drgn.FaultError:
return None
return cache
def test_virt_to_from_pfn(self):
with self._pages() as (map, _, pfns):
for i, pfn in enumerate(pfns):
virt = pfn_to_virt(self.prog, pfn)
# Test that we got the correct virtual address by reading from
# it and comparing it to the mmap.
self.assertEqual(
self.prog.read(virt, mmap.PAGESIZE),
map[i * mmap.PAGESIZE : (i + 1) * mmap.PAGESIZE],
)
# Test the opposite direction.
self.assertEqual(virt_to_pfn(virt), pfn)