On 10/17/24 1:53 AM, David Hildenbrand wrote:
On 17.10.24 10:51, David Hildenbrand wrote:
On 16.10.24 22:22, John Hubbard wrote:
...
And staring at memfd_pin_folios(), don't we have the same issue there if
check_and_migrate_movable_folios() fails?
Yes, it looks very clearly like the exact same bug, in a different location.
This complicated return code is the gift that keeps on giving. Although
likely people are just copying the pattern, which had the problem.
diff --git a/mm/gup.c b/mm/gup.c
index a82890b46a36..f79974d38608 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -3708,12 +3708,10 @@ long memfd_pin_folios(struct file *memfd, loff_t
start, loff_t end,
ret = check_and_migrate_movable_folios(nr_folios, folios);
} while (ret == -EAGAIN);
- memalloc_pin_restore(flags);
- return ret ? ret : nr_folios;
err:
memalloc_pin_restore(flags);
- unpin_folios(folios, nr_folios);
-
- return ret;
+ if (ret)
+ unpin_folios(folios, nr_folios);
+ return ret ? ret : nr_folios;
That looks correct. I can send this out with the other patch as a tiny
2-patch series since they are related. Would you prefer to appear
as a Signed-off-by, or a Suggested-by, or "other"? :)
}
EXPORT_SYMBOL_GPL(memfd_pin_folios);
thanks,
--
John Hubbard
