UPSTREAM: io_uring: fix double poll leak on repolling
commit c0737fa9a5a5cf5a053bcc983f72d58919b997c6 upstream.
We have re-polling for partial IO, so a request can be polled twice. If
it used two poll entries the first time then on the second
io_arm_poll_handler() it will find the old apoll entry and NULL
kmalloc()'ed second entry, i.e. apoll->double_poll, so leaking it.
Fixes: 10c873334feba ("io_uring: allow re-poll if we made progress")
Change-Id: If720ddcd7e488c0c336533d8dde00864689648ca
Signed-off-by: Pavel Begunkov <[email protected]>
Link: https://lore.kernel.org/r/fee2452494222ecc7f1f88c8fb659baef971414a.1655852245.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Bug: 268174392
(cherry picked from commit c1a279d79e313bd9b0ed31025edc68394bfc40ab)
Signed-off-by: Greg Kroah-Hartman <[email protected]>
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 0eed453..9ef7235 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -5761,10 +5761,12 @@ static int io_arm_poll_handler(struct io_kiocb *req)
mask |= POLLOUT | POLLWRNORM;
}
- if (req->flags & REQ_F_POLLED)
+ if (req->flags & REQ_F_POLLED) {
apoll = req->apoll;
- else
+ kfree(apoll->double_poll);
+ } else {
apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
+ }
if (unlikely(!apoll))
return IO_APOLL_ABORTED;
apoll->double_poll = NULL;
