From c0737fa9a5a5cf5a053bcc983f72d58919b997c6 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Wed, 22 Jun 2022 00:00:37 +0100 Subject: io_uring: fix double poll leak on repolling 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") Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/fee2452494222ecc7f1f88c8fb659baef971414a.1655852245.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- fs/io_uring.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index cb719a53b8bd..5c95755619e2 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -7208,6 +7208,7 @@ static int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags) mask |= EPOLLEXCLUSIVE; if (req->flags & REQ_F_POLLED) { apoll = req->apoll; + kfree(apoll->double_poll); } else if (!(issue_flags & IO_URING_F_UNLOCKED) && !list_empty(&ctx->apoll_cache)) { apoll = list_first_entry(&ctx->apoll_cache, struct async_poll, -- cgit