The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
Possible dependencies:
c0737fa9a5a5 ("io_uring: fix double poll leak on repolling")
10c873334feb ("io_uring: allow re-poll if we made progress")
52dd86406dfa ("io_uring: enable EPOLLEXCLUSIVE for accept poll")
4d9237e32c5d ("io_uring: recycle apoll_poll entries")
cc3cec8367cb ("io_uring: speedup provided buffer handling")
d5ec1dfaf59b ("io-uring: add __fill_cqe function")
77bc59b49817 ("io_uring: avoid ring quiesce while registering/unregistering eventfd")
0d7c1153d929 ("io_uring: Clean up a false-positive warning from GCC 9.3.0")
42a7b4ed45e7 ("Merge tag 'for-5.17/io_uring-2022-01-11' of git://git.kernel.dk/linux-block")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From c0737fa9a5a5cf5a053bcc983f72d58919b997c6 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@xxxxxxxxx>
Date: Wed, 22 Jun 2022 00:00:37 +0100
Subject: [PATCH] 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 <asml.silence@xxxxxxxxx>
Link: https://lore.kernel.org/r/fee2452494222ecc7f1f88c8fb659baef971414a.1655852245.git.asml.silence@xxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
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,
