linux-kernel - [PATCH 5.15 166/171] aio: Fix incorrect usage of eventfd_signal

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Date:   Mon, 13 Dec 2021 10:31:21 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Xie Yongji <xieyongji@...edance.com>,
        Eric Biggers <ebiggers@...gle.com>
Subject: [PATCH 5.15 166/171] aio: Fix incorrect usage of eventfd_signal_allowed()

From: Xie Yongji <xieyongji@...edance.com>

commit 4b3749865374899e115aa8c48681709b086fe6d3 upstream.

We should defer eventfd_signal() to the workqueue when
eventfd_signal_allowed() return false rather than return
true.

Fixes: b542e383d8c0 ("eventfd: Make signal recursion protection a task bit")
Signed-off-by: Xie Yongji <xieyongji@...edance.com>
Link: https://lore.kernel.org/r/20210913111928.98-1-xieyongji@bytedance.com
Reviewed-by: Eric Biggers <ebiggers@...gle.com>
Signed-off-by: Eric Biggers <ebiggers@...gle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/aio.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1761,7 +1761,7 @@ static int aio_poll_wake(struct wait_que
 		list_del_init(&req->wait.entry);
 		list_del(&iocb->ki_list);
 		iocb->ki_res.res = mangle_poll(mask);
-		if (iocb->ki_eventfd && eventfd_signal_allowed()) {
+		if (iocb->ki_eventfd && !eventfd_signal_allowed()) {
 			iocb = NULL;
 			INIT_WORK(&req->work, aio_poll_put_work);
 			schedule_work(&req->work);