From 8df441294dd34fb0b16b45f550f55e96db6af4dc Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 7 Oct 2019 16:30:51 +0100 Subject: [PATCH] pipe: Check for ring full inside of the spinlock in pipe_write() Make pipe_write() check to see if the ring has become full between it taking the pipe mutex, checking the ring status and then taking the spinlock. This can happen if a notification is written into the pipe as that happens without the pipe mutex. Signed-off-by: David Howells --- fs/pipe.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/pipe.c b/fs/pipe.c index d7b8d3f..aba2455 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -463,6 +463,11 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from) spin_lock_irq(&pipe->wait.lock); head = pipe->head; + if (pipe_full(head, pipe->tail, max_usage)) { + spin_unlock_irq(&pipe->wait.lock); + continue; + } + pipe->head = head + 1; /* Always wake up, even if the copy fails. Otherwise -- 2.7.4