Commit 8df44129 authored Oct 07, 2019 by David Howells

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 <dhowells@redhat.com>

parent 7e25a73f

fs/pipe.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -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

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