Commit 8df44129 authored by David Howells's avatar 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: default avatarDavid Howells <dhowells@redhat.com>
parent 7e25a73f
...@@ -463,6 +463,11 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from) ...@@ -463,6 +463,11 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
spin_lock_irq(&pipe->wait.lock); spin_lock_irq(&pipe->wait.lock);
head = pipe->head; head = pipe->head;
if (pipe_full(head, pipe->tail, max_usage)) {
spin_unlock_irq(&pipe->wait.lock);
continue;
}
pipe->head = head + 1; pipe->head = head + 1;
/* Always wake up, even if the copy fails. Otherwise /* Always wake up, even if the copy fails. Otherwise
......
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