From b667b867344301e24f21d4a4c844675ff61d89e1 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 24 Sep 2019 16:09:04 +0100 Subject: pipe: Advance tail pointer inside of wait spinlock in pipe_read() Advance the pipe ring tail pointer inside of wait spinlock in pipe_read() so that the pipe can be written into with kernel notifications from contexts where pipe->mutex cannot be taken. Signed-off-by: David Howells --- fs/pipe.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'fs/pipe.c') diff --git a/fs/pipe.c b/fs/pipe.c index 69afeab8a73a..ea134f69a292 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -325,9 +325,14 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to) if (!buf->len) { pipe_buf_release(pipe, buf); + spin_lock_irq(&pipe->wait.lock); tail++; pipe->tail = tail; - do_wakeup = 1; + do_wakeup = 0; + wake_up_interruptible_sync_poll_locked( + &pipe->wait, EPOLLOUT | EPOLLWRNORM); + spin_unlock_irq(&pipe->wait.lock); + kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); } total_len -= chars; if (!total_len) @@ -359,6 +364,7 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to) if (do_wakeup) { wake_up_interruptible_sync_poll(&pipe->wait, EPOLLOUT | EPOLLWRNORM); kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); + do_wakeup = 0; } pipe_wait(pipe); } -- cgit v1.2.3