From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:60070 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758471AbdADULY (ORCPT ); Wed, 4 Jan 2017 15:11:24 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Linus Torvalds Subject: [PATCH 4.9 31/83] splice: reinstate SIGPIPE/EPIPE handling Date: Wed, 4 Jan 2017 21:06:23 +0100 Message-Id: <20170104200447.837012413@linuxfoundation.org> In-Reply-To: <20170104200446.541604386@linuxfoundation.org> References: <20170104200446.541604386@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Linus Torvalds commit 52bce91165e5f2db422b2b972e83d389e5e4725c upstream. Commit 8924feff66f3 ("splice: lift pipe_lock out of splice_to_pipe()") caused a regression when there were no more readers left on a pipe that was being spliced into: rather than the expected SIGPIPE and -EPIPE return value, the writer would end up waiting forever for space to free up (which obviously was not going to happen with no readers around). Fixes: 8924feff66f3 ("splice: lift pipe_lock out of splice_to_pipe()") Reported-and-tested-by: Andreas Schwab Debugged-by: Al Viro Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/splice.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/fs/splice.c +++ b/fs/splice.c @@ -1086,7 +1086,13 @@ EXPORT_SYMBOL(do_splice_direct); static int wait_for_space(struct pipe_inode_info *pipe, unsigned flags) { - while (pipe->nrbufs == pipe->buffers) { + for (;;) { + if (unlikely(!pipe->readers)) { + send_sig(SIGPIPE, current, 0); + return -EPIPE; + } + if (pipe->nrbufs != pipe->buffers) + return 0; if (flags & SPLICE_F_NONBLOCK) return -EAGAIN; if (signal_pending(current)) @@ -1095,7 +1101,6 @@ static int wait_for_space(struct pipe_in pipe_wait(pipe); pipe->waiting_writers--; } - return 0; } static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,