| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 31/83] splice: reinstate SIGPIPE/EPIPE handling | Date | Wed, 4 Jan 2017 21:06:23 +0100 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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From: Linus Torvalds <torvalds@linux-foundation.org>
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 <schwab@linux-m68k.org> Debugged-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- 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,
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