splice: reinstate SIGPIPE/EPIPE handling

Commit 8924feff66 ("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: 8924feff66 ("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>
Cc: stable@kernel.org   # v4.9
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds 2016-12-21 10:59:34 -08:00
parent 0c961c5511
commit 52bce91165

View File

@ -1087,7 +1087,13 @@ 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))
@ -1096,7 +1102,6 @@ static int wait_for_space(struct pipe_inode_info *pipe, unsigned flags)
pipe_wait(pipe);
pipe->waiting_writers--;
}
return 0;
}
static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,