relayfs: fix infinite loop with splice()
Running kmemtraced, which uses splice() on relayfs, causes a hard lock on
x86-64 SMP. As described by Tom Zanussi:
It looks like you hit the same problem as described here:
commit 8191ecd1d14c6914c660dfa007154860a7908857
splice: fix infinite loop in generic_file_splice_read()
relay uses the same loop but it never got noticed or fixed.
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Tested-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/relay.c b/kernel/relay.c
index 32b0bef..09ac200 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -1317,12 +1317,9 @@
if (ret < 0)
break;
else if (!ret) {
- if (spliced)
- break;
- if (flags & SPLICE_F_NONBLOCK) {
+ if (flags & SPLICE_F_NONBLOCK)
ret = -EAGAIN;
- break;
- }
+ break;
}
*ppos += ret;