[PATCH] relayfs: fix infinite loop with splice()

From: Pekka J Enberg
Date: Fri Oct 24 2008 - 03:48:35 EST

From: Tom Zanussi <zanussi@xxxxxxxxxxx>

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@xxxxxxxxxx>
Tested-by: Pekka Enberg <penberg@xxxxxxxxxxxxxx>
Signed-off-by: Tom Zanussi <tzanussi@xxxxxxxxx>
Signed-off-by: Pekka Enberg <penberg@xxxxxxxxxxxxxx>
kernel/relay.c | 7 ++-----
1 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/kernel/relay.c b/kernel/relay.c
index 8d13a78..6a4d439 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -1318,12 +1318,9 @@ static ssize_t relay_file_splice_read(struct file *in,
if (ret < 0)
else if (!ret) {
- if (spliced)
- break;
- if (flags & SPLICE_F_NONBLOCK) {
+ if (flags & SPLICE_F_NONBLOCK)
ret = -EAGAIN;
- break;
- }
+ break;

*ppos += ret;

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