From: NeilBrown <ne...@suse.com>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
commit a6ab1e8126d205238defbb55d23661a3a5c6a0d8 upstream.
sunrpc_cache_pipe_upcall() can detect a race if CACHE_PENDING is no longer
set. In this case it aborts the queuing of the upcall.
However it has already taken a new counted reference on "h" and
doesn't "put" it, even though it frees the data structure holding the reference.
So let's delay the "cache_get" until we know we need it.
Fixes: f9e1aedc6c79 ("sunrpc/cache: remove races with queuing an upcall.")
Signed-off-by: NeilBrown <ne...@suse.com>
Signed-off-by: J. Bruce Fields <bfie...@redhat.com>
Signed-off-by: Jiri Slaby <jsl...@suse.cz>
---
net/sunrpc/cache.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index f3e2b7d8f325..b81e0a33a8be 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -1189,14 +1189,14 @@ int sunrpc_cache_pipe_upcall(struct cache_detail
*detail, struct cache_head *h)
}
crq->q.reader = 0;
- crq->item = cache_get(h);
crq->buf = buf;
crq->len = 0;
crq->readers = 0;
spin_lock(&queue_lock);
- if (test_bit(CACHE_PENDING, &h->flags))
+ if (test_bit(CACHE_PENDING, &h->flags)) {
+ crq->item = cache_get(h);
list_add_tail(&crq->q.list, &detail->queue);
- else
+ } else
/* Lost a race, no longer PENDING, so don't enqueue */
ret = -EAGAIN;
spin_unlock(&queue_lock);
--
2.8.2
