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authorNeilBrown <neilb@suse.com>2016-03-04 17:20:13 +1100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-05-04 14:51:26 -0700
commit44a890802b635fb08cf4956ca29ef7cf7686ff6a (patch)
tree4990d7364a853f0360ad200bca540126b51aeb4b
parentbfdaced9ab7d00ffa857a23cdfb30d82986d96ee (diff)
sunrpc/cache: drop reference when sunrpc_cache_pipe_upcall() detects a race
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 <neilb@suse.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/sunrpc/cache.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 07edbcd8697e..311daab4161d 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -1187,14 +1187,14 @@ 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);