From: NeilBrown <neilb@xxxxxxxx> This patch has been added to the 4.1 stable tree. If you have any objections, please let us know. =============== [ Upstream commit a6ab1e8126d205238defbb55d23661a3a5c6a0d8 ] 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@xxxxxxxx> Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx> Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx> --- 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 8d79e70..9ec709b 100644 --- a/net/sunrpc/cache.c +++ b/net/sunrpc/cache.c @@ -1175,14 +1175,14 @@ 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); -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html