This is a note to let you know that I've just added the patch titled sunrpc/cache: drop reference when sunrpc_cache_pipe_upcall() detects a race to the 4.5-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: sunrpc-cache-drop-reference-when-sunrpc_cache_pipe_upcall-detects-a-race.patch and it can be found in the queue-4.5 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From a6ab1e8126d205238defbb55d23661a3a5c6a0d8 Mon Sep 17 00:00:00 2001 From: NeilBrown <neilb@xxxxxxxx> Date: Fri, 4 Mar 2016 17:20:13 +1100 Subject: sunrpc/cache: drop reference when sunrpc_cache_pipe_upcall() detects a race From: NeilBrown <neilb@xxxxxxxx> 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@xxxxxxxx> Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/sunrpc/cache.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/net/sunrpc/cache.c +++ b/net/sunrpc/cache.c @@ -1182,14 +1182,14 @@ int sunrpc_cache_pipe_upcall(struct cach } 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); Patches currently in stable-queue which might be from neilb@xxxxxxxx are queue-4.5/sunrpc-cache-drop-reference-when-sunrpc_cache_pipe_upcall-detects-a-race.patch -- 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