svcrpc: take lock on turning entry NEGATIVE in cache_check
authorJ. Bruce Fields <bfields@redhat.com>
Mon, 3 Jan 2011 20:10:27 +0000 (15:10 -0500)
committerJ. Bruce Fields <bfields@redhat.com>
Tue, 4 Jan 2011 21:49:24 +0000 (16:49 -0500)
commit6bab93f87ec703bf6650875881b11f9f27d7da56
tree1042182b79c43747404fe91b03b3b958246c3a9c
parentda165dd60e136d0609e0a2c0c2a9b9a5372200d6
svcrpc: take lock on turning entry NEGATIVE in cache_check

We attempt to turn a cache entry negative in place.  But that entry may
already have been filled in by some other task since we last checked
whether it was valid, so we could be modifying an already-valid entry.
If nothing else there's a likely leak in such a case when the entry is
eventually put() and contents are not freed because it has
CACHE_NEGATIVE set.

So, take the cache_lock just as sunrpc_cache_update() does.

Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
net/sunrpc/cache.c