This is a note to let you know that I've just added the patch titled nfsd: call cache_put if xdr_reserve_space returns NULL to the 5.15-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: nfsd-call-cache_put-if-xdr_reserve_space-returns-nul.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 667cf2f7bf98d4161bdc4cf9087cc79226f8e3e3 Author: Guoqing Jiang <guoqing.jiang@xxxxxxxxx> Date: Wed Aug 21 22:03:18 2024 +0800 nfsd: call cache_put if xdr_reserve_space returns NULL [ Upstream commit d078cbf5c38de83bc31f83c47dcd2184c04a50c7 ] If not enough buffer space available, but idmap_lookup has triggered lookup_fn which calls cache_get and returns successfully. Then we missed to call cache_put here which pairs with cache_get. Fixes: ddd1ea563672 ("nfsd4: use xdr_reserve_space in attribute encoding") Signed-off-by: Guoqing Jiang <guoqing.jiang@xxxxxxxxx> Reviwed-by: Jeff Layton <jlayton@xxxxxxxxxx> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/nfsd/nfs4idmap.c b/fs/nfsd/nfs4idmap.c index 5e9809aff37eb..717e400b16b86 100644 --- a/fs/nfsd/nfs4idmap.c +++ b/fs/nfsd/nfs4idmap.c @@ -581,6 +581,7 @@ static __be32 idmap_id_to_name(struct xdr_stream *xdr, .id = id, .type = type, }; + __be32 status = nfs_ok; __be32 *p; int ret; struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id); @@ -593,12 +594,16 @@ static __be32 idmap_id_to_name(struct xdr_stream *xdr, return nfserrno(ret); ret = strlen(item->name); WARN_ON_ONCE(ret > IDMAP_NAMESZ); + p = xdr_reserve_space(xdr, ret + 4); - if (!p) - return nfserr_resource; - p = xdr_encode_opaque(p, item->name, ret); + if (unlikely(!p)) { + status = nfserr_resource; + goto out_put; + } + xdr_encode_opaque(p, item->name, ret); +out_put: cache_put(&item->h, nn->idtoname_cache); - return 0; + return status; } static bool