[PATCH 2/2] nfsd: fix potential UAF in nfsd4_cb_getattr_release

[Jeff Layton]

Once we drop the delegation reference, the fields embedded in it are no
longer safe to access. Do that last.

Fixes: c5967721e106 ("NFSD: handle GETATTR conflict with write delegation")
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
 fs/nfsd/nfs4state.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 19d39872be32..02d43f95146e 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3078,9 +3078,9 @@ nfsd4_cb_getattr_release(struct nfsd4_callback *cb)
 	struct nfs4_delegation *dp =
 			container_of(ncf, struct nfs4_delegation, dl_cb_fattr);
 
-	nfs4_put_stid(&dp->dl_stid);
 	clear_bit(CB_GETATTR_BUSY, &ncf->ncf_cb_flags);
 	wake_up_bit(&ncf->ncf_cb_flags, CB_GETATTR_BUSY);
+	nfs4_put_stid(&dp->dl_stid);
 }
 
 static const struct nfsd4_callback_ops nfsd4_cb_recall_any_ops = {

-- 
2.46.0