[PATCH 4.19 85/91] NFSv4: Fix an Oops in nfs4_do_setattr

[Greg Kroah-Hartman]

From: Trond Myklebust <trond.mykleb...@hammerspace.com>

commit 09a54f0ebfe263bc27c90bbd80187b9a93283887 upstream.

If the user specifies an open mode of 3, then we don't have a NFSv4 state
attached to the context, and so we Oops when we try to dereference it.

Reported-by: Olga Kornievskaia <a...@umich.edu>
Fixes: 29b59f9416937 ("NFSv4: change nfs4_do_setattr to take...")
Signed-off-by: Trond Myklebust <trond.mykleb...@hammerspace.com>
Cc: sta...@vger.kernel.org # v4.10: 991eedb1371dc: NFSv4: Only pass the...
Cc: sta...@vger.kernel.org # v4.10+
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 fs/nfs/nfs4proc.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -3133,7 +3133,7 @@ static int _nfs4_do_setattr(struct inode
 
        if (nfs4_copy_delegation_stateid(inode, FMODE_WRITE, &arg->stateid, 
&delegation_cred)) {
                /* Use that stateid */
-       } else if (ctx != NULL) {
+       } else if (ctx != NULL && ctx->state) {
                struct nfs_lock_context *l_ctx;
                if (!nfs4_valid_open_stateid(ctx->state))
                        return -EBADF;