[PATCH V5] nfsd: fix nfsd4_create_reclaim_record_grace crp null-ptr-deref in nfs4recover

[Lai Zewei]

nfs4_client_to_reclaim() may return NULL if alloc_reclaim() fails. 
The caller __nfsd4_create_reclaim_record_grace() then unconditionally
dereferences the returned pointer via crp->cr_clp = clp, leading to a
null-ptr-deref crash.

Add a NULL check before assignment. If crp is NULL, just return.

Fixes: 4552f4e3f2c9 ("nfsd: change nfs4_client_to_reclaim() to allocate data")
Signed-off-by: Lai Zewei <laizewei3@xxxxxxxxxx>
---
 fs/nfsd/nfs4recover.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index 6ea25a52d2f4..005e3990da99 100644
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -116,7 +116,8 @@ __nfsd4_create_reclaim_record_grace(struct nfs4_client *clp,
 	struct nfs4_client_reclaim *crp;
 
 	crp = nfs4_client_to_reclaim(name, princhash, nn);
-	crp->cr_clp = clp;
+	if (crp)
+		crp->cr_clp = clp;
 }
 
 static void
-- 
2.52.0