RDMA/uverbs: Check for null return of kmalloc_array

stable inclusion
from stable-v5.10.91
commit 16e5cad6eca1e506c38c39dc256298643fa1852a
bugzilla: 186187 https://gitee.com/openeuler/kernel/issues/I4SI2C

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=16e5cad6eca1e506c38c39dc256298643fa1852a

--------------------------------

commit 7694a7de upstream.

Because of the possible failure of the allocation, data might be NULL
pointer and will cause the dereference of the NULL pointer later.
Therefore, it might be better to check it and return -ENOMEM.

Fixes: 6884c6c4 ("RDMA/verbs: Store the write/write_ex uapi entry points in the uverbs_api")
Link: https://lore.kernel.org/r/20211231093315.1917667-1-jiasheng@iscas.ac.cnSigned-off-by: NJiasheng Jiang <jiasheng@iscas.ac.cn>
Reviewed-by: NLeon Romanovsky <leonro@nvidia.com>
Signed-off-by: NJason Gunthorpe <jgg@nvidia.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/infiniband/core/uverbs_uapi.c

@@ -450,6 +450,9 @@ static int uapi_finalize(struct uverbs_api *uapi)
 	uapi->num_write_ex = max_write_ex + 1;
 	data = kmalloc_array(uapi->num_write + uapi->num_write_ex,
 			     sizeof(*uapi->write_methods), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
 	for (i = 0; i != uapi->num_write + uapi->num_write_ex; i++)
 		data[i] = &uapi->notsupp_method;
 	uapi->write_methods = data;