[ceph-client:testing 2/3] net/ceph/mon_client.c:928:2: warning: function 'do_mon_command_vargs' might be a candidate for 'gnu_printf' format attribute

[kernel test robot <lkp@xxxxxxxxx>]

tree:   https://github.com/ceph/ceph-client.git testing
head:   a274f50dee76e2182580cafeb908d95bda2cac70
commit: c3e9a9f0a4b9178a5c4068b73d6579e8346cd3f3 [2/3] libceph: switch to the new "osd blocklist add" command
config: arm-randconfig-r012-20200916 (attached as .config)
compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        git checkout c3e9a9f0a4b9178a5c4068b73d6579e8346cd3f3
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

   net/ceph/mon_client.c: In function 'do_mon_command_vargs':
>> net/ceph/mon_client.c:928:2: warning: function 'do_mon_command_vargs' might be a candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
     928 |  len = vsprintf(h->str, fmt, ap);
         |  ^~~

# https://github.com/ceph/ceph-client/commit/c3e9a9f0a4b9178a5c4068b73d6579e8346cd3f3
git remote add ceph-client https://github.com/ceph/ceph-client.git
git fetch --no-tags ceph-client testing
git checkout c3e9a9f0a4b9178a5c4068b73d6579e8346cd3f3
vim +928 net/ceph/mon_client.c

   898	
   899	static int do_mon_command_vargs(struct ceph_mon_client *monc,
   900					const char *fmt, va_list ap)
   901	{
   902		struct ceph_mon_generic_request *req;
   903		struct ceph_mon_command *h;
   904		int ret = -ENOMEM;
   905		int len;
   906	
   907		req = alloc_generic_request(monc, GFP_NOIO);
   908		if (!req)
   909			goto out;
   910	
   911		req->request = ceph_msg_new(CEPH_MSG_MON_COMMAND, 256, GFP_NOIO, true);
   912		if (!req->request)
   913			goto out;
   914	
   915		req->reply = ceph_msg_new(CEPH_MSG_MON_COMMAND_ACK, 512, GFP_NOIO,
   916					  true);
   917		if (!req->reply)
   918			goto out;
   919	
   920		mutex_lock(&monc->mutex);
   921		register_generic_request(req);
   922		h = req->request->front.iov_base;
   923		h->monhdr.have_version = 0;
   924		h->monhdr.session_mon = cpu_to_le16(-1);
   925		h->monhdr.session_mon_tid = 0;
   926		h->fsid = monc->monmap->fsid;
   927		h->num_strs = cpu_to_le32(1);
 > 928		len = vsprintf(h->str, fmt, ap);
   929		h->str_len = cpu_to_le32(len);
   930		send_generic_request(monc, req);
   931		mutex_unlock(&monc->mutex);
   932	
   933		ret = wait_generic_request(req);
   934	out:
   935		put_generic_request(req);
   936		return ret;
   937	}
   938	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx

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