[linux-next:master 7267/7959] drivers/firmware/arm_scmi/driver.c:1214 scmi_iterator_run() warn: variable dereferenced before check 'i' (see line 1210)

[linux-next:master 7267/7959] drivers/firmware/arm_scmi/driver.c:1214 scmi_iterator_run() warn: variable dereferenced before check 'i' (see line 1210)

[Dan Carpenter]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   5469f0c06732a077c70a759a81f2a1f00b277694
commit: 36b6ea0fc6bcbc618fe20d33a3b529a6d0653d99 [7267/7959] firmware: arm_scmi: Add iterators for multi-part commands
config: arm64-randconfig-m031-20220429 (https://download.01.org/0day-ci/archive/20220430/202204300741.1Vg3IhCp-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 11.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

smatch warnings:
drivers/firmware/arm_scmi/driver.c:1214 scmi_iterator_run() warn: variable dereferenced before check 'i' (see line 1210)

vim +/i +1214 drivers/firmware/arm_scmi/driver.c

36b6ea0fc6bcbc Cristian Marussi 2022-03-30  1205  static int scmi_iterator_run(void *iter)
36b6ea0fc6bcbc Cristian Marussi 2022-03-30  1206  {
36b6ea0fc6bcbc Cristian Marussi 2022-03-30  1207  	int ret = -EINVAL;
36b6ea0fc6bcbc Cristian Marussi 2022-03-30  1208  	struct scmi_iterator *i = iter;
36b6ea0fc6bcbc Cristian Marussi 2022-03-30  1209  	struct scmi_iterator_state *st = &i->state;
36b6ea0fc6bcbc Cristian Marussi 2022-03-30 @1210  	struct scmi_iterator_ops *iops = i->ops;
                                                                                         ^^^^^^^
Dereference

36b6ea0fc6bcbc Cristian Marussi 2022-03-30  1211  	const struct scmi_protocol_handle *ph = i->ph;
36b6ea0fc6bcbc Cristian Marussi 2022-03-30  1212  	const struct scmi_xfer_ops *xops = ph->xops;
36b6ea0fc6bcbc Cristian Marussi 2022-03-30  1213  
36b6ea0fc6bcbc Cristian Marussi 2022-03-30 @1214  	if (!i)
                                                            ^^^
Checked too late

36b6ea0fc6bcbc Cristian Marussi 2022-03-30  1215  		return ret;
36b6ea0fc6bcbc Cristian Marussi 2022-03-30  1216  
36b6ea0fc6bcbc Cristian Marussi 2022-03-30  1217  	do {
36b6ea0fc6bcbc Cristian Marussi 2022-03-30  1218  		iops->prepare_message(i->msg, st->desc_index, i->priv);
36b6ea0fc6bcbc Cristian Marussi 2022-03-30  1219  		ret = xops->do_xfer(ph, i->t);
36b6ea0fc6bcbc Cristian Marussi 2022-03-30  1220  		if (ret)
36b6ea0fc6bcbc Cristian Marussi 2022-03-30  1221  			break;
36b6ea0fc6bcbc Cristian Marussi 2022-03-30  1222  
36b6ea0fc6bcbc Cristian Marussi 2022-03-30  1223  		ret = iops->update_state(st, i->resp, i->priv);

-- 
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https://01.org/lkp