Re: [PATCH mfd+gpio 1/2] drivers: mfd: Add support for Moxtet bus

From: Dan Carpenter
Date: Sat Sep 01 2018 - 06:47:57 EST


Hi Marek,

Thank you for the patch! Perhaps something to improve:

url: https://github.com/0day-ci/linux/commits/Marek-Beh-n/drivers-mfd-Add-support-for-Moxtet-bus/20180831-031806
base: https://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd.git for-mfd-next

smatch warnings:
drivers/mfd/moxtet.c:267 of_register_moxtet_device() warn: passing zero to 'ERR_PTR'

# https://github.com/0day-ci/linux/commit/316bda5c94917aa3b0a67c3cf79cca211d08138d
git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout 316bda5c94917aa3b0a67c3cf79cca211d08138d
vim +/ERR_PTR +267 drivers/mfd/moxtet.c

316bda5c Marek Behún 2018-08-30 213
316bda5c Marek Behún 2018-08-30 214 static struct moxtet_device *
316bda5c Marek Behún 2018-08-30 215 of_register_moxtet_device(struct moxtet *moxtet, struct device_node *nc)
316bda5c Marek Behún 2018-08-30 216 {
316bda5c Marek Behún 2018-08-30 217 struct moxtet_device *dev;
316bda5c Marek Behún 2018-08-30 218 u32 val;
316bda5c Marek Behún 2018-08-30 219 int ret;
316bda5c Marek Behún 2018-08-30 220
316bda5c Marek Behún 2018-08-30 221 dev = moxtet_alloc_device(moxtet);
316bda5c Marek Behún 2018-08-30 222 if (!dev) {
316bda5c Marek Behún 2018-08-30 223 dev_err(moxtet->dev,
316bda5c Marek Behún 2018-08-30 224 "Moxtet device alloc error for %pOF\n", nc);
316bda5c Marek Behún 2018-08-30 225 return ERR_PTR(-ENOMEM);
316bda5c Marek Behún 2018-08-30 226 }
316bda5c Marek Behún 2018-08-30 227
316bda5c Marek Behún 2018-08-30 228 ret = of_property_read_u32(nc, "reg", &val);
316bda5c Marek Behún 2018-08-30 229 if (ret || val >= TURRIS_MOX_MAX_MODULES) {
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
No error code set. It means we return NULL. Presumably it leads to a
NULL dereference in the caller?

316bda5c Marek Behún 2018-08-30 230 dev_err(moxtet->dev, "%pOF has no valid 'reg' property (%d)\n",
316bda5c Marek Behún 2018-08-30 231 nc, ret);
316bda5c Marek Behún 2018-08-30 232 goto err_put;
316bda5c Marek Behún 2018-08-30 233 }
316bda5c Marek Behún 2018-08-30 234 dev->idx = val;
316bda5c Marek Behún 2018-08-30 235
316bda5c Marek Behún 2018-08-30 236 ret = of_property_read_u32(nc, "moxtet,id", &val);
316bda5c Marek Behún 2018-08-30 237 if (ret || val > 0xf) {
^^^^^^^^^

316bda5c Marek Behún 2018-08-30 238 dev_err(moxtet->dev,
316bda5c Marek Behún 2018-08-30 239 "%pOF has no valid 'moxtet,id' property (%d)\n", nc,
316bda5c Marek Behún 2018-08-30 240 ret);
316bda5c Marek Behún 2018-08-30 241 goto err_put;
316bda5c Marek Behún 2018-08-30 242 }
316bda5c Marek Behún 2018-08-30 243 dev->id = val;
316bda5c Marek Behún 2018-08-30 244
316bda5c Marek Behún 2018-08-30 245 if (moxtet->modules[dev->idx] != dev->id) {
316bda5c Marek Behún 2018-08-30 246 dev_err(moxtet->dev,
316bda5c Marek Behún 2018-08-30 247 "%pOF requested Moxtet device ID 0x%x, 0x%x found\n",
316bda5c Marek Behún 2018-08-30 248 nc, dev->id, moxtet->modules[dev->idx]);
316bda5c Marek Behún 2018-08-30 249 goto err_put;
^^^^^^^^^^^^

316bda5c Marek Behún 2018-08-30 250 }
316bda5c Marek Behún 2018-08-30 251
316bda5c Marek Behún 2018-08-30 252 of_node_get(nc);
316bda5c Marek Behún 2018-08-30 253 dev->dev.of_node = nc;
316bda5c Marek Behún 2018-08-30 254
316bda5c Marek Behún 2018-08-30 255 ret = moxtet_add_device(dev);
316bda5c Marek Behún 2018-08-30 256 if (ret) {
316bda5c Marek Behún 2018-08-30 257 dev_err(moxtet->dev,
316bda5c Marek Behún 2018-08-30 258 "Moxtet device register error for %pOF\n", nc);
316bda5c Marek Behún 2018-08-30 259 of_node_put(nc);
316bda5c Marek Behún 2018-08-30 260 goto err_put;
316bda5c Marek Behún 2018-08-30 261 }
316bda5c Marek Behún 2018-08-30 262
316bda5c Marek Behún 2018-08-30 263 return dev;
316bda5c Marek Behún 2018-08-30 264
316bda5c Marek Behún 2018-08-30 265 err_put:
316bda5c Marek Behún 2018-08-30 266 put_device(&dev->dev);
316bda5c Marek Behún 2018-08-30 @267 return ERR_PTR(ret);
316bda5c Marek Behún 2018-08-30 268 }
316bda5c Marek Behún 2018-08-30 269

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