Re: [PATCH v3 4/4] leds: pca955x: Add HW blink support
From: Dan Carpenter
Date: Tue Apr 12 2022 - 08:28:44 EST
Hi Eddie,
url: https://github.com/intel-lab-lkp/linux/commits/Eddie-James/leds-pca955x-Add-HW-blink-support/20220412-002330
base: git://git.kernel.org/pub/scm/linux/kernel/git/pavel/linux-leds.git for-next
config: i386-randconfig-m021-20220411 (https://download.01.org/0day-ci/archive/20220412/202204121953.zHZcX6EV-lkp@xxxxxxxxx/config)
compiler: gcc-11 (Debian 11.2.0-19) 11.2.0
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
smatch warnings:
drivers/leds/leds-pca955x.c:455 pca955x_led_blink() error: uninitialized symbol 'ret'.
vim +/ret +455 drivers/leds/leds-pca955x.c
3b7b1899f6cc6d Eddie James 2022-04-11 390 static int pca955x_led_blink(struct led_classdev *led_cdev,
3b7b1899f6cc6d Eddie James 2022-04-11 391 unsigned long *delay_on, unsigned long *delay_off)
3b7b1899f6cc6d Eddie James 2022-04-11 392 {
3b7b1899f6cc6d Eddie James 2022-04-11 393 struct pca955x_led *pca955x_led = led_to_pca955x(led_cdev);
3b7b1899f6cc6d Eddie James 2022-04-11 394 struct pca955x *pca955x = pca955x_led->pca955x;
3b7b1899f6cc6d Eddie James 2022-04-11 395 unsigned long p = *delay_on + *delay_off;
3b7b1899f6cc6d Eddie James 2022-04-11 396 int ret;
3b7b1899f6cc6d Eddie James 2022-04-11 397
3b7b1899f6cc6d Eddie James 2022-04-11 398 mutex_lock(&pca955x->lock);
3b7b1899f6cc6d Eddie James 2022-04-11 399
3b7b1899f6cc6d Eddie James 2022-04-11 400 if (p) {
3b7b1899f6cc6d Eddie James 2022-04-11 401 if (*delay_on != *delay_off) {
3b7b1899f6cc6d Eddie James 2022-04-11 402 ret = -EINVAL;
3b7b1899f6cc6d Eddie James 2022-04-11 403 goto out;
3b7b1899f6cc6d Eddie James 2022-04-11 404 }
3b7b1899f6cc6d Eddie James 2022-04-11 405
3b7b1899f6cc6d Eddie James 2022-04-11 406 if (p < pca955x_psc_to_period(pca955x, 0) ||
3b7b1899f6cc6d Eddie James 2022-04-11 407 p > pca955x_psc_to_period(pca955x, 0xff)) {
3b7b1899f6cc6d Eddie James 2022-04-11 408 ret = -EINVAL;
3b7b1899f6cc6d Eddie James 2022-04-11 409 goto out;
3b7b1899f6cc6d Eddie James 2022-04-11 410 }
3b7b1899f6cc6d Eddie James 2022-04-11 411 } else {
3b7b1899f6cc6d Eddie James 2022-04-11 412 p = pca955x->active_blink ? pca955x->blink_period :
3b7b1899f6cc6d Eddie James 2022-04-11 413 PCA955X_BLINK_DEFAULT_MS;
3b7b1899f6cc6d Eddie James 2022-04-11 414 }
3b7b1899f6cc6d Eddie James 2022-04-11 415
3b7b1899f6cc6d Eddie James 2022-04-11 416 if (!pca955x->active_blink ||
3b7b1899f6cc6d Eddie James 2022-04-11 417 pca955x->active_blink == BIT(pca955x_led->led_num) ||
3b7b1899f6cc6d Eddie James 2022-04-11 418 pca955x->blink_period == p) {
3b7b1899f6cc6d Eddie James 2022-04-11 419 u8 psc = pca955x_period_to_psc(pca955x, p);
f46e9203d9a100 Nate Case 2008-07-16 420
3b7b1899f6cc6d Eddie James 2022-04-11 421 if (!test_and_set_bit(pca955x_led->led_num,
3b7b1899f6cc6d Eddie James 2022-04-11 422 &pca955x->active_blink)) {
3b7b1899f6cc6d Eddie James 2022-04-11 423 u8 ls;
3b7b1899f6cc6d Eddie James 2022-04-11 424 int reg = pca955x_led->led_num / 4;
3b7b1899f6cc6d Eddie James 2022-04-11 425 int bit = pca955x_led->led_num % 4;
3b7b1899f6cc6d Eddie James 2022-04-11 426
3b7b1899f6cc6d Eddie James 2022-04-11 427 ret = pca955x_read_ls(pca955x, reg, &ls);
3b7b1899f6cc6d Eddie James 2022-04-11 428 if (ret)
3b7b1899f6cc6d Eddie James 2022-04-11 429 goto out;
3b7b1899f6cc6d Eddie James 2022-04-11 430
3b7b1899f6cc6d Eddie James 2022-04-11 431 ls = pca955x_ledsel(ls, bit, PCA955X_LS_BLINK0);
9e58c2a7bb91f6 Eddie James 2022-04-11 432 ret = pca955x_write_ls(pca955x, reg, ls);
3b7b1899f6cc6d Eddie James 2022-04-11 433 if (ret)
3b7b1899f6cc6d Eddie James 2022-04-11 434 goto out;
3b7b1899f6cc6d Eddie James 2022-04-11 435 }
3b7b1899f6cc6d Eddie James 2022-04-11 436
3b7b1899f6cc6d Eddie James 2022-04-11 437 if (pca955x->blink_period != p) {
3b7b1899f6cc6d Eddie James 2022-04-11 438 pca955x->blink_period = p;
3b7b1899f6cc6d Eddie James 2022-04-11 439 ret = pca955x_write_psc(pca955x, 0, psc);
3b7b1899f6cc6d Eddie James 2022-04-11 440 if (ret)
3b7b1899f6cc6d Eddie James 2022-04-11 441 goto out;
3b7b1899f6cc6d Eddie James 2022-04-11 442 }
Can both the !test_and_set_bit() and pca955x->blink_period != p conditions
be false? If so then "ret" is uninitialized.
3b7b1899f6cc6d Eddie James 2022-04-11 443
3b7b1899f6cc6d Eddie James 2022-04-11 444 p = pca955x_psc_to_period(pca955x, psc);
3b7b1899f6cc6d Eddie James 2022-04-11 445 p /= 2;
3b7b1899f6cc6d Eddie James 2022-04-11 446 *delay_on = p;
3b7b1899f6cc6d Eddie James 2022-04-11 447 *delay_off = p;
3b7b1899f6cc6d Eddie James 2022-04-11 448 } else {
3b7b1899f6cc6d Eddie James 2022-04-11 449 ret = -EBUSY;
3b7b1899f6cc6d Eddie James 2022-04-11 450 }
e7e11d8ba807d4 Alexander Stein 2012-05-29 451
1591caf2d5eafd Cédric Le Goater 2017-08-30 452 out:
e7e11d8ba807d4 Alexander Stein 2012-05-29 453 mutex_unlock(&pca955x->lock);
f46e9203d9a100 Nate Case 2008-07-16 454
1591caf2d5eafd Cédric Le Goater 2017-08-30 @455 return ret;
f46e9203d9a100 Nate Case 2008-07-16 456 }
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