From: Dan Carpenter <dan.carpenter@linaro.org>
To: oe-kbuild@lists.linux.dev, Takashi Iwai <tiwai@suse.de>
Cc: lkp@intel.com, oe-kbuild-all@lists.linux.dev,
linux-kernel@vger.kernel.org,
Thomas Zimmermann <tzimmermann@suse.de>
Subject: drivers/gpu/drm/udl/udl_main.c:259 udl_get_urb_locked() warn: can 'unode' even be NULL?
Date: Tue, 2 May 2023 14:19:04 +0300 [thread overview]
Message-ID: <e35cd818-d2f7-4d5e-abf8-b3448ca224aa@kili.mountain> (raw)
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 2caeeb9d4a1bccd923b7918427f9e9ef7151ddd8
commit: c5c354a3a4728045e1342166394c615d75d45377 drm/udl: Fix inconsistent urbs.count value during udl_free_urb_list()
config: parisc-randconfig-m031-20230421 (https://download.01.org/0day-ci/archive/20230423/202304230801.ncoG1XDr-lkp@intel.com/config)
compiler: hppa-linux-gcc (GCC) 12.1.0
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Link: https://lore.kernel.org/r/202304230801.ncoG1XDr-lkp@intel.com/
smatch warnings:
drivers/gpu/drm/udl/udl_main.c:259 udl_get_urb_locked() warn: can 'unode' even be NULL?
vim +/unode +259 drivers/gpu/drm/udl/udl_main.c
c5c354a3a47280 Takashi Iwai 2022-09-08 236 static struct urb *udl_get_urb_locked(struct udl_device *udl, long timeout)
5320918b9a8786 Dave Airlie 2010-12-15 237 {
c5c354a3a47280 Takashi Iwai 2022-09-08 238 struct urb_node *unode;
5320918b9a8786 Dave Airlie 2010-12-15 239
c5c354a3a47280 Takashi Iwai 2022-09-08 240 assert_spin_locked(&udl->urbs.lock);
5320918b9a8786 Dave Airlie 2010-12-15 241
acd45c56790a3b Takashi Iwai 2022-08-04 242 /* Wait for an in-flight buffer to complete and get re-queued */
acd45c56790a3b Takashi Iwai 2022-08-04 243 if (!wait_event_lock_irq_timeout(udl->urbs.sleep,
c5c354a3a47280 Takashi Iwai 2022-09-08 244 !udl->urbs.count ||
acd45c56790a3b Takashi Iwai 2022-08-04 245 !list_empty(&udl->urbs.list),
acd45c56790a3b Takashi Iwai 2022-08-04 246 udl->urbs.lock, timeout)) {
acd45c56790a3b Takashi Iwai 2022-08-04 247 DRM_INFO("wait for urb interrupted: available: %d\n",
acd45c56790a3b Takashi Iwai 2022-08-04 248 udl->urbs.available);
c5c354a3a47280 Takashi Iwai 2022-09-08 249 return NULL;
acd45c56790a3b Takashi Iwai 2022-08-04 250 }
5320918b9a8786 Dave Airlie 2010-12-15 251
c5c354a3a47280 Takashi Iwai 2022-09-08 252 if (!udl->urbs.count)
c5c354a3a47280 Takashi Iwai 2022-09-08 253 return NULL;
c5c354a3a47280 Takashi Iwai 2022-09-08 254
acd45c56790a3b Takashi Iwai 2022-08-04 255 unode = list_first_entry(&udl->urbs.list, struct urb_node, entry);
Use list_first_entry_or_null() if this list can be empty.
ed9605a66b62f2 Takashi Iwai 2022-09-08 256 list_del_init(&unode->entry);
^^^^^^^^^^^^
dereference.
5320918b9a8786 Dave Airlie 2010-12-15 257 udl->urbs.available--;
5320918b9a8786 Dave Airlie 2010-12-15 258
acd45c56790a3b Takashi Iwai 2022-08-04 @259 return unode ? unode->urb : NULL;
Returns from list_first_entry() should never be checked for NULL.
5320918b9a8786 Dave Airlie 2010-12-15 260 }
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests
next reply other threads:[~2023-05-02 11:19 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-02 11:19 Dan Carpenter [this message]
2023-05-02 11:28 ` Takashi Iwai
2023-05-02 11:38 ` Thomas Zimmermann
2023-05-02 13:02 ` Dan Carpenter
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