Here is a warning report about lack of registered release()
from kobject lib:

Device '(null)' does not have a release() function, it is broken and must be fixed.
WARNING: CPU: 0 PID: 48430 at drivers/base/core.c:2332 device_release+0x104/0x120
Call Trace:
 kobject_put+0xdc/0x180
 put_device+0x1b/0x30
 regulator_register+0x651/0x1170
 devm_regulator_register+0x4f/0xb0

When regulator_register() returns fail and directly goto `clean` symbol,
rdev->dev has not registered release() function yet (which is registered
by regulator_class in the following), so rdev needs to be freed manually.
If rdev->dev.of_node is not NULL, which means the of_node has gotten by
regulator_of_get_init_data(), it needs to call of_node_put() to avoid
refcount leak.

Otherwise, only calling put_device() would lead memory leak of rdev
in further:

unreferenced object 0xffff88810d0b1000 (size 2048):
  comm "107-i2c-rtq6752", pid 48430, jiffies 4342258431 (age 1341.780s)
  backtrace:
    kmalloc_trace+0x22/0x110
    regulator_register+0x184/0x1170
    devm_regulator_register+0x4f/0xb0

When regulator_register() returns fail and goto `wash` symbol,
rdev->dev has registered release() function, so directly call
put_device() to cleanup everything.

Fixes: d3c731564e09 ("regulator: plug of_node leak in regulator_register()'s error path")
Signed-off-by: Zeng Heng <zengheng4@huawei.com>
---
 drivers/regulator/core.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index bcccad8f7516..77126cb1ae8c 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -5644,11 +5644,15 @@ regulator_register(const struct regulator_desc *regulator_desc,
 	mutex_lock(&regulator_list_mutex);
 	regulator_ena_gpio_free(rdev);
 	mutex_unlock(&regulator_list_mutex);
+	put_device(&rdev->dev);
+	rdev = NULL;
 clean:
 	if (dangling_of_gpiod)
 		gpiod_put(config->ena_gpiod);
+	if (rdev && rdev->dev.of_node)
+		of_node_put(rdev->dev.of_node);
+	kfree(rdev);
 	kfree(config);
-	put_device(&rdev->dev);
 rinse:
 	if (dangling_cfg_gpiod)
 		gpiod_put(cfg->ena_gpiod);
-- 
2.25.1

On Wed, 16 Nov 2022 15:43:39 +0800, Zeng Heng wrote:
> Here is a warning report about lack of registered release()
> from kobject lib:
> 
> Device '(null)' does not have a release() function, it is broken and must be fixed.
> WARNING: CPU: 0 PID: 48430 at drivers/base/core.c:2332 device_release+0x104/0x120
> Call Trace:
>  kobject_put+0xdc/0x180
>  put_device+0x1b/0x30
>  regulator_register+0x651/0x1170
>  devm_regulator_register+0x4f/0xb0
> 
> [...]

Applied to

   broonie/regulator.git for-next

Thanks!

[1/1] regulator: core: fix kobject release warning and memory leak in regulator_register()
      commit: 5f4b204b6b8153923d5be8002c5f7082985d153f

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark