[PATCH 5.7 044/393] regulator: fix memory leak on error path of regulator_register()

From: Vladimir Zapolskiy vz@mleia.com

[ Upstream commit 9177514ce34902b3adb2abd490b6ad05d1cfcb43 ]

The change corrects registration and deregistration on error path of a regulator, the problem was manifested by a reported memory leak on deferred probe:

as3722-regulator as3722-regulator: regulator 13 register failed -517

# cat /sys/kernel/debug/kmemleak unreferenced object 0xecc43740 (size 64): comm "swapper/0", pid 1, jiffies 4294937640 (age 712.880s) hex dump (first 32 bytes): 72 65 67 75 6c 61 74 6f 72 2e 32 34 00 5a 5a 5a regulator.24.ZZZ 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ backtrace: [<0c4c3d1c>] __kmalloc_track_caller+0x15c/0x2c0 [<40c0ad48>] kvasprintf+0x64/0xd4 [<109abd29>] kvasprintf_const+0x70/0x84 [<c4215946>] kobject_set_name_vargs+0x34/0xa8 [<62282ea2>] dev_set_name+0x40/0x64 [<a39b6757>] regulator_register+0x3a4/0x1344 [<16a9543f>] devm_regulator_register+0x4c/0x84 [<51a4c6a1>] as3722_regulator_probe+0x294/0x754 ...

The memory leak problem was introduced as a side ef another fix in regulator_register() error path, I believe that the proper fix is to decouple device_register() function into its two compounds and initialize a struct device before assigning any values to its fields and then using it before actual registration of a device happens.

This lets to call put_device() safely after initialization, and, since now a release callback is called, kfree(rdev->constraints) shall be removed to exclude a double free condition.

Fixes: a3cde9534ebd ("regulator: core: fix regulator_register() error paths to properly release rdev") Signed-off-by: Vladimir Zapolskiy vz@mleia.com Cc: Wen Yang wenyang@linux.alibaba.com Link: https://lore.kernel.org/r/20200724005013.23278-1-vz@mleia.com Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/regulator/core.c | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 7486f6e4e613c..0cb99bb090ef8 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -5005,7 +5005,6 @@ regulator_register(const struct regulator_desc *regulator_desc, struct regulator_dev *rdev; bool dangling_cfg_gpiod = false; bool dangling_of_gpiod = false; - bool reg_device_fail = false; struct device *dev; int ret, i;

@@ -5134,10 +5133,12 @@ regulator_register(const struct regulator_desc *regulator_desc, }

/* register with sysfs */ + device_initialize(&rdev->dev); rdev->dev.class = &regulator_class; rdev->dev.parent = dev; dev_set_name(&rdev->dev, "regulator.%lu", (unsigned long) atomic_inc_return(&regulator_no)); + dev_set_drvdata(&rdev->dev, rdev);

/* set regulator constraints */ if (init_data) @@ -5188,12 +5189,9 @@ regulator_register(const struct regulator_desc *regulator_desc, !rdev->desc->fixed_uV) rdev->is_switch = true;

- dev_set_drvdata(&rdev->dev, rdev); - ret = device_register(&rdev->dev); - if (ret != 0) { - reg_device_fail = true; + ret = device_add(&rdev->dev); + if (ret != 0) goto unset_supplies; - }

rdev_init_debugfs(rdev);

@@ -5215,17 +5213,15 @@ regulator_register(const struct regulator_desc *regulator_desc, mutex_unlock(&regulator_list_mutex); wash: kfree(rdev->coupling_desc.coupled_rdevs); - kfree(rdev->constraints); 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 (reg_device_fail) - put_device(&rdev->dev); - else - kfree(rdev); + kfree(rdev); kfree(config); rinse: if (dangling_cfg_gpiod)