linux-kernel - [PATCH v2] regulator: core: fix kobject release warning and memory leak in regulator

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 16 Nov 2022 15:43:39 +0800
From:   Zeng Heng <zengheng4@...wei.com>
To:     <lgirdwood@...il.com>, <vz@...ia.com>, <broonie@...nel.org>,
        <mirq-linux@...e.qmqm.pl>
CC:     <zengheng4@...wei.com>, <liwei391@...wei.com>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH v2] regulator: core: fix kobject release warning and memory leak in regulator_register()

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@...wei.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