From: Yuan Can <yuancan@huawei.com>
To: <linus.walleij@linaro.org>, <brgl@bgdev.pl>,
<warthog618@gmail.com>, <linux-gpio@vger.kernel.org>
Cc: <yuancan@huawei.com>
Subject: [PATCH] gpiolib: fix memory leak in gpiochip_setup_dev
Date: Wed, 9 Nov 2022 07:21:32 +0000 [thread overview]
Message-ID: <20221109072132.117903-1-yuancan@huawei.com> (raw)
From: Zeng Heng <zengheng4@huawei.com>
gcdev_register & gcdev_unregister call device_add & device_del to
request/release source. But in device_add, the dev->p allocated by
device_private_init is not released by device_del.
So when calling gcdev_unregister to release gdev, it needs put_device
to release dev in the following.
Otherwise, kmemleak would report memory leak such as below:
unreferenced object 0xffff88810b406400 (size 512):
comm "python3", pid 1682, jiffies 4295346908 (age 24.090s)
hex dump (first 32 bytes):
00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N..........
ff ff ff ff ff ff ff ff a0 5e 23 90 ff ff ff ff .........^#.....
backtrace:
[<00000000a58ee5fe>] kmalloc_trace+0x22/0x110
[<0000000045fe2058>] device_add+0xb34/0x1130
[<00000000d778b45f>] cdev_device_add+0x83/0xe0
[<0000000089f948ed>] gpiolib_cdev_register+0x73/0xa0
[<00000000a3a8a316>] gpiochip_setup_dev+0x1c/0x70
[<00000000787227b4>] gpiochip_add_data_with_key+0x10f6/0x1bf0
[<000000009ac5742c>] devm_gpiochip_add_data_with_key+0x2e/0x80
[<00000000bf2b23d9>] xra1403_probe+0x192/0x1b0 [gpio_xra1403]
[<000000005b5ef2d4>] spi_probe+0xe1/0x140
[<000000002b26f6f1>] really_probe+0x17c/0x3f0
[<00000000dd2dad9c>] __driver_probe_device+0xe3/0x170
[<000000005ca60d2a>] device_driver_attach+0x34/0x80
[<00000000e9db90db>] bind_store+0x10b/0x1a0
[<00000000e2650f8a>] drv_attr_store+0x49/0x70
[<0000000080a80b2b>] sysfs_kf_write+0x8c/0xb0
[<00000000a28b45b9>] kernfs_fop_write_iter+0x216/0x2e0
unreferenced object 0xffff888100de9800 (size 512):
comm "python3", pid 264, jiffies 4294737615 (age 33.514s)
hex dump (first 32 bytes):
00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N..........
ff ff ff ff ff ff ff ff a0 5e 63 a1 ff ff ff ff .........^c.....
backtrace:
[<00000000bcc571d0>] kmalloc_trace+0x22/0x110
[<00000000eeb06124>] device_add+0xb34/0x1130
[<000000007e5cd2fd>] cdev_device_add+0x83/0xe0
[<000000008f6bcd3a>] gpiolib_cdev_register+0x73/0xa0
[<0000000012c93b24>] gpiochip_setup_dev+0x1c/0x70
[<00000000a24b646a>] gpiochip_add_data_with_key+0x10f6/0x1bf0
[<000000000c225212>] tpic2810_probe+0x16e/0x196 [gpio_tpic2810]
[<00000000b52d04ff>] i2c_device_probe+0x651/0x680
[<0000000058d3ff6b>] really_probe+0x17c/0x3f0
[<00000000586f43d3>] __driver_probe_device+0xe3/0x170
[<000000003f428602>] device_driver_attach+0x34/0x80
[<0000000040e91a1b>] bind_store+0x10b/0x1a0
[<00000000c1d990b9>] drv_attr_store+0x49/0x70
[<00000000a23bfc22>] sysfs_kf_write+0x8c/0xb0
[<00000000064e6572>] kernfs_fop_write_iter+0x216/0x2e0
[<00000000026ce093>] vfs_write+0x658/0x810
Because at the point of gpiochip_setup_dev here, where dev.release
does not set yet, calling put_device would cause the warning of
no release function and double-free in the following fault handler
route (when kfree dev_name). So directly calling kfree to release
dev->p here in case of memory leak.
Fixes: 1f5eb8b17f02 ("gpiolib: fix sysfs when cdev is not selected")
Signed-off-by: Zeng Heng <zengheng4@huawei.com>
---
drivers/gpio/gpiolib.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 4756ea08894f..fa659af86d07 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -539,6 +539,7 @@ static int gpiochip_setup_dev(struct gpio_device *gdev)
err_remove_device:
gcdev_unregister(gdev);
+ kfree(gdev->dev.p);
return ret;
}
--
2.17.1
next reply other threads:[~2022-11-09 7:23 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-09 7:21 Yuan Can [this message]
-- strict thread matches above, loose matches on Subject: below --
2022-11-08 11:53 [PATCH] gpiolib: fix memory leak in gpiochip_setup_dev Zeng Heng
2022-11-08 16:57 ` Kent Gibson
2022-11-09 5:12 ` Kent Gibson
2022-11-09 8:27 ` Zeng Heng
2022-11-09 9:06 ` Kent Gibson
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