Re: [PATCH] iio: accel: kxcjk-1013: Fix possible memory leak in probe and remove

From: Hans de Goede <hdegoede@redhat.com>
To: Yang Yingliang <yangyingliang@huawei.com>,
	linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org
Cc: lars@metafoo.de, jic23@kernel.org,
	andriy.shevchenko@linux.intel.com, ddvlad@gmail.com
Subject: Re: [PATCH] iio: accel: kxcjk-1013: Fix possible memory leak in probe and remove
Date: Thu, 14 Oct 2021 10:20:34 +0200	[thread overview]
Message-ID: <1a3a5582-51b0-4c58-ad6a-a58025054128@redhat.com> (raw)
In-Reply-To: <20211014035338.3750416-1-yangyingliang@huawei.com>

Hi,

On 10/14/21 5:53 AM, Yang Yingliang wrote:
> When ACPI type is ACPI_SMO8500, the data->dready_trig will not be set, the
> memory allocated by iio_triggered_buffer_setup() will not be freed, and cause
> memory leak as follows:
> 
> unreferenced object 0xffff888009551400 (size 512):
>   comm "i2c-SMO8500-125", pid 911, jiffies 4294911787 (age 83.852s)
>   hex dump (first 32 bytes):
>     02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>     00 00 00 00 00 00 00 00 20 e2 e5 c0 ff ff ff ff  ........ .......
>   backtrace:
>     [<0000000041ce75ee>] kmem_cache_alloc_trace+0x16d/0x360
>     [<000000000aeb17b0>] iio_kfifo_allocate+0x41/0x130 [kfifo_buf]
>     [<000000004b40c1f5>] iio_triggered_buffer_setup_ext+0x2c/0x210 [industrialio_triggered_buffer]
>     [<000000004375b15f>] kxcjk1013_probe+0x10c3/0x1d81 [kxcjk_1013]
>     [<0000000020115b9a>] i2c_device_probe+0xa31/0xbe0
>     [<00000000d9f581a6>] really_probe+0x299/0xc30
>     [<00000000c6c16cde>] __driver_probe_device+0x357/0x500
>     [<00000000909852a1>] driver_probe_device+0x4e/0x140
>     [<000000008419ba53>] __device_attach_driver+0x257/0x340
>     [<00000000533bb466>] bus_for_each_drv+0x166/0x1e0
>     [<000000005bf45d75>] __device_attach+0x272/0x420
>     [<0000000075220311>] bus_probe_device+0x1eb/0x2a0
>     [<0000000015587e85>] device_add+0xbf0/0x1f90
>     [<0000000086901b9e>] i2c_new_client_device+0x622/0xb20
>     [<000000000865ca18>] new_device_store+0x1fa/0x420
>     [<0000000059a3d183>] dev_attr_store+0x58/0x80
> 
> Fix it by remove data->dready_trig condition in probe and remove.
> 
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Fixes: a25691c1f967 ("iio: accel: kxcjk1013: allow using an external trigger")
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>

Hmm, wouldn't the right fix be to also move the
iio_triggered_buffer_setup() call to inside the:

	if (client->irq > 0 && data->acpi_type != ACPI_SMO8500) {
	}

block ?

Jonathan (jic23) can you take a look at this, to me it seems that having
a triggered buffer allocated without any triggers is not useful ?

Regards,

Hans

> ---
>  drivers/iio/accel/kxcjk-1013.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iio/accel/kxcjk-1013.c b/drivers/iio/accel/kxcjk-1013.c
> index a51fdd3c9b5b..24c9387c2968 100644
> --- a/drivers/iio/accel/kxcjk-1013.c
> +++ b/drivers/iio/accel/kxcjk-1013.c
> @@ -1595,8 +1595,7 @@ static int kxcjk1013_probe(struct i2c_client *client,
>  	return 0;
>  
>  err_buffer_cleanup:
> -	if (data->dready_trig)
> -		iio_triggered_buffer_cleanup(indio_dev);
> +	iio_triggered_buffer_cleanup(indio_dev);
>  err_trigger_unregister:
>  	if (data->dready_trig)
>  		iio_trigger_unregister(data->dready_trig);
> @@ -1618,8 +1617,8 @@ static int kxcjk1013_remove(struct i2c_client *client)
>  	pm_runtime_disable(&client->dev);
>  	pm_runtime_set_suspended(&client->dev);
>  
> +	iio_triggered_buffer_cleanup(indio_dev);
>  	if (data->dready_trig) {
> -		iio_triggered_buffer_cleanup(indio_dev);
>  		iio_trigger_unregister(data->dready_trig);
>  		iio_trigger_unregister(data->motion_trig);
>  	}
> 