linux-kernel - Re: [RESEND PATCH v5 2/3] test_firmware: fix a memory leak with reqs buffer

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Date:   Fri, 12 May 2023 14:34:29 +0200
From:   Mirsad Todorovac <mirsad.todorovac@....unizg.hr>
To:     linux-kernel@...r.kernel.org
Cc:     Luis Chamberlain <mcgrof@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Russ Weight <russell.h.weight@...el.com>,
        Tianfei Zhang <tianfei.zhang@...el.com>,
        Shuah Khan <shuah@...nel.org>,
        Colin Ian King <colin.i.king@...il.com>,
        Randy Dunlap <rdunlap@...radead.org>,
        linux-kselftest@...r.kernel.org, stable@...r.kernel.org,
        Dan Carpenter <error27@...il.com>, Takashi Iwai <tiwai@...e.de>
Subject: Re: [RESEND PATCH v5 2/3] test_firmware: fix a memory leak with reqs
 buffer

Hi Dan,

On 5/9/23 10:47, Mirsad Goran Todorovac wrote:
> Dan Carpenter spotted that test_fw_config->reqs will be leaked if
> trigger_batched_requests_store() is called two or more times.
> The same appears with trigger_batched_requests_async_store().
> 
> This bug wasn't trigger by the tests, but observed by Dan's visual
> inspection of the code.
> 
> The recommended workaround was to return -EBUSY if test_fw_config->reqs
> is already allocated.
> 
> Fixes: 7feebfa487b92 ("test_firmware: add support for request_firmware_into_buf")
> Cc: Luis Chamberlain <mcgrof@...nel.org>
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Cc: Russ Weight <russell.h.weight@...el.com>
> Cc: Tianfei Zhang <tianfei.zhang@...el.com>
> Cc: Shuah Khan <shuah@...nel.org>
> Cc: Colin Ian King <colin.i.king@...il.com>
> Cc: Randy Dunlap <rdunlap@...radead.org>
> Cc: linux-kselftest@...r.kernel.org
> Cc: stable@...r.kernel.org # v5.4
> Suggested-by: Dan Carpenter <error27@...il.com>
> Suggested-by: Takashi Iwai <tiwai@...e.de>
> Signed-off-by: Mirsad Goran Todorovac <mirsad.todorovac@....unizg.hr>
> ---
>   lib/test_firmware.c | 10 ++++++++++
>   1 file changed, 10 insertions(+)
> 
> diff --git a/lib/test_firmware.c b/lib/test_firmware.c
> index 35417e0af3f4..91b232ed3161 100644
> --- a/lib/test_firmware.c
> +++ b/lib/test_firmware.c
> @@ -913,6 +913,11 @@ static ssize_t trigger_batched_requests_store(struct device *dev,
>   
>   	mutex_lock(&test_fw_mutex);
>   
> +	if (test_fw_config->reqs) {
> +		rc = -EBUSY;
> +		goto out_bail;
> +	}
> +
>   	test_fw_config->reqs =
>   		vzalloc(array3_size(sizeof(struct test_batched_req),
>   				    test_fw_config->num_requests, 2));
> @@ -1011,6 +1016,11 @@ ssize_t trigger_batched_requests_async_store(struct device *dev,
>   
>   	mutex_lock(&test_fw_mutex);
>   
> +	if (test_fw_config->reqs) {
> +		rc = -EBUSY;
> +		goto out_bail;
> +	}
> +
>   	test_fw_config->reqs =
>   		vzalloc(array3_size(sizeof(struct test_batched_req),
>   				    test_fw_config->num_requests, 2));

I was just thinking, since returning -EBUSY for the case of already allocated
test_fw_config->reqs was your suggestion and your idea, maybe it would be OK
to properly reflect that in Co-developed-by: or Signed-off-by: , but if I
understood well, the CoC requires that I am explicitly approved of those?

Thanks,
Mirsad

-- 
Mirsad Goran Todorovac
Sistem inženjer
Grafički fakultet | Akademija likovnih umjetnosti
Sveučilište u Zagrebu

System engineer
Faculty of Graphic Arts | Academy of Fine Arts
University of Zagreb, Republic of Croatia

"What’s this thing suddenly coming towards me very fast? Very very fast.
... I wonder if it will be friends with me?"