linux-kernel - Re: [PATCH] can: etas_es58x: fix memory leak in es58x

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Message-ID: <f76805be-c4fb-4846-9fc9-56af859da537@kernel.org>
Date: Mon, 22 Dec 2025 20:07:30 +0100
From: Vincent Mailhol <mailhol@...nel.org>
To: Szymon Wilczek <swilczek.lx@...il.com>, mkl@...gutronix.de
Cc: arunachalam.santhanam@...bosch.com, linux-can@...r.kernel.org,
 linux-kernel@...r.kernel.org,
 syzbot+e8cb6691a7cf68256cb8@...kaller.appspotmail.com
Subject: Re: [PATCH] can: etas_es58x: fix memory leak in es58x_open()

Hi Szymon,

Thanks for the patch.

On 22/12/2025 at 16:42, Szymon Wilczek wrote:
> When es58x_alloc_rx_urbs() fails partway through allocating RX URBs
> (e.g., if usb_submit_urb() fails at iteration i), the function returns
> an error but leaves any previously allocated and anchored URBs leaked.
> 
> The issue is that es58x_open() returns directly on es58x_alloc_rx_urbs()
> failure instead of jumping to the free_urbs label, which would call
> es58x_free_urbs() to clean up any anchored URBs.

The intended logic is that if es58x_alloc_rx_urbs() only partially
succeeds (i.e. submits at least one URB), then you are still able
to continue.

To keep the intended logic, the final:

  return ret;

of es58x_alloc_rx_urbs() should be changed to:

  return 0;

> Fix this by changing 'return ret' to 'goto free_urbs' to ensure proper
> cleanup of all allocated URBs on failure.

If you want to treat a partial allocation of the URBs as a
non-recoverable error, then fine, but this fix is not elegant.

In that case, please do the clean-up in es58x_alloc_rx_urbs() and
update the error message accordingly.

> Fixes: 8537257874e9 ("can: etas_es58x: add core support for ETAS ES58X CAN USB interfaces")
> Reported-by: syzbot+e8cb6691a7cf68256cb8@...kaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=e8cb6691a7cf68256cb8
> Signed-off-by: Szymon Wilczek <swilczek.lx@...il.com>
> ---
>  drivers/net/can/usb/etas_es58x/es58x_core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/can/usb/etas_es58x/es58x_core.c b/drivers/net/can/usb/etas_es58x/es58x_core.c
> index f799233c2b72..d92c37f277d5 100644
> --- a/drivers/net/can/usb/etas_es58x/es58x_core.c
> +++ b/drivers/net/can/usb/etas_es58x/es58x_core.c
> @@ -1784,7 +1784,7 @@ static int es58x_open(struct net_device *netdev)
>  	if (!es58x_dev->opened_channel_cnt) {
>  		ret = es58x_alloc_rx_urbs(es58x_dev);
>  		if (ret)
> -			return ret;
> +			goto free_urbs;
>  
>  		ret = es58x_set_realtime_diff_ns(es58x_dev);
>  		if (ret)

Yours sincerely,
Vincent Mailhol