Re: [PATCH for-5.10] media: netup_unidvb: Don't leak SPI master in probe error path

From: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
To: Lukas Wunner <lukas@wunner.de>
Cc: Mark Brown <broonie@kernel.org>,
	linux-spi@vger.kernel.org, Kozlov Sergey <serjk@netup.ru>,
	Abylay Ospan <aospan@netup.ru>,
	linux-media@vger.kernel.org
Subject: Re: [PATCH for-5.10] media: netup_unidvb: Don't leak SPI master in probe error path
Date: Mon, 23 Nov 2020 15:06:34 +0100	[thread overview]
Message-ID: <20201123150634.2bd62db7@coco.lan> (raw)
In-Reply-To: <48e6a396526bcd0a26e970036dbe3207cce57ea6.1605512876.git.lukas@wunner.de>

Em Mon, 16 Nov 2020 09:23:13 +0100
Lukas Wunner <lukas@wunner.de> escreveu:

> If the call to spi_register_master() fails on probe of the NetUP
> Universal DVB driver, the spi_master struct is erroneously not freed.
> 
> Likewise, if spi_new_device() fails, the spi_controller struct is
> not unregistered.  Plug the leaks.
> 
> While at it, fix an ordering issue in netup_spi_release() wherein
> spi_unregister_master() is called after fiddling with the IRQ control
> register.  The correct order is to call spi_unregister_master() *before*
> this teardown step because bus accesses may still be ongoing until that
> function returns.
> 
> Fixes: 52b1eaf4c59a ("[media] netup_unidvb: NetUP Universal DVB-S/S2/T/T2/C PCI-E card driver")
> Signed-off-by: Lukas Wunner <lukas@wunner.de>
> Cc: <stable@vger.kernel.org> # v4.3+: 5e844cc37a5c: spi: Introduce device-managed SPI controller allocation
> Cc: <stable@vger.kernel.org> # v4.3+
> Cc: Kozlov Sergey <serjk@netup.ru>
> ---
> @Mauro Carvalho Chehab:
> This patch needs to go in through the spi tree because it depends on
> commit 5e844cc37a5c, which is on the spi/for-5.10 branch.
> Please ack (barring any objections).  Thanks!

Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

I'm OK on having this merged via SPI mailing list.

> 
>  drivers/media/pci/netup_unidvb/netup_unidvb_spi.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/pci/netup_unidvb/netup_unidvb_spi.c b/drivers/media/pci/netup_unidvb/netup_unidvb_spi.c
> index d4f12c250f91..526042d8afae 100644
> --- a/drivers/media/pci/netup_unidvb/netup_unidvb_spi.c
> +++ b/drivers/media/pci/netup_unidvb/netup_unidvb_spi.c
> @@ -175,7 +175,7 @@ int netup_spi_init(struct netup_unidvb_dev *ndev)
>  	struct spi_master *master;
>  	struct netup_spi *nspi;
>  
> -	master = spi_alloc_master(&ndev->pci_dev->dev,
> +	master = devm_spi_alloc_master(&ndev->pci_dev->dev,
>  		sizeof(struct netup_spi));
>  	if (!master) {
>  		dev_err(&ndev->pci_dev->dev,
> @@ -208,6 +208,7 @@ int netup_spi_init(struct netup_unidvb_dev *ndev)
>  		ndev->pci_slot,
>  		ndev->pci_func);
>  	if (!spi_new_device(master, &netup_spi_board)) {
> +		spi_unregister_master(master);
>  		ndev->spi = NULL;
>  		dev_err(&ndev->pci_dev->dev,
>  			"%s(): unable to create SPI device\n", __func__);
> @@ -226,13 +227,13 @@ void netup_spi_release(struct netup_unidvb_dev *ndev)
>  	if (!spi)
>  		return;
>  
> +	spi_unregister_master(spi->master);
>  	spin_lock_irqsave(&spi->lock, flags);
>  	reg = readw(&spi->regs->control_stat);
>  	writew(reg | NETUP_SPI_CTRL_IRQ, &spi->regs->control_stat);
>  	reg = readw(&spi->regs->control_stat);
>  	writew(reg & ~NETUP_SPI_CTRL_IMASK, &spi->regs->control_stat);
>  	spin_unlock_irqrestore(&spi->lock, flags);
> -	spi_unregister_master(spi->master);
>  	ndev->spi = NULL;
>  }
>  

Thanks,
Mauro