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Date:   Tue, 27 Apr 2021 16:26:00 +0200
From:   Fabio Aiuto <fabioaiuto83@gmail.com>
To:     Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Cc:     rspringer@google.com, toddpoynor@google.com, benchan@chromium.org,
        rcy@google.com, gregkh@linuxfoundation.org,
        linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Staging:gasket:core: Fix a double free in
 gasket_enable_device
Message-ID: <20210427142559.GD1399@agape.jhs>
References: <20210427141129.6207-1-lyl2019@mail.ustc.edu.cn>
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In-Reply-To: <20210427141129.6207-1-lyl2019@mail.ustc.edu.cn>
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Hi Lv,

I fear gasket is no more on staging tree, I think it's no more on
kernel. Try fetch again from remote.

On Tue, Apr 27, 2021 at 07:11:29AM -0700, Lv Yunlong wrote:
> In gasket_enable_device, it calls gasket_interrupt_init().
> Inside gasket_interrupt_init, interrupt_data is allocated via
> kzalloc() and then is assigned to gasket_dev->interrupt_data.
> If the later two kzalloc() failed, interrupt_data will be freed
> and gasket_dev->interrupt_data will point to a freed memory.
> 
> After gasket_enable_device received the error, the freed
> gasket_dev->interrupt_data is freed again in
> gasket_interrupt_cleanup(gasket_dev).
> 
> My patch moves the "gasket_dev->interrupt_data = interrupt_data"
> assignment behind the later kzalloc() all successd, to avoid
> gasket_dev->interrupt_data pointing to a freed memory
> 
> Fixes: 80666096eb78f ("staging: gasket: core: remove static function forward declarations")
> Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
> ---
>  drivers/staging/gasket/gasket_interrupt.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/gasket/gasket_interrupt.c b/drivers/staging/gasket/gasket_interrupt.c
> index 864342acfd86..d4993d7abb87 100644
> --- a/drivers/staging/gasket/gasket_interrupt.c
> +++ b/drivers/staging/gasket/gasket_interrupt.c
> @@ -322,7 +322,6 @@ int gasket_interrupt_init(struct gasket_dev *gasket_dev)
>  	interrupt_data = kzalloc(sizeof(*interrupt_data), GFP_KERNEL);
>  	if (!interrupt_data)
>  		return -ENOMEM;
> -	gasket_dev->interrupt_data = interrupt_data;
>  	interrupt_data->name = driver_desc->name;
>  	interrupt_data->type = driver_desc->interrupt_type;
>  	interrupt_data->pci_dev = gasket_dev->pci_dev;
> @@ -349,6 +348,8 @@ int gasket_interrupt_init(struct gasket_dev *gasket_dev)
>  		return -ENOMEM;
>  	}
>  
> +	gasket_dev->interrupt_data = interrupt_data;
> +
>  	switch (interrupt_data->type) {
>  	case PCI_MSIX:
>  		ret = gasket_interrupt_msix_init(interrupt_data);
> -- 
> 2.25.1
> 
> 
> 

thank you,

fabio