Re: [patch v18 1/4] drivers: jtag: Add JTAG core driver

[Julia Cartwright <juliac@eso.teric.us>]

On Mon, Jan 29, 2018 at 04:31:42PM +0200, Oleksandr Shamray wrote:
> Initial patch for JTAG driver
> JTAG class driver provide infrastructure to support hardware/software
> JTAG platform drivers. It provide user layer API interface for flashing
> and debugging external devices which equipped with JTAG interface
> using standard transactions.
> 
> Driver exposes set of IOCTL to user space for:
> - XFER:
> - SIR (Scan Instruction Register, IEEE 1149.1 Data Register scan);
> - SDR (Scan Data Register, IEEE 1149.1 Instruction Register scan);
> - RUNTEST (Forces the IEEE 1149.1 bus to a run state for a specified
>   number of clocks).
> - SIOCFREQ/GIOCFREQ for setting and reading JTAG frequency.
> 
> Driver core provides set of internal APIs for allocation and
> registration:
> - jtag_register;
> - jtag_unregister;
> - jtag_alloc;
> - jtag_free;
> 
> Platform driver on registration with jtag-core creates the next
> entry in dev folder:
> /dev/jtagX
> 
> Signed-off-by: Oleksandr Shamray <oleksandrs@mellanox.com>
> Signed-off-by: Jiri Pirko <jiri@mellanox.com>
> Acked-by: Philippe Ombredanne <pombredanne@nexb.com>
[..]
> diff --git a/drivers/jtag/jtag.c b/drivers/jtag/jtag.c
[..]
> +struct jtag *jtag_alloc(size_t priv_size, const struct jtag_ops *ops)
> +{
> +	struct jtag *jtag;
> +
> +	jtag = kzalloc(sizeof(*jtag) + priv_size, GFP_KERNEL);
> +	if (!jtag)
> +		return NULL;
> +
> +	if (!ops)
> +		return NULL;
> +
> +	if (!ops->idle || !ops->mode_set || !ops->status_get || !ops->xfer)
> +		return NULL;

Did you think through this?

You leak 'jtag' here and above.

Perform all the ops checks prior to the allocation.

   Julia