Re: [PATCH] bus: hisi_lpc: Don't use devm_kzalloc() to allocate logical PIO range

From: Joe Perches
Date: Fri Jun 14 2019 - 06:09:09 EST

On Fri, 2019-06-14 at 17:47 +0800, John Garry wrote:
> If, after registering a logical PIO range, the driver probe later fails,
> the logical PIO range memory will be released automatically.
> This causes an issue, in that the logical PIO range is not unregistered
> (that is not supported) and the released range memory may be later
> referenced
> Allocate the logical PIO range with kzalloc() to avoid this potential
> issue.
> Fixes: adf38bb0b5956 ("HISI LPC: Support the LPC host on Hip06/Hip07 with DT bindings")
> Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
> diff --git a/drivers/bus/hisi_lpc.c b/drivers/bus/hisi_lpc.c
> @@ -599,7 +599,7 @@ static int hisi_lpc_probe(struct platform_device *pdev)
> if (IS_ERR(lpcdev->membase))
> return PTR_ERR(lpcdev->membase);
> - range = devm_kzalloc(dev, sizeof(*range), GFP_KERNEL);
> + range = kzalloc(sizeof(*range), GFP_KERNEL);

If this is really necessary, it'd be useful to say so in the
code too with a comment so it doesn't get drive-by 'unfixed'
by someone well meaning but ill-uninformed.