Messages in this thread | | | From | Bjorn Helgaas <> | Date | Fri, 14 Jun 2019 08:20:10 -0500 | Subject | Re: [PATCH v2] bus: hisi_lpc: Don't use devm_kzalloc() to allocate logical PIO range |
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[+cc Zhichang, logic_pio author]
On Fri, Jun 14, 2019 at 5:26 AM John Garry <john.garry@huawei.com> 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@huawei.com> > --- > > Change to v1: > - add comment, as advised by Joe Perches > > diff --git a/drivers/bus/hisi_lpc.c b/drivers/bus/hisi_lpc.c > index 19d7b6ff2f17..5f0130a693fe 100644 > --- a/drivers/bus/hisi_lpc.c > +++ b/drivers/bus/hisi_lpc.c > @@ -599,7 +599,8 @@ 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); > + /* Logical PIO may reference 'range' memory even if the probe fails */ > + range = kzalloc(sizeof(*range), GFP_KERNEL);
This doesn't feel like the correct way to fix this. If the probe fails, everything done by the probe should be undone, including the allocation and registration of "range". I don't know what the best mechanism is, but I'm skeptical about this one.
> if (!range) > return -ENOMEM; > > @@ -610,6 +611,7 @@ static int hisi_lpc_probe(struct platform_device *pdev) > ret = logic_pio_register_range(range); > if (ret) { > dev_err(dev, "register IO range failed (%d)!\n", ret); > + kfree(range); > return ret; > } > lpcdev->io_host = range; > -- > 2.17.1 >
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