Messages in this thread | | | From | Bjorn Helgaas <> | Date | Fri, 14 Jun 2019 08:23:51 -0500 | Subject | Re: [PATCH v2] bus: hisi_lpc: Don't use devm_kzalloc() to allocate logical PIO range |
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[try another address for Zhichang; first one bounced]
On Fri, Jun 14, 2019 at 8:20 AM Bjorn Helgaas <bhelgaas@google.com> wrote: > > [+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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