Messages in this thread | | | Date | Tue, 26 Jun 2018 09:24:13 +0200 | From | Boris Brezillon <> | Subject | Re: [PATCH] mtd: rawnand: mxc: remove __init qualifier from mxcnd_probe_dt |
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On Tue, 26 Jun 2018 09:10:05 +0200 Miquel Raynal <miquel.raynal@bootlin.com> wrote:
> Hi Martin, Boris, > > On Fri, 22 Jun 2018 16:50:25 +0200, Martin Kaiser <martin@kaiser.cx> > wrote: > > > mxcnd_probe_dt is called from mxcnd_probe, which is not marked as __init. > > > > I think this line is just a side note and should be at the end of the > commit log. > > > Using the sysfs unbind, bind nodes, mxcnd_probe and mxcnd_probe_dt can > > potentially be called at any time. After the __init functions are cleaned, > > mxcnd_probe_dt is no longer available. Calling it anyway causes a crash. > > The above paragraph explains the problem and the solution, you can just > add something like "mcvnd_probe is untouched because it is already not > marked as __init" instead of the first line. > > > > > Signed-off-by: Martin Kaiser <martin@kaiser.cx> > > Boris, do you think this patch is a good candidate for stable? > > If yes, Martin, could you please add a couple of stable/fixes tags above > your SoB?
We should at least have a Fixes tag. For the stable one, I'm not so sure because the bug does not exist in practice (the compiler always inline mxcnd_probe_dt()).
> > Thanks, > Miquèl > > > --- > > I hope that my understanding is correct. > > > > In practice, I could not get the kernel to crash, my compiler would > > inline mxcnd_probe_dt into mxcnd_probe and ignore the __init. > > > > If I marked mxcnd_probe_dt as noinline, I could trigger a crash as > > follows > > > > [root@host ]# echo bb000000.nand > /sys/bus/platform/drivers/mxc_nand/unbind > > [root@host ]# echo bb000000.nand > /sys/bus/platform/drivers/mxc_nand/bind > > Internal error: Oops - undefined instruction: 0 [#1] ARM > > ... > > > > drivers/mtd/nand/raw/mxc_nand.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/mtd/nand/raw/mxc_nand.c b/drivers/mtd/nand/raw/mxc_nand.c > > index 26cef21..90cfb5e 100644 > > --- a/drivers/mtd/nand/raw/mxc_nand.c > > +++ b/drivers/mtd/nand/raw/mxc_nand.c > > @@ -1686,7 +1686,7 @@ static const struct of_device_id mxcnd_dt_ids[] = { > > }; > > MODULE_DEVICE_TABLE(of, mxcnd_dt_ids); > > > > -static int __init mxcnd_probe_dt(struct mxc_nand_host *host) > > +static int mxcnd_probe_dt(struct mxc_nand_host *host) > > { > > struct device_node *np = host->dev->of_node; > > const struct of_device_id *of_id = > > @@ -1700,7 +1700,7 @@ static int __init mxcnd_probe_dt(struct mxc_nand_host *host) > > return 0; > > } > > #else > > -static int __init mxcnd_probe_dt(struct mxc_nand_host *host) > > +static int mxcnd_probe_dt(struct mxc_nand_host *host) > > { > > return 1; > > }
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