On Wed, Sep 18, 2019 at 3:47 AM Uwe Kleine-König
<u.kleine-koenig@xxxxxxxxxxxxxx> wrote:
>
> Before commit e42ee61017f5 ("of: Let of_for_each_phandle fallback to
> non-negative cell_count") the iterator functions calling
> of_for_each_phandle assumed a cell count of 0 if cells_name was NULL.
> This corner case was missed when implementing the fallback logic in
> e42ee61017f5 and resulted in an endless loop.
>
> Restore the old behaviour of of_count_phandle_with_args() and
> of_parse_phandle_with_args() and add a check to
> of_phandle_iterator_init() to prevent a similar failure as a safety
> precaution. of_parse_phandle_with_args_map() doesn't need a similar fix
> as cells_name isn't NULL there.
>
> Affected drivers are:
> - drivers/base/power/domain.c
> - drivers/base/power/domain.c
> - drivers/clk/ti/clk-dra7-atl.c
> - drivers/hwmon/ibmpowernv.c
> - drivers/i2c/muxes/i2c-demux-pinctrl.c
> - drivers/iommu/mtk_iommu.c
> - drivers/net/ethernet/freescale/fman/mac.c
> - drivers/opp/of.c
> - drivers/perf/arm_dsu_pmu.c
> - drivers/regulator/of_regulator.c
> - drivers/remoteproc/imx_rproc.c
> - drivers/soc/rockchip/pm_domains.c
> - sound/soc/fsl/imx-audmix.c
> - sound/soc/fsl/imx-audmix.c
> - sound/soc/meson/axg-card.c
> - sound/soc/samsung/tm2_wm5110.c
> - sound/soc/samsung/tm2_wm5110.c
>
> Thanks to Geert Uytterhoeven for reporting the issue, Peter Rosin for
> helping pinpoint the actual problem and the testers for confirming this
> fix.
>
> Fixes: e42ee61017f5 ("of: Let of_for_each_phandle fallback to non-negative cell_count")
> Tested-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> Tested-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
> ---
>
> On Wed, Sep 18, 2019 at 08:01:05AM +0000, Peter Rosin wrote:
> > On 2019-09-18 08:38, Uwe Kleine-König wrote:
> > > EXPORT_SYMBOL(of_parse_phandle_with_args);
> > >
> > > @@ -1765,6 +1779,18 @@ int of_count_phandle_with_args(const struct device_node *np, const char *list_na
> > > struct of_phandle_iterator it;
> > > int rc, cur_index = 0;
> > >
> > > + /* If cells_name is NULL we assume a cell count of 0 */
> > > + if (cells_name == NULL) {
> >
> > A couple of nits.
> >
> > I don't know if there are other considerations, but in the previous two
> > hunks you use !cells_name instead of comparing explicitly with NULL.
> > Personally, I find the shorter form more readable, and in the name of
> > consistency bla bla...
>
> Ack, changed to !cells_name here, too.
>
> >
> > Also, the comment explaining this NULL-check didn't really make sense
> > to me until I realized that knowing the cell count to be zero makes
> > counting trivial. Something along those lines should perhaps be in the
> > comment?
>
> You're right, I extended the comment a bit.
>
> > But as I said, these are nits. Feel free to ignore.
>
> I considered resending already anyhow as I fatfingerd my email address.
> this is fixed now, too. Additionally I fixed a typo in one of the
> comments.
>
> Thanks for your feedback.
>
> Best regards
> Uwe
>
> drivers/of/base.c | 35 +++++++++++++++++++++++++++++++++--
> 1 file changed, 33 insertions(+), 2 deletions(-)
Can I get a proper patch please.
Rob
