| Message ID | 1376066046-16037-3-git-send-email-s.nawrocki@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Quoting Sylwester Nawrocki (2013-08-09 09:34:06) > There is currently a race condition in the device tree part of clk_get() > function, since the pointer returned from of_clk_get_by_name() may become > invalid before __clk_get() call. For example, due to the clock provider > driver remove() callback being called in between of_clk_get_by_name() > and __clk_get(). > > Fix this by doing both the look up and __clk_get() operations with the > clock providers list mutex held. This ensures that the clock pointer > returned from __of_clk_get_from_provider() call and passed to __clk_get() > is valid, as long as the clock supplier module first removes its clock > provider instance and then does clk_unregister() on the corresponding > clocks. > > Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com> > Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Reviewed-by: Mike Turquette <mturquette@linaro.org> I can take this through the clk tree if Russell's ACKs. Regards, Mike > --- > drivers/clk/clkdev.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c > index 442a313..4f5c4ef 100644 > --- a/drivers/clk/clkdev.c > +++ b/drivers/clk/clkdev.c > @@ -39,7 +39,13 @@ struct clk *of_clk_get(struct device_node *np, int index) > if (rc) > return ERR_PTR(rc); > > - clk = of_clk_get_from_provider(&clkspec); > + of_clk_lock(); > + clk = __of_clk_get_from_provider(&clkspec); > + > + if (!IS_ERR(clk) && !__clk_get(clk)) > + clk = ERR_PTR(-ENOENT); > + > + of_clk_unlock(); > of_node_put(clkspec.np); > return clk; > } > @@ -157,7 +163,7 @@ struct clk *clk_get(struct device *dev, const char *con_id) > > if (dev) { > clk = of_clk_get_by_name(dev->of_node, con_id); > - if (!IS_ERR(clk) && __clk_get(clk)) > + if (!IS_ERR(clk)) > return clk; > } > > -- > 1.7.9.5
diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c index 442a313..4f5c4ef 100644 --- a/drivers/clk/clkdev.c +++ b/drivers/clk/clkdev.c @@ -39,7 +39,13 @@ struct clk *of_clk_get(struct device_node *np, int index) if (rc) return ERR_PTR(rc); - clk = of_clk_get_from_provider(&clkspec); + of_clk_lock(); + clk = __of_clk_get_from_provider(&clkspec); + + if (!IS_ERR(clk) && !__clk_get(clk)) + clk = ERR_PTR(-ENOENT); + + of_clk_unlock(); of_node_put(clkspec.np); return clk; } @@ -157,7 +163,7 @@ struct clk *clk_get(struct device *dev, const char *con_id) if (dev) { clk = of_clk_get_by_name(dev->of_node, con_id); - if (!IS_ERR(clk) && __clk_get(clk)) + if (!IS_ERR(clk)) return clk; }