Re: [PATCH v2 4/4] clkdev: Fix race condition in clock lookup fromdevice tree

From: Russell King - ARM Linux
Date: Tue Aug 20 2013 - 17:54:17 EST


On Tue, Aug 20, 2013 at 07:34:23PM +0200, Sylwester Nawrocki wrote:
> 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. I.e. 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@xxxxxxxxxxx>
> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> Reviewed-by: Mike Turquette <mturquette@xxxxxxxxxx>

Thanks.

Acked-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
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