Am Dienstag, 29. November 2016, 16:45:18 schrieb Alexander Kochetkov:
> Currently rockchip_timer can be used as a scheduler clock. We properly
> marked rk_timer_sched_clock_read() as notrace but we then call another
> function rk_timer_counter_read() that _wasn't_ notrace.
>
> Having a traceable function in the sched_clock() path leads to a recursion
> within ftrace and a kernel crash.
>
> Fix this by adding an extra notrace function to keep other users of
> rk_timer_counter_read() traceable.
>
> Signed-off-by: Alexander Kochetkov <al.kochet@xxxxxxxxx>
you introduced the issue yourself in patch 11/13. In general any patch should
never leave the kernel in a worse state than it was before, so no patch should
ever introduce known issues itself.
In that line of thought, don't patches 10+11 introduce warnings about unused
functions as well when applied without patch 12?
Maybe merge them?
Heiko
> ---
> drivers/clocksource/rockchip_timer.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/clocksource/rockchip_timer.c
> b/drivers/clocksource/rockchip_timer.c index 1af80a0..a127822 100644
> --- a/drivers/clocksource/rockchip_timer.c
> +++ b/drivers/clocksource/rockchip_timer.c
> @@ -87,7 +87,7 @@ static void rk_timer_update_counter(u64 cycles, struct
> rk_timer *timer) writel_relaxed(upper, timer->base + TIMER_LOAD_COUNT1);
> }
>
> -static u64 rk_timer_counter_read(struct rk_timer *timer)
> +static u64 notrace _rk_timer_counter_read(struct rk_timer *timer)
> {
> u64 counter;
> u32 lower;
> @@ -106,6 +106,11 @@ static u64 rk_timer_counter_read(struct rk_timer
> *timer) return counter;
> }
>
> +static u64 rk_timer_counter_read(struct rk_timer *timer)
> +{
> + return _rk_timer_counter_read(timer);
> +}
> +
> static void rk_timer_interrupt_clear(struct rk_timer *timer)
> {
> writel_relaxed(1, timer->base + TIMER_INT_STATUS);
> @@ -168,7 +173,7 @@ static u64 notrace rk_timer_sched_clock_read(void)
> {
> struct rk_clocksource *_cs = &cs_timer;
>
> - return ~rk_timer_counter_read(&_cs->timer);
> + return ~_rk_timer_counter_read(&_cs->timer);
> }
>
> static int __init rk_timer_init(struct device_node *np, u32 ctrl_reg)
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