From: Jisheng Zhang <jszhang@marvell.com>
Date: Tue, 20 Oct 2015 08:02:35 +0000 (+0800)
Subject: clocksource/drivers/samsung_pwm_timer: Prevent ftrace recursion
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=b8725dab66f0b2d57affb33a7f6ca094d9f1f8dd;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

clocksource/drivers/samsung_pwm_timer: Prevent ftrace recursion

Currently samsung_pwm_timer can be used as a scheduler clock. We properly
marked samsung_read_sched_clock() as notrace but we then call another
function samsung_clocksource_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 notrace attribute to the samsung_clocksource_read()
function.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---

diff --git a/drivers/clocksource/samsung_pwm_timer.c b/drivers/clocksource/samsung_pwm_timer.c
index bc90e13338cc..9502bc4c3f6d 100644
--- a/drivers/clocksource/samsung_pwm_timer.c
+++ b/drivers/clocksource/samsung_pwm_timer.c
@@ -307,7 +307,7 @@ static void samsung_clocksource_resume(struct clocksource *cs)
 	samsung_time_start(pwm.source_id, true);
 }
 
-static cycle_t samsung_clocksource_read(struct clocksource *c)
+static cycle_t notrace samsung_clocksource_read(struct clocksource *c)
 {
 	return ~readl_relaxed(pwm.source_reg);
 }