linux-kernel - [tip:timers/core] clocksource/drivers/ti-32k: Prevent ftrace recursion

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Message-ID: <tip-3aa601492babdf3acdec89e5aa9c44e1a357a4d8@git.kernel.org>
Date:   Thu, 22 Sep 2016 07:54:47 -0700
From:   tip-bot for Jisheng Zhang <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     hpa@...or.com, tglx@...utronix.de, mingo@...nel.org,
        rostedt@...dmis.org, linux-kernel@...r.kernel.org,
        jszhang@...vell.com
Subject: [tip:timers/core] clocksource/drivers/ti-32k: Prevent ftrace
 recursion

Commit-ID:  3aa601492babdf3acdec89e5aa9c44e1a357a4d8
Gitweb:     http://git.kernel.org/tip/3aa601492babdf3acdec89e5aa9c44e1a357a4d8
Author:     Jisheng Zhang <jszhang@...vell.com>
AuthorDate: Thu, 22 Sep 2016 15:56:21 +0800
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Thu, 22 Sep 2016 16:49:19 +0200

clocksource/drivers/ti-32k: Prevent ftrace recursion

Currently ti-32k can be used as a scheduler clock. We properly marked
omap_32k_read_sched_clock() as notrace but we then call another
function ti_32k_read_cycles() 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 ti_32k_read_cycles()
function.

Signed-off-by: Jisheng Zhang <jszhang@...vell.com>
Cc: daniel.lezcano@...aro.org
Cc: linux-arm-kernel@...ts.infradead.org
Cc: Steven Rostedt <rostedt@...dmis.org>
Link: http://lkml.kernel.org/r/20160922075621.3725-1-jszhang@marvell.com
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>

---
 drivers/clocksource/timer-ti-32k.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clocksource/timer-ti-32k.c b/drivers/clocksource/timer-ti-32k.c
index 92b7e39..cf5b14e 100644
--- a/drivers/clocksource/timer-ti-32k.c
+++ b/drivers/clocksource/timer-ti-32k.c
@@ -65,7 +65,7 @@ static inline struct ti_32k *to_ti_32k(struct clocksource *cs)
 	return container_of(cs, struct ti_32k, cs);
 }
 
-static cycle_t ti_32k_read_cycles(struct clocksource *cs)
+static cycle_t notrace ti_32k_read_cycles(struct clocksource *cs)
 {
 	struct ti_32k *ti = to_ti_32k(cs);