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From: Stephen Boyd <sboyd@codeaurora.org>
To: Russell King <linux@arm.linux.org.uk>
Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: sched_clock: Add more notrace to prevent recursion
Date: Thu, 14 Mar 2013 17:08:06 -0700	[thread overview]
Message-ID: <1363306086-23501-1-git-send-email-sboyd@codeaurora.org> (raw)

cyc_to_sched_clock() is called by sched_clock() and cyc_to_ns()
is called by cyc_to_sched_clock(). I suspect that some compilers
inline both of these functions into sched_clock() and so we've
been getting away without having a notrace marking. It seems that
my compiler isn't inlining cyc_to_sched_clock() though, so I'm
hitting a recursion bug when I enable the function graph tracer,
causing my system to crash. Marking these functions notrace fixes
it. Technically cyc_to_ns() doesn't need the notrace because it's
already marked inline, but let's just add it so that if we ever
remove inline from that function it doesn't blow up.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
 arch/arm/kernel/sched_clock.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/kernel/sched_clock.c b/arch/arm/kernel/sched_clock.c
index bd6f56b..59d2adb 100644
--- a/arch/arm/kernel/sched_clock.c
+++ b/arch/arm/kernel/sched_clock.c
@@ -45,12 +45,12 @@ static u32 notrace jiffy_sched_clock_read(void)
 
 static u32 __read_mostly (*read_sched_clock)(void) = jiffy_sched_clock_read;
 
-static inline u64 cyc_to_ns(u64 cyc, u32 mult, u32 shift)
+static inline u64 notrace cyc_to_ns(u64 cyc, u32 mult, u32 shift)
 {
 	return (cyc * mult) >> shift;
 }
 
-static unsigned long long cyc_to_sched_clock(u32 cyc, u32 mask)
+static unsigned long long notrace cyc_to_sched_clock(u32 cyc, u32 mask)
 {
 	u64 epoch_ns;
 	u32 epoch_cyc;
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

WARNING: multiple messages have this Message-ID (diff)
From: sboyd@codeaurora.org (Stephen Boyd)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: sched_clock: Add more notrace to prevent recursion
Date: Thu, 14 Mar 2013 17:08:06 -0700	[thread overview]
Message-ID: <1363306086-23501-1-git-send-email-sboyd@codeaurora.org> (raw)

cyc_to_sched_clock() is called by sched_clock() and cyc_to_ns()
is called by cyc_to_sched_clock(). I suspect that some compilers
inline both of these functions into sched_clock() and so we've
been getting away without having a notrace marking. It seems that
my compiler isn't inlining cyc_to_sched_clock() though, so I'm
hitting a recursion bug when I enable the function graph tracer,
causing my system to crash. Marking these functions notrace fixes
it. Technically cyc_to_ns() doesn't need the notrace because it's
already marked inline, but let's just add it so that if we ever
remove inline from that function it doesn't blow up.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
 arch/arm/kernel/sched_clock.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/kernel/sched_clock.c b/arch/arm/kernel/sched_clock.c
index bd6f56b..59d2adb 100644
--- a/arch/arm/kernel/sched_clock.c
+++ b/arch/arm/kernel/sched_clock.c
@@ -45,12 +45,12 @@ static u32 notrace jiffy_sched_clock_read(void)
 
 static u32 __read_mostly (*read_sched_clock)(void) = jiffy_sched_clock_read;
 
-static inline u64 cyc_to_ns(u64 cyc, u32 mult, u32 shift)
+static inline u64 notrace cyc_to_ns(u64 cyc, u32 mult, u32 shift)
 {
 	return (cyc * mult) >> shift;
 }
 
-static unsigned long long cyc_to_sched_clock(u32 cyc, u32 mask)
+static unsigned long long notrace cyc_to_sched_clock(u32 cyc, u32 mask)
 {
 	u64 epoch_ns;
 	u32 epoch_cyc;
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

             reply	other threads:[~2013-03-15  0:08 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-15  0:08 Stephen Boyd [this message]
2013-03-15  0:08 ` [PATCH] ARM: sched_clock: Add more notrace to prevent recursion Stephen Boyd
2013-03-21 17:49 ` Stephen Boyd
2013-03-21 17:49   ` Stephen Boyd
2013-03-26 17:35   ` Stephen Boyd
2013-03-26 17:35     ` Stephen Boyd
2013-04-18  0:34     ` Stephen Boyd
2013-04-18  0:34       ` Stephen Boyd
2013-04-18  9:20       ` Russell King - ARM Linux
2013-04-18  9:20         ` Russell King - ARM Linux

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