From: Baruch Siach <baruch@tkos.co.il>
To: John Stultz <john.stultz@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-xtensa@linux-xtensa.org, Baruch Siach <baruch@tkos.co.il>
Subject: [PATCH] time: sched_clock: fix integer overflow
Date: Wed, 17 Jul 2013 12:46:53 +0300 [thread overview]
Message-ID: <232c026d1b8d2556679aea56cf77a6811f9a96c5.1374054369.git.baruch@tkos.co.il> (raw)
The expression '(1 << 32)' happens to evaluate as 0 on ARM, but it evaluates as
1 on xtensa and x86_64. This zeros sched_clock_mask, and breaks sched_clock().
Set the type of 1 to 'unsigned long long' to get the value we need.
Reported-by: Max Filippov <jcmvbkbc@gmail.com>
Tested-by: Max Filippov <jcmvbkbc@gmail.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
---
kernel/time/sched_clock.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c
index a326f27..0b479a6 100644
--- a/kernel/time/sched_clock.c
+++ b/kernel/time/sched_clock.c
@@ -121,7 +121,7 @@ void __init setup_sched_clock(u32 (*read)(void), int bits, unsigned long rate)
BUG_ON(bits > 32);
WARN_ON(!irqs_disabled());
read_sched_clock = read;
- sched_clock_mask = (1 << bits) - 1;
+ sched_clock_mask = (1ULL << bits) - 1;
cd.rate = rate;
/* calculate the mult/shift to convert counter ticks to ns. */
--
1.8.3.2
WARNING: multiple messages have this Message-ID (diff)
From: baruch@tkos.co.il (Baruch Siach)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] time: sched_clock: fix integer overflow
Date: Wed, 17 Jul 2013 12:46:53 +0300 [thread overview]
Message-ID: <232c026d1b8d2556679aea56cf77a6811f9a96c5.1374054369.git.baruch@tkos.co.il> (raw)
The expression '(1 << 32)' happens to evaluate as 0 on ARM, but it evaluates as
1 on xtensa and x86_64. This zeros sched_clock_mask, and breaks sched_clock().
Set the type of 1 to 'unsigned long long' to get the value we need.
Reported-by: Max Filippov <jcmvbkbc@gmail.com>
Tested-by: Max Filippov <jcmvbkbc@gmail.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
---
kernel/time/sched_clock.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c
index a326f27..0b479a6 100644
--- a/kernel/time/sched_clock.c
+++ b/kernel/time/sched_clock.c
@@ -121,7 +121,7 @@ void __init setup_sched_clock(u32 (*read)(void), int bits, unsigned long rate)
BUG_ON(bits > 32);
WARN_ON(!irqs_disabled());
read_sched_clock = read;
- sched_clock_mask = (1 << bits) - 1;
+ sched_clock_mask = (1ULL << bits) - 1;
cd.rate = rate;
/* calculate the mult/shift to convert counter ticks to ns. */
--
1.8.3.2
next reply other threads:[~2013-07-17 10:07 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-17 9:46 Baruch Siach [this message]
2013-07-17 9:46 ` [PATCH] time: sched_clock: fix integer overflow Baruch Siach
2013-07-29 5:59 ` Baruch Siach
2013-07-29 5:59 ` Baruch Siach
2013-07-29 18:41 ` Stephen Boyd
2013-07-29 18:41 ` Stephen Boyd
2013-08-12 3:03 ` [Linux-Xtensa] " Baruch Siach
2013-08-12 3:03 ` Baruch Siach
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