* [PATCH] time: sched_clock: fix integer overflow
@ 2013-07-17 9:46 Baruch Siach
2013-07-29 5:59 ` Baruch Siach
0 siblings, 1 reply; 4+ messages in thread
From: Baruch Siach @ 2013-07-17 9:46 UTC (permalink / raw)
To: John Stultz, Thomas Gleixner
Cc: linux-kernel, linux-arm-kernel, linux-xtensa, Baruch Siach
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
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] time: sched_clock: fix integer overflow
2013-07-17 9:46 [PATCH] time: sched_clock: fix integer overflow Baruch Siach
@ 2013-07-29 5:59 ` Baruch Siach
2013-07-29 18:41 ` Stephen Boyd
2013-08-12 3:03 ` [Linux-Xtensa] " Baruch Siach
0 siblings, 2 replies; 4+ messages in thread
From: Baruch Siach @ 2013-07-29 5:59 UTC (permalink / raw)
To: John Stultz, Thomas Gleixner; +Cc: linux-kernel, linux-arm-kernel, linux-xtensa
Hi Thomas, John,
On Wed, Jul 17, 2013 at 12:46:53PM +0300, Baruch Siach wrote:
> 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.
Ping? -rc3 is out, and this bug (which currently breaks xtensa) is not fixed
yet. Please consider applying.
baruch
> 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. */
> --
--
http://baruch.siach.name/blog/ ~. .~ Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
- baruch@tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] time: sched_clock: fix integer overflow
2013-07-29 5:59 ` Baruch Siach
@ 2013-07-29 18:41 ` Stephen Boyd
2013-08-12 3:03 ` [Linux-Xtensa] " Baruch Siach
1 sibling, 0 replies; 4+ messages in thread
From: Stephen Boyd @ 2013-07-29 18:41 UTC (permalink / raw)
To: Baruch Siach
Cc: John Stultz, Thomas Gleixner, linux-xtensa, linux-kernel,
linux-arm-kernel
On 07/28/13 22:59, Baruch Siach wrote:
> Hi Thomas, John,
>
> On Wed, Jul 17, 2013 at 12:46:53PM +0300, Baruch Siach wrote:
>> 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.
> Ping? -rc3 is out, and this bug (which currently breaks xtensa) is not fixed
> yet. Please consider applying.
Looks good to me.
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
>
>> 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. */
>> --
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Linux-Xtensa] Re: [PATCH] time: sched_clock: fix integer overflow
2013-07-29 5:59 ` Baruch Siach
2013-07-29 18:41 ` Stephen Boyd
@ 2013-08-12 3:03 ` Baruch Siach
1 sibling, 0 replies; 4+ messages in thread
From: Baruch Siach @ 2013-08-12 3:03 UTC (permalink / raw)
To: John Stultz, Thomas Gleixner; +Cc: linux-xtensa, linux-kernel, linux-arm-kernel
Hi Thomas, John,
On Mon, Jul 29, 2013 at 08:59:39AM +0300, Baruch Siach wrote:
> On Wed, Jul 17, 2013 at 12:46:53PM +0300, Baruch Siach wrote:
> > 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.
>
> Ping? -rc3 is out, and this bug (which currently breaks xtensa) is not fixed
> yet. Please consider applying.
Sorry to bother again, but -rc5 is here and xtensa sched_clock is still
broken.
baruch
> > 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. */
> > --
--
http://baruch.siach.name/blog/ ~. .~ Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
- baruch@tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2013-08-12 3:03 UTC | newest]
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2013-07-17 9:46 [PATCH] time: sched_clock: fix integer overflow Baruch Siach
2013-07-29 5:59 ` Baruch Siach
2013-07-29 18:41 ` Stephen Boyd
2013-08-12 3:03 ` [Linux-Xtensa] " Baruch Siach
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