From mboxrd@z Thu Jan 1 00:00:00 1970 From: sboyd@codeaurora.org (Stephen Boyd) Date: Mon, 29 Jul 2013 11:41:41 -0700 Subject: [PATCH] time: sched_clock: fix integer overflow In-Reply-To: <20130729055939.GK5161@tarshish> References: <232c026d1b8d2556679aea56cf77a6811f9a96c5.1374054369.git.baruch@tkos.co.il> <20130729055939.GK5161@tarshish> Message-ID: <51F6B765.9030404@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 > >> Reported-by: Max Filippov >> Tested-by: Max Filippov >> Acked-by: Russell King >> Signed-off-by: Baruch Siach >> --- >> 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