From: khilman@linaro.org (Kevin Hilman)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/2] sched/nohz: fix overflow error in scheduler_tick_max_deferment()
Date: Mon, 16 Sep 2013 15:43:49 -0700 [thread overview]
Message-ID: <1379371429-22214-2-git-send-email-khilman@linaro.org> (raw)
In-Reply-To: <1379371429-22214-1-git-send-email-khilman@linaro.org>
The conversion of the max deferment from usecs to nsecs can easily
overflow on platforms where a long is 32-bits. To fix, cast the usecs
value to u64 before multiplying by NSECS_PER_USEC.
This was discovered on 32-bit ARM platform when extending the max
deferment value.
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Kevin Hilman <khilman@linaro.org>
---
kernel/sched/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 4b1fe3e..3d7c80e 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2203,7 +2203,7 @@ u64 scheduler_tick_max_deferment(void)
if (time_before_eq(next, now))
return 0;
- return jiffies_to_usecs(next - now) * NSEC_PER_USEC;
+ return (u64)jiffies_to_usecs(next - now) * NSEC_PER_USEC;
}
static __init int sched_nohz_full_init_debug(void)
--
1.8.3
next prev parent reply other threads:[~2013-09-16 22:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-16 22:43 [PATCH 1/2] sched/nohz: add debugfs control over sched_tick_max_deferment Kevin Hilman
2013-09-16 22:43 ` Kevin Hilman [this message]
2013-11-18 21:42 ` Kevin Hilman
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