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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Odin Ugedal <odin@uged.al>, Peter Zijlstra <peterz@infradead.org>,
	Ben Segall <bsegall@google.com>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 4.19 39/39] sched/fair: Fix CFS bandwidth hrtimer expiry type
Date: Wed, 14 Jul 2021 15:46:24 -0400	[thread overview]
Message-ID: <20210714194625.55303-39-sashal@kernel.org> (raw)
In-Reply-To: <20210714194625.55303-1-sashal@kernel.org>

From: Odin Ugedal <odin@uged.al>

[ Upstream commit 72d0ad7cb5bad265adb2014dbe46c4ccb11afaba ]

The time remaining until expiry of the refresh_timer can be negative.
Casting the type to an unsigned 64-bit value will cause integer
underflow, making the runtime_refresh_within return false instead of
true. These situations are rare, but they do happen.

This does not cause user-facing issues or errors; other than
possibly unthrottling cfs_rq's using runtime from the previous period(s),
making the CFS bandwidth enforcement less strict in those (special)
situations.

Signed-off-by: Odin Ugedal <odin@uged.al>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ben Segall <bsegall@google.com>
Link: https://lore.kernel.org/r/20210629121452.18429-1-odin@uged.al
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/sched/fair.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index acb34e9df551..6d3167e61e73 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4714,7 +4714,7 @@ static const u64 cfs_bandwidth_slack_period = 5 * NSEC_PER_MSEC;
 static int runtime_refresh_within(struct cfs_bandwidth *cfs_b, u64 min_expire)
 {
 	struct hrtimer *refresh_timer = &cfs_b->period_timer;
-	u64 remaining;
+	s64 remaining;
 
 	/* if the call-back is running a quota refresh is already occurring */
 	if (hrtimer_callback_running(refresh_timer))
@@ -4722,7 +4722,7 @@ static int runtime_refresh_within(struct cfs_bandwidth *cfs_b, u64 min_expire)
 
 	/* is a quota refresh about to occur? */
 	remaining = ktime_to_ns(hrtimer_expires_remaining(refresh_timer));
-	if (remaining < min_expire)
+	if (remaining < (s64)min_expire)
 		return 1;
 
 	return 0;
-- 
2.30.2


      parent reply	other threads:[~2021-07-14 20:00 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-14 19:45 [PATCH AUTOSEL 4.19 01/39] ARM: dts: gemini: rename mdio to the right name Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 4.19 02/39] ARM: dts: gemini: add device_type on pci Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 4.19 03/39] ARM: dts: rockchip: fix pinctrl sleep nodename for rk3036-kylin and rk3288 Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 4.19 04/39] arm64: dts: rockchip: fix pinctrl sleep nodename for rk3399.dtsi Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 4.19 05/39] ARM: dts: rockchip: Fix the timer clocks order Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 4.19 06/39] ARM: dts: rockchip: Fix IOMMU nodes properties on rk322x Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 4.19 07/39] ARM: dts: rockchip: Fix power-controller node names for rk3288 Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 4.19 08/39] arm64: dts: rockchip: Fix power-controller node names for rk3328 Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 4.19 09/39] reset: ti-syscon: fix to_ti_syscon_reset_data macro Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 4.19 10/39] ARM: brcmstb: dts: fix NAND nodes names Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 4.19 11/39] ARM: Cygnus: " Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 4.19 12/39] ARM: NSP: " Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 4.19 13/39] ARM: dts: BCM63xx: Fix " Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 4.19 14/39] ARM: dts: Hurricane 2: " Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 15/39] ARM: dts: imx25-pinfunc: Fix gpio function name for pads GPIO_[A-F] Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 16/39] ARM: dts: imx6: phyFLEX: Fix UART hardware flow control Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 17/39] ARM: imx: pm-imx5: Fix references to imx5_cpu_suspend_info Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 18/39] rtc: mxc_v2: add missing MODULE_DEVICE_TABLE Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 19/39] ARM: dts: am335x: align GPIO hog names with dt-schema Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 20/39] ARM: dts: am437x: align gpio " Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 21/39] ARM: dts: omap5-board-common: " Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 22/39] ARM: dts: dra7x-evm: Align GPIO " Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 23/39] ARM: dts: stm32: fix gpio-keys node on STM32 MCU boards Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 24/39] ARM: dts: stm32: fix RCC node name on stm32f429 MCU Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 25/39] ARM: dts: stm32: fix timer nodes on STM32 MCU to prevent warnings Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 26/39] arm64: dts: juno: Update SCPI nodes as per the YAML schema Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 27/39] ARM: dts: rockchip: fix supply properties in io-domains nodes Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 28/39] ARM: dts: stm32: fix i2c node name on stm32f746 to prevent warnings Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 29/39] ARM: dts: stm32: move stmmac axi config in ethernet node on stm32mp15 Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 30/39] soc/tegra: fuse: Fix Tegra234-only builds Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 31/39] arm64: dts: ls208xa: remove bus-num from dspi node Sasha Levin
2021-07-23 20:11   ` Pavel Machek
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 32/39] thermal/core: Correct function name thermal_zone_device_unregister() Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 33/39] kbuild: mkcompile_h: consider timestamp if KBUILD_BUILD_TIMESTAMP is set Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 34/39] rtc: max77686: Do not enforce (incorrect) interrupt trigger type Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 35/39] scsi: aic7xxx: Fix unintentional sign extension issue on left shift of u8 Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 36/39] scsi: libsas: Add LUN number check in .slave_alloc callback Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 37/39] scsi: be2iscsi: Fix some missing space in some messages Sasha Levin
2021-07-14 19:46 ` [PATCH AUTOSEL 4.19 38/39] scsi: libfc: Fix array index out of bound exception Sasha Levin
2021-07-14 19:46 ` Sasha Levin [this message]

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