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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 5.4 49/51] sched/fair: Fix CFS bandwidth hrtimer expiry type
Date: Wed, 14 Jul 2021 15:45:11 -0400	[thread overview]
Message-ID: <20210714194513.54827-49-sashal@kernel.org> (raw)
In-Reply-To: <20210714194513.54827-1-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 d3f4113e87de..94bf2e44a45a 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4786,7 +4786,7 @@ 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))
@@ -4794,7 +4794,7 @@ 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 19:58 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-14 19:44 [PATCH AUTOSEL 5.4 01/51] ARM: dts: gemini: rename mdio to the right name Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 02/51] ARM: dts: gemini: add device_type on pci Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 03/51] ARM: dts: rockchip: fix pinctrl sleep nodename for rk3036-kylin and rk3288 Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 04/51] arm64: dts: rockchip: fix pinctrl sleep nodename for rk3399.dtsi Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 05/51] ARM: dts: rockchip: Fix the timer clocks order Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 06/51] ARM: dts: rockchip: Fix IOMMU nodes properties on rk322x Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 07/51] ARM: dts: rockchip: Fix power-controller node names for rk3066a Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 08/51] ARM: dts: rockchip: Fix power-controller node names for rk3188 Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 09/51] ARM: dts: rockchip: Fix power-controller node names for rk3288 Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 10/51] arm64: dts: rockchip: Fix power-controller node names for px30 Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 11/51] arm64: dts: rockchip: Fix power-controller node names for rk3328 Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 12/51] reset: ti-syscon: fix to_ti_syscon_reset_data macro Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 13/51] ARM: brcmstb: dts: fix NAND nodes names Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 14/51] ARM: Cygnus: " Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 15/51] ARM: NSP: " Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 16/51] ARM: dts: BCM63xx: Fix " Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 17/51] ARM: dts: Hurricane 2: " Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 18/51] ARM: dts: imx25-pinfunc: Fix gpio function name for pads GPIO_[A-F] Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 19/51] ARM: dts: imx6: phyFLEX: Fix UART hardware flow control Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 20/51] ARM: imx: pm-imx5: Fix references to imx5_cpu_suspend_info Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 21/51] rtc: mxc_v2: add missing MODULE_DEVICE_TABLE Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 22/51] kbuild: sink stdout from cmd for silent build Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 23/51] ARM: dts: am335x: align GPIO hog names with dt-schema Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 24/51] ARM: dts: am437x: align gpio " Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 25/51] ARM: dts: omap3: " Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 26/51] ARM: dts: omap5-board-common: " Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 27/51] ARM: dts: dra7x-evm: Align GPIO " Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 28/51] ARM: dts: am57xx-cl-som-am57x: fix ti,no-reset-on-init flag for gpios Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 29/51] ARM: dts: am437x-gp-evm: " Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 30/51] ARM: dts: stm32: fix gpio-keys node on STM32 MCU boards Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 31/51] ARM: dts: stm32: fix RCC node name on stm32f429 MCU Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 32/51] ARM: dts: stm32: fix timer nodes on STM32 MCU to prevent warnings Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 33/51] arm64: dts: juno: Update SCPI nodes as per the YAML schema Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 34/51] ARM: dts: rockchip: fix supply properties in io-domains nodes Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 35/51] ARM: dts: stm32: fix i2c node name on stm32f746 to prevent warnings Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 36/51] ARM: dts: stm32: move stmmac axi config in ethernet node on stm32mp15 Sasha Levin
2021-07-14 19:44 ` [PATCH AUTOSEL 5.4 37/51] soc/tegra: fuse: Fix Tegra234-only builds Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 5.4 38/51] firmware: tegra: bpmp: " Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 5.4 39/51] arm64: dts: ls208xa: remove bus-num from dspi node Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 5.4 40/51] arm64: dts: imx8mq: assign PCIe clocks Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 5.4 41/51] thermal/core: Correct function name thermal_zone_device_unregister() Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 5.4 42/51] kbuild: mkcompile_h: consider timestamp if KBUILD_BUILD_TIMESTAMP is set Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 5.4 43/51] rtc: max77686: Do not enforce (incorrect) interrupt trigger type Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 5.4 44/51] scsi: aic7xxx: Fix unintentional sign extension issue on left shift of u8 Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 5.4 45/51] scsi: libsas: Add LUN number check in .slave_alloc callback Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 5.4 46/51] scsi: be2iscsi: Fix some missing space in some messages Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 5.4 47/51] scsi: libfc: Fix array index out of bound exception Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 5.4 48/51] scsi: qedf: Add check to synchronize abort and flush Sasha Levin
2021-07-14 19:45 ` Sasha Levin [this message]
2021-07-14 19:45 ` [PATCH AUTOSEL 5.4 50/51] s390: introduce proper type handling call_on_stack() macro Sasha Levin
2021-07-14 19:45 ` [PATCH AUTOSEL 5.4 51/51] cifs: prevent NULL deref in cifs_compose_mount_options() Sasha Levin

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