From: Sasha Levin <sashal@kernel.org>
To: stable@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Valentin Schneider <valentin.schneider@arm.com>,
Peter Zijlstra <peterz@infradead.org>,
Dietmar.Eggemann@arm.com,
Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
morten.rasmussen@arm.com, quentin.perret@arm.com,
Ingo Molnar <mingo@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 4.18 40/59] sched/core: Take the hotplug lock in sched_init_smp()
Date: Wed, 14 Nov 2018 17:23:12 -0500 [thread overview]
Message-ID: <20181114222335.99339-40-sashal@kernel.org> (raw)
In-Reply-To: <20181114222335.99339-1-sashal@kernel.org>
From: Valentin Schneider <valentin.schneider@arm.com>
[ Upstream commit 40fa3780bac2b654edf23f6b13f4e2dd550aea10 ]
When running on linux-next (8c60c36d0b8c ("Add linux-next specific files
for 20181019")) + CONFIG_PROVE_LOCKING=y on a big.LITTLE system (e.g.
Juno or HiKey960), we get the following report:
[ 0.748225] Call trace:
[ 0.750685] lockdep_assert_cpus_held+0x30/0x40
[ 0.755236] static_key_enable_cpuslocked+0x20/0xc8
[ 0.760137] build_sched_domains+0x1034/0x1108
[ 0.764601] sched_init_domains+0x68/0x90
[ 0.768628] sched_init_smp+0x30/0x80
[ 0.772309] kernel_init_freeable+0x278/0x51c
[ 0.776685] kernel_init+0x10/0x108
[ 0.780190] ret_from_fork+0x10/0x18
The static_key in question is 'sched_asym_cpucapacity' introduced by
commit:
df054e8445a4 ("sched/topology: Add static_key for asymmetric CPU capacity optimizations")
In this particular case, we enable it because smp_prepare_cpus() will
end up fetching the capacity-dmips-mhz entry from the devicetree,
so we already have some asymmetry detected when entering sched_init_smp().
This didn't get detected in tip/sched/core because we were missing:
commit cb538267ea1e ("jump_label/lockdep: Assert we hold the hotplug lock for _cpuslocked() operations")
Calls to build_sched_domains() post sched_init_smp() will hold the
hotplug lock, it just so happens that this very first call is a
special case. As stated by a comment in sched_init_smp(), "There's no
userspace yet to cause hotplug operations" so this is a harmless
warning.
However, to both respect the semantics of underlying
callees and make lockdep happy, take the hotplug lock in
sched_init_smp(). This also satisfies the comment atop
sched_init_domains() that says "Callers must hold the hotplug lock".
Reported-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dietmar.Eggemann@arm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: morten.rasmussen@arm.com
Cc: quentin.perret@arm.com
Link: http://lkml.kernel.org/r/1540301851-3048-1-git-send-email-valentin.schneider@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/sched/core.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5ba96d9ddbde..8f16f3c8672a 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5890,11 +5890,14 @@ void __init sched_init_smp(void)
/*
* There's no userspace yet to cause hotplug operations; hence all the
* CPU masks are stable and all blatant races in the below code cannot
- * happen.
+ * happen. The hotplug lock is nevertheless taken to satisfy lockdep,
+ * but there won't be any contention on it.
*/
+ cpus_read_lock();
mutex_lock(&sched_domains_mutex);
sched_init_domains(cpu_active_mask);
mutex_unlock(&sched_domains_mutex);
+ cpus_read_unlock();
/* Move init over to a non-isolated CPU */
if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_FLAG_DOMAIN)) < 0)
--
2.17.1
next prev parent reply other threads:[~2018-11-14 22:24 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-14 22:22 [PATCH AUTOSEL 4.18 01/59] s390/vdso: add missing FORCE to build targets Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 02/59] HID: i2c-hid: Add a small delay after sleep command for Raydium touchpanel Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 03/59] Revert "HID: add NOGET quirk for Eaton Ellipse MAX UPS" Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 04/59] HID: alps: allow incoming reports when only the trackstick is opened Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 05/59] netfilter: ipset: list:set: Decrease refcount synchronously on deletion and replace Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 06/59] netfilter: ipset: actually allow allowable CIDR 0 in hash:net,port,net Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 07/59] netfilter: ipset: fix ip_set_list allocation failure Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 08/59] s390/mm: fix mis-accounting of pgtable_bytes Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 09/59] s390/mm: Fix ERROR: "__node_distance" undefined! Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 10/59] bpf: fix bpf_prog_get_info_by_fd to return 0 func_lens for unpriv Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 11/59] usbnet: smsc95xx: disable carrier check while suspending Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 12/59] net: dsa: microchip: initialize mutex before use Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 13/59] net: bcmgenet: protect stop from timeout Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 14/59] net: systemport: Protect " Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 15/59] netfilter: ipset: Correct rcu_dereference() call in ip_set_put_comment() Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 16/59] netfilter: xt_IDLETIMER: add sysfs filename checking routine Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 17/59] netfilter: ipset: Fix calling ip_set() macro at dumping Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 18/59] netfilter: nft_compat: ebtables 'nat' table is normal chain type Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 19/59] s390/qeth: fix HiperSockets sniffer Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 20/59] net: hns3: Fix for out-of-bounds access when setting pfc back pressure Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 21/59] mlxsw: spectrum: Fix IP2ME CPU policer configuration Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 22/59] hwmon: (ibmpowernv) Remove bogus __init annotations Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 23/59] net: phy: realtek: fix RTL8201F sysfs name Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 24/59] ARM: dts: fsl: Fix improperly quoted stdout-path values Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 25/59] ARM: dts: imx6sx-sdb: Fix enet phy regulator Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 26/59] Revert "drm/exynos/decon5433: implement frame counter" Sasha Levin
2018-11-14 22:22 ` [PATCH AUTOSEL 4.18 27/59] arm64: dts: renesas: r8a7795: add missing dma-names on hscif2 Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 28/59] clk: fixed-factor: fix of_node_get-put imbalance Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 29/59] mtd: nand: Fix nanddev_pos_next_page() kernel-doc header Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 30/59] lib/raid6: Fix arm64 test build Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 31/59] drm/amd/display: Stop leaking planes Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 32/59] block: Clear kernel memory before copying to user Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 33/59] drm/amd/amdgpu/dm: Fix dm_dp_create_fake_mst_encoder() Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 34/59] s390/perf: Change CPUM_CF return code in event init function Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 35/59] ceph: quota: fix null pointer dereference in quota check Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 36/59] clk: meson-gxbb: set fclk_div3 as CLK_IS_CRITICAL Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 37/59] clk: meson: axg: mark fdiv2 and fdiv3 as critical Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 38/59] nvme: make sure ns head inherits underlying device limits Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 39/59] i2c: omap: Enable for ARCH_K3 Sasha Levin
2018-11-15 4:35 ` Vignesh R
2018-11-22 19:31 ` Sasha Levin
2018-11-14 22:23 ` Sasha Levin [this message]
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 41/59] perf tools: Fix undefined symbol scnprintf in libperf-jvmti.so Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 42/59] perf tools: Do not zero sample_id_all for group members Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 43/59] ice: Fix dead device link issue with flow control Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 44/59] ice: Fix the bytecount sent to netdev_tx_sent_queue Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 45/59] i40e: restore NETIF_F_GSO_IPXIP[46] to netdev features Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 46/59] ibmvnic: fix accelerated VLAN handling Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 47/59] qed: Fix memory/entry leak in qed_init_sp_request() Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 48/59] qed: Fix blocking/unlimited SPQ entries leak Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 49/59] qed: Fix SPQ entries not returned to pool in error flows Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 50/59] qed: Fix potential memory corruption Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 51/59] net: stmmac: Fix RX packet size > 8191 Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 52/59] net: smsc95xx: Fix MTU range Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 53/59] ext4: missing !bh check in ext4_xattr_inode_write() Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 54/59] net: aquantia: fix potential IOMMU fault after driver unbind Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 55/59] net: aquantia: fixed enable unicast on 32 macvlan Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 56/59] net: aquantia: invalid checksumm offload implementation Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 57/59] net: qualcomm: rmnet: Fix incorrect assignment of real_dev Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 58/59] kbuild: deb-pkg: fix too low build version number Sasha Levin
2018-11-14 22:23 ` [PATCH AUTOSEL 4.18 59/59] net: dsa: mv88e6xxx: Fix clearing of stats counters Sasha Levin
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