From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: "Michal Koutný" <mkoutny@suse.com>
Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org,
Zhao Gongyi <zhaogongyi@huawei.com>,
Zhang Qiao <zhangqiao22@huawei.com>,
Waiman Long <longman@redhat.com>, Tejun Heo <tj@kernel.org>,
Juri Lelli <juri.lelli@redhat.com>
Subject: Re: [PATCH 4.19 01/34] cgroup/cpuset: Fix a race between cpuset_attach() and cpu hotplug
Date: Mon, 14 Mar 2022 09:06:12 +0100 [thread overview]
Message-ID: <Yi73dKB10LBTGb+S@kroah.com> (raw)
In-Reply-To: <20220308151232.GA21752@blackbody.suse.cz>
On Tue, Mar 08, 2022 at 04:12:32PM +0100, Michal Koutný wrote:
> Hello.
>
> On Mon, Feb 28, 2022 at 06:24:07PM +0100, Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
> > [...]
> > cpuset_attach() cpu hotplug
> > --------------------------- ----------------------
> > down_write(cpuset_rwsem)
> > guarantee_online_cpus() // (load cpus_attach)
> > sched_cpu_deactivate
> > set_cpu_active()
> > // will change cpu_active_mask
> > set_cpus_allowed_ptr(cpus_attach)
> > __set_cpus_allowed_ptr_locked()
> > // (if the intersection of cpus_attach and
> > cpu_active_mask is empty, will return -EINVAL)
> > up_write(cpuset_rwsem)
> > [...]
> > --- a/kernel/cgroup/cpuset.c
> > +++ b/kernel/cgroup/cpuset.c
> > @@ -1528,6 +1528,7 @@ static void cpuset_attach(struct cgroup_
> > cgroup_taskset_first(tset, &css);
> > cs = css_cs(css);
> >
> > + cpus_read_lock();
> > mutex_lock(&cpuset_mutex);
>
> This backport (and possible older kernels) looks suspicious since it comes
> before commit d74b27d63a8b ("cgroup/cpuset: Change cpuset_rwsem and
> hotplug lock order") v5.4-rc1~176^2~30 when the locking order was:
> cpuset lock, cpus lock.
>
> At the same time it also comes before commit 710da3c8ea7d ("sched/core:
> Prevent race condition between cpuset and __sched_setscheduler()")
> v5.4-rc1~176^2~27 when neither __sched_setscheduler() cared and this
> race is similar. (The swapped locking may still conflict with
> rebuild_sched_domains() before d74b27d63a8b.)
Thanks for noticing this. What do you recommend to do to resolve this?
thanks,
greg k-h
next prev parent reply other threads:[~2022-03-14 8:07 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-28 17:24 [PATCH 4.19 00/34] 4.19.232-rc1 review Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 01/34] cgroup/cpuset: Fix a race between cpuset_attach() and cpu hotplug Greg Kroah-Hartman
2022-03-08 15:12 ` Michal Koutný
2022-03-14 8:06 ` Greg Kroah-Hartman [this message]
2022-03-14 9:11 ` Zhang Qiao
2022-03-14 11:19 ` Michal Koutný
2022-03-16 14:27 ` Greg Kroah-Hartman
2022-03-17 2:41 ` Zhang Qiao
2022-03-17 10:24 ` Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 02/34] vhost/vsock: dont check owner in vhost_vsock_stop() while releasing Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 03/34] parisc/unaligned: Fix fldd and fstd unaligned handlers on 32-bit kernel Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 04/34] parisc/unaligned: Fix ldw() and stw() unalignment handlers Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 05/34] sr9700: sanity check for packet length Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 06/34] USB: zaurus: support another broken Zaurus Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 07/34] ping: remove pr_err from ping_lookup Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 08/34] net: __pskb_pull_tail() & pskb_carve_frag_list() drop_monitor friends Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 09/34] tipc: Fix end of loop tests for list_for_each_entry() Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 10/34] gso: do not skip outer ip header in case of ipip and net_failover Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 11/34] openvswitch: Fix setting ipv6 fields causing hw csum failure Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 12/34] drm/edid: Always set RGB444 Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 13/34] net/mlx5e: Fix wrong return value on ioctl EEPROM query failure Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 14/34] configfs: fix a race in configfs_{,un}register_subsystem() Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 15/34] RDMA/ib_srp: Fix a deadlock Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 16/34] tty: n_gsm: fix proper link termination after failed open Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 17/34] gpio: tegra186: Fix chip_data type confusion Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 18/34] Revert "drm/nouveau/pmu/gm200-: avoid touching PMU outside of DEVINIT/PREOS/ACR" Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 19/34] memblock: use kfree() to release kmalloced memblock regions Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 20/34] fget: clarify and improve __fget_files() implementation Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 21/34] tracing: Have traceon and traceoff trigger honor the instance Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 22/34] iio: adc: men_z188_adc: Fix a resource leak in an error handling path Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 23/34] ata: pata_hpt37x: disable primary channel on HPT371 Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 24/34] Revert "USB: serial: ch341: add new Product ID for CH341A" Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 25/34] usb: gadget: rndis: add spinlock for rndis response list Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 26/34] USB: gadget: validate endpoint index for xilinx udc Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 27/34] tracefs: Set the group ownership in apply_options() not parse_options() Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 28/34] USB: serial: option: add support for DW5829e Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 29/34] USB: serial: option: add Telit LE910R1 compositions Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 30/34] usb: dwc3: pci: Fix Bay Trail phy GPIO mappings Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 31/34] usb: dwc3: gadget: Let the interrupt handler disable bottom halves Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 32/34] xhci: re-initialize the HC during resume if HCE was set Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 33/34] xhci: Prevent futile URB re-submissions due to incorrect return value Greg Kroah-Hartman
2022-02-28 17:24 ` [PATCH 4.19 34/34] tty: n_gsm: fix encoding of control signal octet bit DV Greg Kroah-Hartman
2022-02-28 21:21 ` [PATCH 4.19 00/34] 4.19.232-rc1 review Pavel Machek
2022-02-28 21:42 ` Shuah Khan
2022-03-01 11:32 ` Sudip Mukherjee
2022-03-01 16:37 ` Naresh Kamboju
2022-03-01 18:23 ` Jeffrin Thalakkottoor
2022-03-01 19:10 ` Guenter Roeck
2022-03-01 19:36 ` Slade Watkins
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