From: Borislav Petkov <bp@alien8.de>
To: Wanpeng Li <wanpeng.li@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>,
hpa@zytor.com, Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
x86@kernel.org,
Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>,
David Rientjes <rientjes@google.com>,
Prarit Bhargava <prarit@redhat.com>,
Steven Rostedt <srostedt@redhat.com>,
Toshi Kani <toshi.kani@hp.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5] x86, cpu-hotplug: fix llc shared map unreleased during cpu hotplug
Date: Tue, 23 Sep 2014 11:37:53 +0200 [thread overview]
Message-ID: <20140923093753.GA22644@pd.tnic> (raw)
In-Reply-To: <1410938272-7217-1-git-send-email-wanpeng.li@linux.intel.com>
On Wed, Sep 17, 2014 at 03:17:52PM +0800, Wanpeng Li wrote:
> BUG: unable to handle kernel NULL pointer dereference at 0000000000000004
> IP: [..] find_busiest_group
> PGD 5a9d5067 PUD 13067 PMD 0
> Oops: 0000 [#3] SMP
> [...]
> Call Trace:
> load_balance
> ? _raw_spin_unlock_irqrestore
> idle_balance
> __schedule
> schedule
> schedule_timeout
> ? lock_timer_base
> schedule_timeout_uninterruptible
> msleep
> lock_device_hotplug_sysfs
> online_store
> dev_attr_store
> sysfs_write_file
> vfs_write
> SyS_write
> system_call_fastpath
>
> This bug can be triggered by hot add and remove large number of xen
> domain0's vcpus repeatedly.
>
> Last level cache shared map is built during cpu up and build sched domain
> routine takes advantage of it to setup sched domain cpu topology, however,
> llc shared map is unreleased during cpu disable which lead to invalid sched
> domain cpu topology. This patch fix it by release llc shared map correctly
> during cpu disable.
>
> Reviewed-by: Toshi Kani <toshi.kani@hp.com>
> Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
> Tested-by: Linn Crosetto <linn@hp.com>
> Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
--
Regards/Gruss,
Boris.
Sent from a fat crate under my desk. Formatting is fine.
--
next prev parent reply other threads:[~2014-09-23 9:38 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-17 7:17 Wanpeng Li
2014-09-21 23:11 ` Wanpeng Li
2014-09-23 4:46 ` Kamezawa Hiroyuki
2014-09-23 6:36 ` Wanpeng Li
2014-09-23 7:56 ` Kamezawa Hiroyuki
2014-09-23 9:37 ` Borislav Petkov [this message]
2014-09-23 23:48 ` Wanpeng Li
2014-09-24 7:52 ` Ingo Molnar
2014-09-24 8:18 ` Wanpeng Li
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