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From: Tang Chen <tangchen@cn.fujitsu.com>
To: peterz@infradead.org, srivatsa.bhat@linux.vnet.ibm.com,
	mingo@kernel.org, tglx@linutronix.de,
	linux-kernel@vger.kernel.org, x86@kernel.org,
	linux-numa@vger.kernel.org
Subject: [PATCH v2 0/2] Update sched_domains_numa_masks when new cpus are onlined.
Date: Tue, 25 Sep 2012 21:12:29 +0800	[thread overview]
Message-ID: <1348578751-16904-1-git-send-email-tangchen@cn.fujitsu.com> (raw)

Once array sched_domains_numa_masks is defined, it is never updated.
When a new cpu on a new node is onlined, the coincident member in
sched_domains_numa_masks is not initialized, and all the masks are 0.
As a result, the build_overlap_sched_groups() will initialize a NULL
sched_group for the new cpu on the new node, which will lead to kernel panic.

[ 3189.403280] Call Trace:
[ 3189.403286]  [<ffffffff8106c36f>] warn_slowpath_common+0x7f/0xc0
[ 3189.403289]  [<ffffffff8106c3ca>] warn_slowpath_null+0x1a/0x20
[ 3189.403292]  [<ffffffff810b1d57>] build_sched_domains+0x467/0x470
[ 3189.403296]  [<ffffffff810b2067>] partition_sched_domains+0x307/0x510
[ 3189.403299]  [<ffffffff810b1ea2>] ? partition_sched_domains+0x142/0x510
[ 3189.403305]  [<ffffffff810fcc93>] cpuset_update_active_cpus+0x83/0x90
[ 3189.403308]  [<ffffffff810b22a8>] cpuset_cpu_active+0x38/0x70
[ 3189.403316]  [<ffffffff81674b87>] notifier_call_chain+0x67/0x150
[ 3189.403320]  [<ffffffff81664647>] ? native_cpu_up+0x18a/0x1b5
[ 3189.403328]  [<ffffffff810a044e>] __raw_notifier_call_chain+0xe/0x10
[ 3189.403333]  [<ffffffff81070470>] __cpu_notify+0x20/0x40
[ 3189.403337]  [<ffffffff8166663e>] _cpu_up+0xe9/0x131
[ 3189.403340]  [<ffffffff81666761>] cpu_up+0xdb/0xee
[ 3189.403348]  [<ffffffff8165667c>] store_online+0x9c/0xd0
[ 3189.403355]  [<ffffffff81437640>] dev_attr_store+0x20/0x30
[ 3189.403361]  [<ffffffff8124aa63>] sysfs_write_file+0xa3/0x100
[ 3189.403368]  [<ffffffff811ccbe0>] vfs_write+0xd0/0x1a0
[ 3189.403371]  [<ffffffff811ccdb4>] sys_write+0x54/0xa0
[ 3189.403375]  [<ffffffff81679c69>] system_call_fastpath+0x16/0x1b
[ 3189.403377] ---[ end trace 1e6cf85d0859c941 ]---
[ 3189.403398] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018

This patch registers a new notifier for cpu hotplug notify chain, and
updates sched_domains_numa_masks every time a new cpu is onlined or offlined.


Tang Chen (2):
  Ensure sched_domains_numa_levels safe in other functions.
  Update sched_domains_numa_masks when new cpus are onlined.

 kernel/sched/core.c |   69 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)

-- 
1.7.10.1


             reply	other threads:[~2012-09-25 13:10 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-25 13:12 Tang Chen [this message]
2012-09-25 13:12 ` [PATCH v2 1/2] Ensure sched_domains_numa_levels safe in other functions Tang Chen
2012-10-05 13:01   ` [tip:sched/urgent] sched: Ensure 'sched_domains_numa_levels' is safe to use " tip-bot for Tang Chen
2012-09-25 13:12 ` [PATCH v2 2/2] Update sched_domains_numa_masks when new cpus are onlined Tang Chen
2012-10-04 12:30   ` Peter Zijlstra
2012-10-05 13:02   ` [tip:sched/urgent] sched: Update sched_domains_numa_masks[][] " tip-bot for Tang Chen
2012-10-02 11:33 ` [PATCH v2 0/2] Update sched_domains_numa_masks " Peter Zijlstra

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