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* [PATCH v4] x86, hotplug: fix llc shared map unreleased during cpu hotplug
@ 2014-07-29  9:24 Wanpeng Li
  2014-07-29 17:18 ` Toshi Kani
                   ` (3 more replies)
  0 siblings, 4 replies; 16+ messages in thread
From: Wanpeng Li @ 2014-07-29  9:24 UTC (permalink / raw)
  To: hpa
  Cc: Ingo Molnar, Peter Zijlstra, x86, Borislav Petkov,
	Yasuaki Ishimatsu, David Rientjes, Prarit Bhargava,
	Steven Rostedt, Jan Kiszka, Toshi Kani, linux-kernel, Zhang Yang,
	Konrad Rzeszutek Wilk, Wanpeng Li

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

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: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
---
v1 -> v2:
 * fix subject line
v2 -> v3:
 * simplify backtrace 

 arch/x86/kernel/smpboot.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 5492798..0134ec7 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1292,6 +1292,9 @@ static void remove_siblinginfo(int cpu)
 
 	for_each_cpu(sibling, cpu_sibling_mask(cpu))
 		cpumask_clear_cpu(cpu, cpu_sibling_mask(sibling));
+	for_each_cpu(sibling, cpu_llc_shared_mask(cpu))
+		cpumask_clear_cpu(cpu, cpu_llc_shared_mask(sibling));
+	cpumask_clear(cpu_llc_shared_mask(cpu));
 	cpumask_clear(cpu_sibling_mask(cpu));
 	cpumask_clear(cpu_core_mask(cpu));
 	c->phys_proc_id = 0;
-- 
1.9.1


^ permalink raw reply related	[flat|nested] 16+ messages in thread

end of thread, other threads:[~2014-09-16 10:00 UTC | newest]

Thread overview: 16+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-07-29  9:24 [PATCH v4] x86, hotplug: fix llc shared map unreleased during cpu hotplug Wanpeng Li
2014-07-29 17:18 ` Toshi Kani
2014-08-07  6:33 ` Wanpeng Li
     [not found] ` <20140808224057.GA9288@oranje.fc.hp.com>
2014-08-15  3:00   ` Wanpeng Li
2014-08-15  6:07     ` Borislav Petkov
2014-08-25  5:32       ` Wanpeng Li
2014-09-04  1:46         ` Wanpeng Li
2014-09-04  5:20 ` Ingo Molnar
2014-09-04  5:40   ` Yasuaki Ishimatsu
2014-09-04  6:24     ` Peter Zijlstra
2014-09-04  9:02     ` Wanpeng Li
2014-09-04  8:56   ` Wanpeng Li
2014-09-04  9:34     ` Wanpeng Li
2014-09-15  1:32       ` Wanpeng Li
2014-09-16  9:01       ` Ingo Molnar
2014-09-16 10:00         ` Wanpeng Li

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