Hi Yasuaki,
On Wed, Jul 23, 2014 at 05:56:07PM +0900, Yasuaki Ishimatsu wrote:
(2014/07/22 17:04), Wanpeng Li wrote:
[ 220.262093] BUG: unable to handle kernel NULL pointer dereference at 0000000000000004
[ 220.262104] IP: [<ffffffff810e7ac9>] find_busiest_group+0x2b9/0xa30
[ 220.262111] PGD 5a9d5067 PUD 13067 PMD 0
[ 220.262117] Oops: 0000 [#3] SMP
[...]
[ 220.262245] Call Trace:
[ 220.262252] [<ffffffff810e8396>] load_balance+0x156/0x980
[ 220.262259] [<ffffffff816eeffe>] ? _raw_spin_unlock_irqrestore+0x2e/0xa0
[ 220.262266] [<ffffffff810e9aa3>] idle_balance+0xe3/0x150
[ 220.262270] [<ffffffff816ec4e7>] __schedule+0x797/0x8d0
[ 220.262277] [<ffffffff816ec934>] schedule+0x24/0x70
[ 220.262283] [<ffffffff816e9cd9>] schedule_timeout+0x119/0x1f0
[ 220.262294] [<ffffffff810bb6e0>] ? lock_timer_base+0x70/0x70
[ 220.262301] [<ffffffff816e9dc9>] schedule_timeout_uninterruptible+0x19/0x20
[ 220.262308] [<ffffffff810bd3e8>] msleep+0x18/0x20
[ 220.262317] [<ffffffff813aa11a>] lock_device_hotplug_sysfs+0x2a/0x50
[ 220.262323] [<ffffffff813aa16e>] online_store+0x2e/0x80
[ 220.262358] [<ffffffff813a873b>] dev_attr_store+0x1b/0x20
[ 220.262366] [<ffffffff812292fd>] sysfs_write_file+0xdd/0x160
[ 220.262377] [<ffffffff811b7e78>] vfs_write+0xc8/0x170
[ 220.262384] [<ffffffff811b83ca>] SyS_write+0x5a/0xa0
[ 220.262388] [<ffffffff816f76b9>] system_call_fastpath+0x16/0x1b
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.
I posted a latest patch as follows:
https://lkml.org/lkml/2014/7/22/1018
Could you confirm the patch fixes your issue?
Sorry for the late, there is still call trace w/ your patch applied. The
call trace is in attachment.
Regards,
Wanpeng Li
Thanks,
Yasuaki Ishimatsu
Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxxxxxx>
---
v1 -> v2:
* fix subject line
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;