From: Dario Faggioli <dario.faggioli@citrix.com>
To: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: Wei Wang <wei.w.wang@intel.com>, Jan Beulich <JBeulich@suse.com>
Subject: patch "x86/cpufreq: relocate the driver register function" breaks cpu hot(un)plug
Date: Fri, 9 Oct 2015 18:48:23 +0200 [thread overview]
Message-ID: <1444409303.3009.5.camel@citrix.com> (raw)
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Hey,
As far as my bisection goes, commit
49388f11d512bb92706ce046643bfbb3c1d963c9 "x86/cpufreq: relocate the
driver register function" prevents me from hot unplugging pCPUs.
Xen does not crash or anything, but dom0 is stalled. In fact, with
current staging, here's what I see:
root@Zhaman:~# echo 0 > /sys/devices/system/xen_cpu/xen_cpu6/online
[ 81.583001] INFO: rcu_sched detected stalls on CPUs/tasks: { 12} (detected by 3, t=5252 jiffies, g=1691, c=1690, q=76)
[ 81.583036] Task dump for CPU 12:
[ 81.583044] bash R running task 0 1347 1094 0x00000008
[ 81.583056] ffffffff00000000 0000000000000000 0000000000000000 ffff8800192c2e38
[ 81.583070] ffff8800008472e8 0000000000000002 ffff8800008472e8 ffff880013817858
[ 81.583082] 0000000000000000 00000000000081a4 ffffffff811e8137 ffff8800192c2e38
[ 81.583095] Call Trace:
[ 81.583110] [<ffffffff811e8137>] ? notify_change+0x2f7/0x390
[ 81.583148] [<ffffffff811c8c74>] ? do_truncate+0x74/0x90
[ 81.583158] [<ffffffff811e2866>] ? dput+0x26/0x230
[ 81.583167] [<ffffffff811d53c5>] ? terminate_walk+0x35/0x40
[ 81.583176] [<ffffffff811d92b1>] ? do_last+0x621/0x12c0
[ 81.583188] [<ffffffff8139f0e7>] ? xen_pcpu_down+0x47/0x70
[ 81.583199] [<ffffffff8156c64d>] ? store_online+0x9d/0xb0
[ 81.583210] [<ffffffff81240bfc>] ? kernfs_fop_write+0x12c/0x180
[ 81.583220] [<ffffffff811ca513>] ? __vfs_write+0x23/0xf0
[ 81.583230] [<ffffffff811cd142>] ? __sb_start_write+0x42/0xf0
[ 81.583241] [<ffffffff8125f711>] ? security_file_permission+0x21/0xa0
[ 81.583250] [<ffffffff811caea1>] ? vfs_write+0xa1/0x1c0
[ 81.583259] [<ffffffff811c828f>] ? filp_close+0x4f/0x70
[ 81.583268] [<ffffffff811cbb12>] ? SyS_write+0x42/0xb0
[ 81.583277] [<ffffffff811e9031>] ? __close_fd+0x71/0xb0
[ 81.583287] [<ffffffff815780f2>] ? system_call_fastpath+0x16/0x75
[ 144.555020] INFO: rcu_sched detected stalls on CPUs/tasks: { 12} (detected by 4, t=21007 jiffies, g=1691, c=1690, q=244)
[ 144.555046] Task dump for CPU 12:
[ 144.555051] bash R running task 0 1347 1094 0x00000008
[ 144.555059] ffffffff00000000 0000000000000000 0000000000000000 ffff8800192c2e38
[ 144.555068] ffff8800008472e8 0000000000000002 ffff8800008472e8 ffff880013817858
[ 144.555076] 0000000000000000 00000000000081a4 ffffffff811e8137 ffff8800192c2e38
[ 144.555084] Call Trace:
[ 144.555096] [<ffffffff811e8137>] ? notify_change+0x2f7/0x390
[ 144.555105] [<ffffffff811c8c74>] ? do_truncate+0x74/0x90
[ 144.555112] [<ffffffff811e2866>] ? dput+0x26/0x230
[ 144.555118] [<ffffffff811d53c5>] ? terminate_walk+0x35/0x40
[ 144.555124] [<ffffffff811d92b1>] ? do_last+0x621/0x12c0
[ 144.555164] [<ffffffff8139f0e7>] ? xen_pcpu_down+0x47/0x70
[ 144.555172] [<ffffffff8156c64d>] ? store_online+0x9d/0xb0
[ 144.555179] [<ffffffff81240bfc>] ? kernfs_fop_write+0x12c/0x180
[ 144.555186] [<ffffffff811ca513>] ? __vfs_write+0x23/0xf0
[ 144.555192] [<ffffffff811cd142>] ? __sb_start_write+0x42/0xf0
[ 144.555200] [<ffffffff8125f711>] ? security_file_permission+0x21/0xa0
[ 144.555206] [<ffffffff811caea1>] ? vfs_write+0xa1/0x1c0
[ 144.555212] [<ffffffff811c828f>] ? filp_close+0x4f/0x70
[ 144.555217] [<ffffffff811cbb12>] ? SyS_write+0x42/0xb0
[ 144.555223] [<ffffffff811e9031>] ? __close_fd+0x71/0xb0
[ 144.555230] [<ffffffff815780f2>] ? system_call_fastpath+0x16/0x75
If I revert that patch, the issue goes away.
Any ideas?
Regards,
Dario
PS. yes, I'll implement a cpu hotplug/unplug testcase ASAP. :-)
--
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)
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next reply other threads:[~2015-10-09 16:48 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-09 16:48 Dario Faggioli [this message]
2015-10-09 20:00 ` patch "x86/cpufreq: relocate the driver register function" breaks cpu hot(un)plug Konrad Rzeszutek Wilk
2015-10-10 1:38 ` Wang, Wei W
2015-10-12 13:22 ` Jan Beulich
2015-10-12 13:34 ` Dario Faggioli
2015-10-12 13:19 ` Jan Beulich
2015-10-12 13:22 ` Dario Faggioli
2015-10-12 13:25 ` Andrew Cooper
2015-10-12 13:29 ` Jan Beulich
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