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Message-ID: <5abac4eb.VlEjF4GlZAlHJzXX%fengguang.wu@intel.com>
Date: Wed, 28 Mar 2018 06:25:47 +0800
From: kernel test robot <fengguang.wu@...el.com>
To: Eric Dumazet <edumazet@...gle.com>
Cc: LKP <lkp@...org>, linux-kernel@...r.kernel.org,
Thomas Gleixner <tglx@...utronix.de>, wfg@...ux.intel.com
Subject: 07cde313b2 ("x86/msr: Allow rdmsr_safe_on_cpu() to schedule"):
BUG: kernel hang in boot stage
Greetings,
0day kernel testing robot got the below dmesg and the first bad commit is
https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/cleanups
commit 07cde313b2d21f728cec2836db7cdb55476f7a26
Author: Eric Dumazet <edumazet@...gle.com>
AuthorDate: Fri Mar 23 14:58:17 2018 -0700
Commit: Thomas Gleixner <tglx@...utronix.de>
CommitDate: Tue Mar 27 12:01:47 2018 +0200
x86/msr: Allow rdmsr_safe_on_cpu() to schedule
High latencies can be observed caused by a daemon periodically reading
various MSR on all cpus. On KASAN enabled kernels ~10ms latencies can be
observed simply reading one MSR. Even without KASAN, sending an IPI to a
CPU, which is in a deep sleep state or in a long hard IRQ disabled section,
waiting for the answer can consume hundreds of microseconds.
All usage sites are in preemptible context, convert rdmsr_safe_on_cpu() to
use a completion instead of busy polling.
Overall daemon cpu usage was reduced by 35 %, and latencies caused by
msr_read() disappeared.
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Acked-by: Ingo Molnar <mingo@...nel.org>
Cc: Hugh Dickins <hughd@...gle.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Eric Dumazet <eric.dumazet@...il.com>
Link: https://lkml.kernel.org/r/20180323215818.127774-1-edumazet@google.com
13cc36d76b x86/rtc: Stop using deprecated functions
07cde313b2 x86/msr: Allow rdmsr_safe_on_cpu() to schedule
67bbd7a8d6 x86/cpuid: Allow cpuid_read() to schedule
990d052537 Merge branch 'x86/mm'
+-------------------------------+------------+------------+------------+------------+
| | 13cc36d76b | 07cde313b2 | 67bbd7a8d6 | 990d052537 |
+-------------------------------+------------+------------+------------+------------+
| boot_successes | 33 | 4 | 2 | 4 |
| boot_failures | 0 | 11 | 15 | 11 |
| BUG:kernel_hang_in_boot_stage | 0 | 11 | 13 | 11 |
| BUG:kernel_in_stage | 0 | 0 | 2 | |
+-------------------------------+------------+------------+------------+------------+
[ 14.950320] fmc_trivial: probe of fake-design-for-testing-f001 failed with error -95
[ 14.953048] fmc fake-design-for-testing-f001: Driver has no ID: matches all
[ 14.955084] fmc_write_eeprom fake-design-for-testing-f001: fmc_write_eeprom: no busid passed, refusing all cards
[ 14.958301] fmc fake-design-for-testing-f001: Driver has no ID: matches all
[ 14.960428] fmc_chardev fake-design-for-testing-f001: Created misc device "fake-design-for-testing-f001"
BUG: kernel hang in boot stage
# HH:MM RESULT GOOD BAD GOOD_BUT_DIRTY DIRTY_NOT_BAD
git bisect start c98e6b78ee92a4c5662febce64591980d77bd6c6 3eb2ce825ea1ad89d20f7a3b5780df850e4be274 --
git bisect bad 110c6c42e12d406bf2e5c15e71023ed2e91cb17d # 01:31 B 0 11 24 0 Merge 'linux-review/Alex-Williamson/MAINTAINERS-vfio-platform-Update-sub-maintainer/20180327-143800' into devel-spot-201803272204
git bisect good ec45958cf484f5c9310df39d9f85dd43c22ae799 # 01:47 G 11 0 2 2 Merge 'slave-dma/next' into devel-spot-201803272204
git bisect good 7103b9adcdc2a848c54f3afa4ab7730f420f3fe0 # 02:18 G 11 0 1 1 Merge 'linux-review/Emmanuel-Grumbach/mac80211-don-t-WARN-on-bad-WMM-parameters-from-buggy-APs/20180327-180036' into devel-spot-201803272204
git bisect bad ccf31c36bad5be0c7fbd4ce6e82b4410a7478da9 # 02:41 B 0 11 25 0 Merge 'wireless-drivers-next/master' into devel-spot-201803272204
git bisect bad 2105e74ef7120fa7b12d5c571763c0f6d06a75e9 # 03:02 B 0 9 22 0 Merge 'pza/reset/next' into devel-spot-201803272204
git bisect bad 9a76dd69d30110dcecf0716dc961c93349da942b # 03:22 B 0 4 19 1 Merge 'linux-review/Vijendar-Mukunda/ASoC-dwc-I2S-Controller-instance-param-added/20180327-175125' into devel-spot-201803272204
git bisect bad ed6c6d580da3d088d4c3cb449e1bf3fbb4a6d66a # 03:44 B 0 5 19 0 Merge 'tip/x86/cleanups' into devel-spot-201803272204
git bisect good 16d1cb0bc43642a4d934631a73c5210ad2499e2f # 04:08 G 11 0 0 0 x86/dumpstack: Unify show_regs()
git bisect bad 07cde313b2d21f728cec2836db7cdb55476f7a26 # 04:26 B 0 5 19 0 x86/msr: Allow rdmsr_safe_on_cpu() to schedule
git bisect good 13cc36d76bc4f5a9801ae32630bc8240ba0cc522 # 04:46 G 11 0 0 0 x86/rtc: Stop using deprecated functions
# first bad commit: [07cde313b2d21f728cec2836db7cdb55476f7a26] x86/msr: Allow rdmsr_safe_on_cpu() to schedule
git bisect good 13cc36d76bc4f5a9801ae32630bc8240ba0cc522 # 04:51 G 31 0 2 2 x86/rtc: Stop using deprecated functions
# extra tests with debug options
git bisect bad 07cde313b2d21f728cec2836db7cdb55476f7a26 # 05:14 B 0 1 16 2 x86/msr: Allow rdmsr_safe_on_cpu() to schedule
# extra tests on HEAD of linux-devel/devel-spot-201803272204
git bisect bad c98e6b78ee92a4c5662febce64591980d77bd6c6 # 05:19 B 0 27 50 4 0day head guard for 'devel-spot-201803272204'
# extra tests on tree/branch tip/x86/cleanups
git bisect bad 67bbd7a8d6bcdc44cc27105ae8c374e9176ceaf1 # 05:47 B 0 7 23 2 x86/cpuid: Allow cpuid_read() to schedule
# extra tests with first bad commit reverted
git bisect good c885db74ec7feacddf4cce667615504892b756c8 # 06:05 G 11 0 1 1 Revert "x86/msr: Allow rdmsr_safe_on_cpu() to schedule"
# extra tests on tree/branch tip/master
git bisect bad 990d0525372f3f3bb5abcc527c8bb56a030c2b29 # 06:25 B 0 11 25 0 Merge branch 'x86/mm'
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/lkp Intel Corporation
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