Greetings,

0day kernel testing robot got the below dmesg and the first bad commit is

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

commit 857811a37129f5d2ba162d7be3986eff44724014
Author:     Boqun Feng <boqun.feng@gmail.com>
AuthorDate: Wed Mar 1 23:01:38 2017 +0800
Commit:     Ingo Molnar <mingo@kernel.org>
CommitDate: Thu Mar 2 09:00:39 2017 +0100

     locking/ww_mutex: Adjust the lock number for stress test
     
     Because there are only 12 bits in held_lock::references, so we only
     support 4095 nested lock held in the same time, adjust the lock number
     for ww_mutex stress test to kill one lockdep splat:
     
       [ ] [ BUG: bad unlock balance detected! ]
       [ ] kworker/u2:0/5 is trying to release lock (ww_class_mutex) at:
       [ ] ww_mutex_unlock()
       [ ] but there are no more locks to release!
       ...
     
     Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
     Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
     Cc: Andrew Morton <akpm@linux-foundation.org>
     Cc: Chris Wilson <chris@chris-wilson.co.uk>
     Cc: Fengguang Wu <fengguang.wu@intel.com>
     Cc: Linus Torvalds <torvalds@linux-foundation.org>
     Cc: Nicolai Hähnle <Nicolai.Haehnle@amd.com>
     Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
     Cc: Peter Zijlstra <peterz@infradead.org>
     Cc: Thomas Gleixner <tglx@linutronix.de>
     Link: http://lkml.kernel.org/r/20170301150138.hdixnmafzfsox7nn@tardis.cn.ibm.com
     Signed-off-by: Ingo Molnar <mingo@kernel.org>

7fb4a2cea6  locking/lockdep: Add nest_lock integrity test
857811a371  locking/ww_mutex: Adjust the lock number for stress test
c02ed2e75e  Linux 4.11-rc4
7f0c4a163a  Add linux-next specific files for 20170327
+-----------------------------------------------------+------------+------------+-----------+---------------+
|                                                     | 7fb4a2cea6 | 857811a371 | v4.11-rc4 | next-20170327 |
+-----------------------------------------------------+------------+------------+-----------+---------------+
| boot_successes                                      | 0          | 16         | 29        | 1             |
| boot_failures                                       | 221        | 42         | 64        | 9             |
| WARNING:at_kernel/locking/lockdep.c:#__lock_acquire | 221        |            |           |               |
| BUG:kernel_hang_in_boot_stage                       | 0          | 42         | 60        | 9             |
| BUG:kernel_hang_in_test_stage                       | 0          | 0          | 4         |               |
+-----------------------------------------------------+------------+------------+-----------+---------------+

[  319.426004] CPU 0 is now offline
[  319.426004] CPU 0 is now offline
[  319.427670] 
<kernel hangs here>

In some other cases the kernel hangs after the "clocksource: tsc: ..."
lines:

[    5.850623] Unpacking initramfs...
[    5.850623] Unpacking initramfs...
[   11.046171] debug: unmapping init [mem 0xffff9bcade91d000-0xffff9bcadffcffff]
[   11.046171] debug: unmapping init [mem 0xffff9bcade91d000-0xffff9bcadffcffff]
[   11.088197] Scanning for low memory corruption every 60 seconds
[   11.088197] Scanning for low memory corruption every 60 seconds
[   11.092145] des3_ede-x86_64: performance on this CPU would be suboptimal: disabling des3_ede-x86_64.
[   11.092145] des3_ede-x86_64: performance on this CPU would be suboptimal: disabling des3_ede-x86_64.
[   11.097470] camellia-x86_64: performance on this CPU would be suboptimal: disabling camellia-x86_64.
[   11.097470] camellia-x86_64: performance on this CPU would be suboptimal: disabling camellia-x86_64.
[   11.124182] twofish-x86_64-3way: performance on this CPU would be suboptimal: disabling twofish-x86_64-3way.
[   11.124182] twofish-x86_64-3way: performance on this CPU would be suboptimal: disabling twofish-x86_64-3way.
[   11.128731] PCLMULQDQ-NI instructions are not detected.
[   11.128731] PCLMULQDQ-NI instructions are not detected.
[   11.137487] AVX or AES-NI instructions are not detected.
[   11.137487] AVX or AES-NI instructions are not detected.
[   11.149155] CPU feature 'AVX registers' is not supported.
[   11.149155] CPU feature 'AVX registers' is not supported.
[   11.172390] CPU feature 'AVX registers' is not supported.
[   11.172390] CPU feature 'AVX registers' is not supported.
[   11.175234] AVX2 or AES-NI instructions are not detected.
[   11.175234] AVX2 or AES-NI instructions are not detected.
[   11.193555] AVX2 instructions are not detected.
[   11.193555] AVX2 instructions are not detected.
[   12.128030] tsc: Refined TSC clocksource calibration: 2926.330 MHz
[   12.128030] tsc: Refined TSC clocksource calibration: 2926.330 MHz
[   12.131287] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x2a2e6c2e1bb, max_idle_ns: 440795237926 ns
[   12.131287] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x2a2e6c2e1bb, max_idle_ns: 440795237926 ns


                                                           # HH:MM RESULT GOOD BAD GOOD_BUT_DIRTY DIRTY_NOT_BAD
git bisect start 6ec9c2f12955a217a0b7c1512fc7d889024e15b3 v4.10 --
git bisect  bad 34bbce9e344b47e8871273409632f525973afad4  # 17:11  B      4     1    0   1  Merge branch 'for-linus' of git://git.kernel.dk/linux-block
git bisect good 1802979ab1ee8ec5a72987ad518f5a91bf41cd89  # 17:34  G     52     0   52  54  Merge branch 'for-linus' of git://git.kernel.dk/linux-block
git bisect good 4f1f2b8f0818af9b0e21ba4b17ab615e29b4650d  # 18:00  G     52     0   52  56  Merge tag 'watchdog-for-linus-v4.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging
git bisect good 33a8b3e99dc68abfe25e140144ad268e70660be3  # 18:19  G     53     0   53  56  Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
git bisect good 26db8f992444a87465fc01b264b0317a3943e2b6  # 18:42  G     56     0   56  56  Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
git bisect  bad bd0f9b356d00aa241ced36fb075a07041c28d3b8  # 18:58  B      1     4    0   0  sched/headers: fix up header file dependency on <linux/sched/signal.h>
git bisect  bad 609b07b72d3caaa8eed3a238886467946b78fa5e  # 19:22  B      2     6    0   0  Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
git bisect  bad 500e1af25209a048daa1f1f86083d4849d5c555b  # 19:39  B      4     4    0   0  Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
git bisect good 2b232e0c3b3a09f3e33750aa20e314f1b80e5361  # 20:04  G     51     0   51  51  locking/ww_mutex: Replace cpu_relax() with cond_resched() for tests
git bisect  bad 857811a37129f5d2ba162d7be3986eff44724014  # 20:22  B      2     3    0   0  locking/ww_mutex: Adjust the lock number for stress test
git bisect good 7fb4a2cea6b18dab56d609530d077f168169ed6b  # 20:47  G     52     0   52  52  locking/lockdep: Add nest_lock integrity test
# first bad commit: [857811a37129f5d2ba162d7be3986eff44724014] locking/ww_mutex: Adjust the lock number for stress test
git bisect good 7fb4a2cea6b18dab56d609530d077f168169ed6b  # 21:14  G    158     0  158 212  locking/lockdep: Add nest_lock integrity test
# extra tests with CONFIG_DEBUG_INFO_REDUCED
git bisect  bad 857811a37129f5d2ba162d7be3986eff44724014  # 21:35  B      5     1    0   0  locking/ww_mutex: Adjust the lock number for stress test
# extra tests on HEAD of linux-devel/devel-catchup-201703271346
git bisect  bad 791a4b24aa658106743fb3917d08494fbd1f994f  # 21:35  B      0     5   28   9  0day head guard for 'devel-catchup-201703271346'
# extra tests on tree/branch linus/master
git bisect  bad c02ed2e75ef4c74e41e421acb4ef1494671585e8  # 21:35  B      8    60    0   3  Linux 4.11-rc4
# extra tests with first bad commit reverted
git bisect good 2b3df4779b539136f0a6152a23c069e72b254d16  # 21:55  G     55     0   55  55  Revert "locking/ww_mutex: Adjust the lock number for stress test"
# extra tests on tree/branch linux-next/master
git bisect  bad 7f0c4a163aa51c7b924bbafbe2013838d7ddaed0  # 22:17  B      1     6    0   0  Add linux-next specific files for 20170327

---
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