Greetings, 0day kernel testing robot got the below dmesg and the first bad commit is commit 8ae3e4082d915e7191e06fff38258f5a8bde981e Author: Vincent Guittot <vincent.guittot(a)linaro.org&gt; AuthorDate: Thu Dec 22 09:14:15 2016 +0100 Commit: Vincent Guittot <vincent.guittot(a)linaro.org&gt; CommitDate: Thu Dec 22 09:14:15 2016 +0100 sched: force update of blocked load of idle cpus When idle, the blocked load of CPUs will be updated only when an idle load balance is triggered which may never happen. Because of this uncertainty on the execution of idle load balance, the load and the shares of idle cfs_rq can stay artificially high and steal shares and running time to busy cfs_rqs of the task group. Add a new light idle load balance state which ensures that blocked loads are perioddiccally updated and decayed. Signed-off-by: Vincent Guittot <vincent.guittot(a)linaro.org&gt; +-------------------------------------------------------+------------+------------+------------+ | | 6b94780e45 | 8ae3e4082d | 41ccf6b62c | +-------------------------------------------------------+------------+------------+------------+ | boot_successes | 70 | 13 | 11 | | boot_failures | 4 | 11 | 8 | | BUG:kernel_reboot-without-warning_in_test_stage | 4 | | | | BUG:unable_to_handle_kernel | 0 | 11 | 8 | | Oops | 0 | 11 | 8 | | EIP_is_at_run_rebalance_domains | 0 | 11 | | | Kernel_panic-not_syncing:Fatal_exception_in_interrupt | 0 | 11 | 8 | | calltrace:smpboot_thread_fn | 0 | 1 | | +-------------------------------------------------------+------------+------------+------------+ [ 1.661160] Warning: could not register annotated branches stats [ 1.678196] VFS: Disk quotas dquot_6.6.0 [ 1.678899] VFS: Dquot-cache hash table entries: 1024 (order 0, 4096 bytes) [ 1.680150] BUG: unable to handle kernel [ 1.680158] FS-Cache: Loaded [ 1.680947] NULL pointer dereference at 00000014 [ 1.681520] IP: [<8e0a4dd9>] run_rebalance_domains+0x99/0x330 [ 1.682202] *pde = 00000000 [ 1.682568] Oops: 0000 [#1] SMP [ 1.682933] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.9.0-rc8-00180-g8ae3e40 #1 [ 1.683794] task: 80196600 task.stack: 80198000 [ 1.684324] EIP: 0060:[<8e0a4dd9>] EFLAGS: 00210286 CPU: 1 [ 1.684948] EIP is at run_rebalance_domains+0x99/0x330 [ 1.685540] EAX: 971b6c74 EBX: fffb6e0d ECX: 00000000 EDX: 00000000 [ 1.686261] ESI: 972feec0 EDI: 00000001 EBP: 801cffac ESP: 801cff70 [ 1.686977] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 [ 1.687596] CR0: 80050033 CR2: 00000014 CR3: 0fbbd000 CR4: 00000690 [ 1.688321] Stack: [ 1.688559] 00000002 00000000 00000000 8e0a4d97 00000000 00000000 8f0cf360 801cfff8 [ 1.689569] 00200046 8019007b 00000000 000000d8 00000101 8f78021c 00000007 801cfff8 [ 1.690577] 8f0cf512 00000000 00000000 00000000 00000000 00000000 00000000 0000000a [ 1.691587] Call Trace: [ 1.691873] <IRQ> [ 1.692117] [<8e0a4d97>] ? run_rebalance_domains+0x57/0x330 [ 1.692778] [<8f0cf360>] ? __irqentry_text_end+0x5/0x5 [ 1.693387] [<8f0cf512>] __do_softirq+0x1b2/0x5c3 [ 1.693934] [<8f0cf360>] ? __irqentry_text_end+0x5/0x5 [ 1.694548] [<8e01e978>] do_softirq_own_stack+0x28/0x30 [ 1.695167] <EOI> [ 1.695398] [<8e067d0d>] irq_exit+0x5d/0xe0 [ 1.695900] [<8e036751>] smp_reschedule_interrupt+0x31/0x40 [ 1.696554] [<8f0ce5b4>] reschedule_interrupt+0x34/0x40 [ 1.697169] [<8f0ccb95>] ? native_safe_halt+0x5/0x10 [ 1.697742] [<8f0cc685>] default_idle+0xa5/0x230 [ 1.698293] [<8e0259be>] arch_cpu_idle+0xe/0x10 [ 1.698821] [<8f0cce25>] default_idle_call+0x45/0x50 [ 1.699410] [<8e0ae71b>] cpu_startup_entry+0x17b/0x330 [ 1.700007] [<8e038212>] start_secondary+0x1c2/0x260 [ 1.700588] Code: 00 00 c7 44 24 04 00 00 00 00 c7 04 24 02 00 00 00 31 d2 b8 e8 27 7a 8f e8 35 49 01 00 b8 74 7c a6 8f 64 03 05 04 61 a6 8f 8b 10 <8b> 42 14 0f af 42 48 e8 db e5 03 00 85 c0 8b 0d 80 32 78 8f 75 [ 1.703699] EIP: [<8e0a4dd9>] [ 1.704041] run_rebalance_domains+0x99/0x330 [ 1.704544] SS:ESP 0068:801cff70 [ 1.704925] CR2: 0000000000000014 [ 1.705322] ---[ end trace de2bd44e7901131e ]--- [ 1.705847] Kernel panic - not syncing: Fatal exception in interrupt git bisect start 41ccf6b62c89a66013bc6e6b5e15cf9a96d56a8f 69973b830859bc6529a7a0468ba0d80ee5117826 -- git bisect bad 6f18c3c5034ce5bc2fd46a3487c2f8745ff6c820 # 22:59 0- 6 Merge 'vincent.guittot/sched/pelt' into devel-catchup-201612222007 git bisect good 47c4aab4b7c9c02823553055cd22d56cea244d05 # 23:09 24+ 0 Merge 'tip/WIP.hotplug' into devel-catchup-201612222007 git bisect good 1fb5a886d697b549946c4e048109e4d0ba5207f0 # 23:19 22+ 0 Merge 'linux-review/Niklas-S-derlund/linux-kernel-h-Fix-DIV_ROUND_CLOSEST-to-support-negative-divisors/20161222-183734' into devel-catchup-201612222007 git bisect good e62b7af03c47932a4965b53852e0ab4d198a9b19 # 23:29 24+ 3 Merge 'linux-review/Jaehoon-Chung/phy-core-check-whether-ops-callback-function-is-assigned/20161222-183354' into devel-catchup-201612222007 git bisect good 0f128d4fd5a4fc472076aaad9cf3c33fc5141113 # 23:38 24+ 3 Merge 'linux-review/Nicolas-Iooss/HID-intel-ish-hid-add-printf-attribute-to-print_log/20161222-183054' into devel-catchup-201612222007 git bisect bad c6afbd4106e456c59bba365d51102bc765e695d3 # 23:52 0- 3 Merge branches 'sched-fix-noise-regression' and 'sched-update-blocked-idle-cpu' into sched/pelt git bisect good 7ba6395ebdf4cf91a11f6738d25b8c49bbc090a2 # 00:01 24+ 3 sched: fix group_entity's share update git bisect good c4f4baea9ba73687ce247a3deee6006e2d1a7170 # 00:12 24+ 2 sched: fix noise regression git bisect bad 8ae3e4082d915e7191e06fff38258f5a8bde981e # 00:20 0- 11 sched: force update of blocked load of idle cpus # first bad commit: [8ae3e4082d915e7191e06fff38258f5a8bde981e] sched: force update of blocked load of idle cpus git bisect good 6b94780e45c17b83e3e75f8aaca5a328db583c74 # 00:36 72+ 4 sched/core: Use load_avg for selecting idlest group # extra tests with CONFIG_DEBUG_INFO_REDUCED git bisect bad 8ae3e4082d915e7191e06fff38258f5a8bde981e # 00:47 0- 6 sched: force update of blocked load of idle cpus # extra tests on HEAD of linux-devel/devel-catchup-201612222007 git bisect bad 41ccf6b62c89a66013bc6e6b5e15cf9a96d56a8f # 00:47 0- 8 0day head guard for 'devel-catchup-201612222007' # extra tests on tree/branch linux-devel/devel-catchup-201612221833 git bisect bad 17792173b666a8a7438fa8d291d31f305ab628dc # 02:17 0- 4 0day head guard for 'devel-catchup-201612221833' # extra tests with first bad commit reverted git bisect good 154ca6cb5806942e95dd31cbe1a8a78757dc12ad # 02:34 69+ 3 Revert "sched: force update of blocked load of idle cpus" # extra tests on tree/branch linus/master git bisect good eb254f323bd50ab7e3cc385f2fc641a595cc8b37 # 02:45 69+ 2 Merge branch 'x86-cache-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip # extra tests on tree/branch linux-next/master git bisect good 49358776a0a64bb2ea6301d12381659a8e3388ae # 03:03 72+ 13 Add linux-next specific files for 20161222 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/lkp Intel Corporation