FYI, we noticed the following commit:

commit: 33da94bd89b485777e253cf48ebc4638cf844022 ("perf/core: add a rb-tree index to inactive_groups")
url: https://github.com/0day-ci/linux/commits/David-Carrillo-Cisneros/optimize-ctx-switch-with-rb-tree/20170110-203936


in testcase: boot

on test machine: qemu-system-i386 -enable-kvm -cpu Haswell,+smep,+smap -m 360M

caused below changes:


+------------------------------------------+------------+------------+
|                                          | aa3557bdba | 33da94bd89 |
+------------------------------------------+------------+------------+
| boot_successes                           | 10         | 2          |
| boot_failures                            | 0          | 6          |
| BUG:unable_to_handle_kernel              | 0          | 6          |
| Oops:#[##]                               | 0          | 6          |
| Kernel_panic-not_syncing:Fatal_exception | 0          | 6          |
+------------------------------------------+------------+------------+



[    5.126053] LKP: waiting for network...
[    5.126521] 
[   14.436584] sock: process `trinity-main' is using obsolete setsockopt SO_BSDCOMPAT
[   15.993001] BUG: unable to handle kernel NULL pointer dereference at   (null)
[   15.994612] IP: rb_erase+0x3b2/0x790
[   15.995527] *pde = 00000000 
[   15.996499] Oops: 0000 [#1]
[   15.997316] Modules linked in:
[   15.998236] CPU: 0 PID: 402 Comm: trinity-main Not tainted 4.9.0-02684-g33da94b #1
[   16.000071] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-20161025_171302-gandalf 04/01/2014
[   16.002153] task: ca61ac00 task.stack: cb164000
[   16.003158] EIP: rb_erase+0x3b2/0x790
[   16.004069] EFLAGS: 00010046 CPU: 0
[   16.004956] EAX: 00000000 EBX: 00000000 ECX: 00000000 EDX: 00001723
[   16.006160] ESI: 00001722 EDI: cb1d8028 EBP: cb165dd0 ESP: cb165db4
[   16.007371]  DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068
[   16.008475] CR0: 80050033 CR2: 00000000 CR3: 0b1d2000 CR4: 000406d0
[   16.009760] DR0: 00000000 DR1: 080d6000 DR2: 00000000 DR3: 00000000
[   16.010974] DR6: ffff0ff0 DR7: 0051060a
[   16.011912] Call Trace:
[   16.012696]  ctx_sched_groups_del+0x5c/0xb0
[   16.013677]  list_del_event+0x239/0x240
[   16.014613]  __perf_remove_from_context+0x47/0x130


To reproduce:

        git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git
        cd lkp-tests
        bin/lkp qemu -k <bzImage> job-script  # job-script is attached in this email



Thanks,
Xiaolong