[Bug 103731] New: [DRM/i915][Bisected] Kernel panic in setup_vector_irq() with HDMI LPE driver while putting offline CPU thread back to online

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=103731

            Bug ID: 103731
           Summary: [DRM/i915][Bisected] Kernel panic in
                    setup_vector_irq() with HDMI LPE driver while putting
                    offline CPU thread back to online
           Product: DRI
           Version: XOrg git
          Hardware: x86-64 (AMD64)
                OS: Linux (All)
            Status: NEW
          Severity: major
          Priority: high
         Component: DRM/Intel
          Assignee: intel-gfx-bugs at lists.freedesktop.org
          Reporter: augustine.chen at intel.com
        QA Contact: intel-gfx-bugs at lists.freedesktop.org
                CC: intel-gfx-bugs at lists.freedesktop.org
     i915 platform: BSW/CHT
     i915 features: display/audio

Created attachment 135445
  --> https://bugs.freedesktop.org/attachment.cgi?id=135445&action=edit
Full dmesg

System Environment:
--------------------------
 -- Platform: CHT
 -- System architecture: x86_64
 -- Kernel version: 4.14.0-041400-generic
 -- Linux distribution: Ubuntu 16.04 LTS
 -- Mother board model: CHT T3 RVP with CHT-T3 D1 SOC (both T3 and T4 RVPs are
reproducible)
 -- Display connector: HDMI


Bug detailed description:
-----------------------------
While doing CPU thread online/offline test, the system hanging could be
observed when putting offline thread back to online. This issue is reproducible
since Kernel 4.11-rc1 and is still present in Kernel 4.14. This issue had been
bisected to happen since this commit eef57324d926f0d8c7a40069e7d26e0cb0651b47.
And after digging further, Kernel panic in setup_vector_irq() with debug
messages as below could be captured.

 ------------[ cut here ]------------
[   87.353072] irq 298 idata->chip->name hdmi_lpe_audio_irqchip
[   87.353072] irq 298 apic_chip_data
[   87.353073] irq 298 data->domain is NULL
[   87.353120] BUG: unable to handle kernel NULL pointer dereference at (null)
[   87.353132] IP: setup_vector_irq+0x1ba/0x230
[   87.353133] PGD 0


Reproduce steps:
----------------------------
1. check cpuinfo $ grep "processor" /proc/cpuinfo
2. disable cpu[1-3] $ echo 0 > /sys/devices/system/cpu/cpu[1-3]/online
3. enable cpu[1-3] $ echo 1 > /sys/devices/system/cpu/cpu[1-3]/online <-- issue
happens, system hangs.


First bad commit:
----------------------------
commit eef57324d926f0d8c7a40069e7d26e0cb0651b47

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