Bug 34262

Summary: Enabling CONFIG_X86_X2APIC results in hard lock up on Intel i7-2820/QM67 platform
Product: Platform Specific/Hardware Reporter: Alex Dubov (oakad)
Component: x86-64Assignee: platform_x86_64 (platform_x86_64)
Status: RESOLVED DUPLICATE    
Severity: normal CC: akpm, alan, hansb
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 2.6.38.4 Subsystem:
Regression: Yes Bisected commit-id:

Description Alex Dubov 2011-05-03 04:39:46 UTC 
When CONFIG_X86_X2APIC is set, the machine in question (Lenovo W520) will lock up during early stages of system boot. Machine suddenly becomes completely unresponsive and no further diagnostics can be obtained.

Kernel boots correctly until root file system is mounted and udev starts its "settle" phase, loading the modules for pending uevents. There seems to be no correlation between the modules being loaded and the lock up event occurring, yet it always happens during this stage.

If X2APIC is disabled, everything works fine.

I marked this as regression as setting this option never used to cause me any trouble on other machines (including slightly older Xeon boxes).
Comment 1 Andrew Morton 2011-05-03 23:48:43 UTC 
From which kernel version is this a regression?
Comment 2 Alex Dubov 2011-05-04 04:37:11 UTC 
(In reply to comment #1)
> From which kernel version is this a regression?

Apparently it's not a regression, sorry.

Both machines I've thought to be a reference for this (with 2.6.37 and 2.6.37.2 kernels) have this option not set, even though I was sure they do.
Comment 3 hansbee 2012-04-06 00:44:42 UTC 
See also Bug 43054
Comment 4 Alan 2012-08-23 13:50:01 UTC 

*** This bug has been marked as a duplicate of bug 43054 ***