Bug 38732

Summary: Linux 3.0-rc5 doesnt boot and hangs at rcu_sched_state ()
Product: Process Management Reporter: Maciej Rutecki (maciej.rutecki)
Component: SchedulerAssignee: Ingo Molnar (mingo)
Status: CLOSED CODE_FIX    
Severity: normal CC: florian, maciej.rutecki, paulmck, rjw, sunr2007
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 3.0-rc5 Subsystem:
Regression: Yes Bisected commit-id:
Bug Depends on:    
Bug Blocks: 36912    
Attachments: Fix for Ravi Kulkarni

Description Maciej Rutecki 2011-07-03 13:36:47 UTC 
Subject    : Linux 3.0-rc5 doesnt boot and hangs at rcu_sched_state ()
Submitter  : RKK <kulkarni.ravi4@gmail.com>
Date       : 2011-06-29 13:38
Message-ID : BANLkTikW6Xk8UMsOHLCnLn7STRzy8RaiJA@mail.gmail.com
References : http://marc.info/?l=linux-kernel&m=130935402722869&w=2

This entry is being used for tracking a regression from 2.6.39. Please don't
close it until the problem is fixed in the mainline.
Comment 1 Paul E. McKenney 2011-07-09 16:02:20 UTC 
Can you set up the SysRq key as described in Documentation/sysrq.txt?
This might help you get some information about what the system is doing
during the wait time.

My guess is that your kernel is spinning with interrupts disabled, and
that RCU eventually tries to complain about this.  The possible causes
of this are listed in Documentation/RCU/stallwarn.txt.
Comment 2 Florian Mickler 2011-07-12 21:11:15 UTC 
Patch: https://lkml.org/lkml/2011/7/10/282
Comment 3 Paul E. McKenney 2011-07-12 21:23:02 UTC 
Created attachment 65352 [details]
Fix for Ravi Kulkarni
Comment 4 Paul E. McKenney 2011-07-12 21:24:24 UTC 
It looks like I accidentally sent the real patch privately to Ravi, so I linked in the correct patch above.  Florian, please accept my apologies for the confusion.
Comment 5 Florian Mickler 2011-07-12 21:57:26 UTC 
No problem at all. It's just book-keeping which will sort itself out later anyway. It should in no way impede on any development/bugfixing. Thx for the note though. 

Ignore-Patch: https://lkml.org/lkml/2011/7/10/282
Patch: https://bugzilla.kernel.org/attachment.cgi?id=65352
Comment 6 Ravi Kumar Kulkarni 2011-07-13 12:31:55 UTC 
Hi 
I tested with Peter's patch below
https://lkml.org/lkml/2011/7/12/150 

and Paul's patch https://lkml.org/lkml/2011/7/12/313 
also works fine for me now. thanks.
Comment 7 Rafael J. Wysocki 2011-08-14 19:09:10 UTC 
Fixed by commit b0d304172f49061b4ff78f9e2b02719ac69c8a7e .