linux-kernel - Re: v4.4-rc8 based tip tree kernel hangs on boot.

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Message-ID: <20160115162011.GA2935@linux.vnet.ibm.com>
Date:	Fri, 15 Jan 2016 21:50:11 +0530
From:	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	Matt Fleming <matt@...eblueprint.co.uk>,
	Ingo Molnar <mingo@...e.hu>,
	LKML <linux-kernel@...r.kernel.org>, linux-efi@...r.kernel.org,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: v4.4-rc8 based tip tree kernel hangs on boot.

> 
> it's the first commit in the branch in fact.
> 
> To double check, it would be nice to check that applying that commit to v4.4 
> breaks the boot too:
> 
>   git checkout v4.4
>   git cherry-pick 21cdb6b568
> 

This actually boots. i.e cherry-pick 21cdb6b568 on top of v4.4 boots
well. Next I kept on adding cherry-picks from tip/x86/efi

git log --oneline tip/x86/efi looked like this 

e2c90dd x86/efi-bgrt: Replace early_memremap() with memremap()
98f9127 Merge tag 'efi-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into x86/efi
50a0cb5 x86/efi-bgrt: Fix kernel panic when mapping BGRT data
26d7f65 x86/efi: Preface all print statements with efi* tag
3bb9eee doc: efi-stub.txt: Fix arm64 paths
7f83773 efi/esrt: Don't preformat name
ff3d0a1 Documentation/x86: Update EFI memory region description
67a9108 x86/efi: Build our own page table structures
c9f2a9a x86/efi: Hoist page table switching code into efi_call_virt()
b61a76f x86/efi: Map RAM into the identity page table for mixed mode
edc3b91 x86/mm/pat: Ensure cpa->pfn only contains page frame numbers
21cdb6b x86/mm: Page align the '_end' symbol to avoid pfn conversion bugs


So when I cherry-pick 67a9108 "x86/efi: Build our own page table
structures", the built kernel stops booting.

i.e until until I cherry-pick c9f2a9a, the kernel boots.

I still have to verify why git bisect was failing to give the right
commit.

Attached the dmesg of a good kernel boot as requested by Matt.

--
Thanks and Regards
Srikar

> ... but assuming the bisection is reliable, I'd say the evidence is pretty 
> conclusive already.
> 
> Srikar, could you please send the good and bad System.map files, so that we see 
> what the effects of the aligning were? The two interesting sha1's to test are:
> 
>   21cdb6b56843: first bad commit
>   6ffeba960734: last good commit (parent commit of 21cdb6b56843)
> 
> Thanks,
> 
> 	Ingo
> 

-- 
Thanks and Regards
Srikar Dronamraju

Download attachment "dmesg_good.txt.bz2" of type "application/octet-stream" (25675 bytes)