Re: 2.6.35-rc2-git2: Reported regressions from 2.6.34

[Linus Torvalds <torvalds@linux-foundation.org>]

[ Added lots of cc's to direct specific people to look at the regressions 
  that may or may not be theirs... ]

On Wed, 9 Jun 2010, Rafael J. Wysocki wrote:
>
>  * Quite a few of the already reported regressions may be related to the bug
>    fixed by 386f40c86d6c8d5b717ef20620af1a750d0dacb4 (Revert "tty: fix a little
>    bug in scrup, vt.c"), so reporters please retest with this commit applied.]

>From a quick look, most of them look unrelated to that unfortunate bug. 
It's hard to tell for sure, of course (memory corruption can do pretty 
much anything), but I'm not seeing the 07200720.. pattern at least.

And some of them do seem to be bisected to likely culprits and/or have 
patches that are claimed to have fixed them.

> Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=16163
> Subject	: [2.6.35-rc1 Regression] i915: Commit cfecde causes VGA to stay off
> Submitter	: David John <davidjon@xenontk.org>
> Date		: 2010-06-02 12:52 (7 days old)
> Message-ID	: <4C065423.3000202@xenontk.org>
> References	: http://marc.info/?l=linux-kernel&m=127548313828613&w=2

That has a "reverting the commit fixes it", and a confirmation from Nick 
Bowler.

Eric, Carl: should I just revert that commit? Or do you have a fix?

> Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=16145
> Subject	: Unable to boot after "ACPI: Don't let acpi_pad needlessly mark TSC unstable"
> Submitter	: Tom Gundersen <teg@jklm.no>
> Date		: 2010-06-07 13:11 (2 days old)
> Handled-By	: Venkatesh Pallipadi <venki@google.com>

Hmm. This does seem to be a properly bisected commit, but at the same time 
it looks from the bugzilla like it's just pure luck on that machine that 
the acpi_pad driver happened to mark TSC unstable - so while the commit 
bisected is the real one, it's not the "deeper reason" for the problem.

Venki, any updates?

> Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=16129
> Subject	: BUG: using smp_processor_id() in preemptible [00000000] code: jbd2/sda2
> Submitter	: Jan Kreuzer <kontrollator@gmx.de>
> Date		: 2010-06-05 06:15 (4 days old)

This seems to have been introduced by

	commit 7cbaef9c83e58bbd4bdd534b09052b6c5ec457d5
	Author: Ingo Molnar <mingo@elte.hu>
	Date:   Sat Nov 8 17:05:38 2008 +0100

	    sched: optimize sched_clock() a bit
    
	    sched_clock() uses cycles_2_ns() needlessly - which is an irq-disabling
	    variant of __cycles_2_ns().
    
	    Most of the time sched_clock() is called with irqs disabled already.
	    The few places that call it with irqs enabled need to be updated.
    
	    Signed-off-by: Ingo Molnar <mingo@elte.hu>

and this seems to be one of those calling cases that need to be updated.

Ingo? The call trace is:

	BUG: using smp_processor_id() in preemptible [00000000] code: jbd2/sda2-8/337
	caller is native_sched_clock+0x3c/0x68
	Pid: 337, comm: jbd2/sda2-8 Not tainted 2.6.35-rc1jan+ #4
	Call Trace:
	[<ffffffff812362c5>] debug_smp_processor_id+0xc9/0xe4
	[<ffffffff8101059d>] native_sched_clock+0x3c/0x68
	[<ffffffff8101043d>] sched_clock+0x9/0xd
	[<ffffffff81212d7a>] blk_rq_init+0x97/0xa3
	[<ffffffff81214d71>] get_request+0x1c4/0x2d0
	[<ffffffff81214ea6>] get_request_wait+0x29/0x1a6
	[<ffffffff81215537>] __make_request+0x338/0x45b
	[<ffffffff812147c2>] generic_make_request+0x2bb/0x330
	[<ffffffff81214909>] submit_bio+0xd2/0xef
	[<ffffffff811413cb>] submit_bh+0xf4/0x116
	[<ffffffff81144853>] block_write_full_page_endio+0x89/0x96
	[<ffffffff81144875>] block_write_full_page+0x15/0x17
	[<ffffffff8119b00a>] ext4_writepage+0x356/0x36b
	[<ffffffff810e1f91>] __writepage+0x1a/0x39
	[<ffffffff810e32a6>] write_cache_pages+0x20d/0x346
	[<ffffffff810e3406>] generic_writepages+0x27/0x29
	[<ffffffff811ca279>] journal_submit_data_buffers+0x110/0x17d
	[<ffffffff811ca986>] jbd2_journal_commit_transaction+0x4cb/0x156d
	[<ffffffff811d0cba>] kjournald2+0x147/0x37a

(from the bugzilla thing)

> Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=16122
> Subject	: 2.6.35-rc1: WARNING at fs/fs-writeback.c:1142 __mark_inode_dirty+0x103/0x170
> Submitter	: Larry Finger <Larry.Finger@lwfinger.net>
> Date		: 2010-06-04 13:18 (5 days old)

Jens?

> Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=16120
> Subject	: Oops: 0000 [#1] SMP, unable to handle kernel NULL pointer dereference at (null)
> Submitter	: Alex Zhavnerchik <alex.vizor@gmail.com>
> Date		: 2010-06-04 09:25 (5 days old)
> Handled-By	: Eric Dumazet <eric.dumazet@gmail.com>

This one seems to have a patch in bugzilla.

> Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=16104
> Subject	: Radeon KMS does not start after merge of the new PM-Code
> Submitter	: Jan Kreuzer <kontrollator@gmx.de>
> Date		: 2010-06-02 07:47 (7 days old)

This one also has a patch in Bugzilla, I think Airlie is just waiting to 
calm down his queue and already removed the dependency on the temperature 
code. DaveA?

> Bug-Entry     : http://bugzilla.kernel.org/show_bug.cgi?id=16161
> Subject       : [2.6.35-rc1 regression] sysfs: cannot create duplicate filename ... XVR-600 related?
> Submitter     : Mikael Pettersson <mikpe@it.uu.se>
> Date          : 2010-06-01 19:57 (8 days old)
> Message-ID    : <19461.26166.427857.612983@pilspetsen.it.uu.se>
> References    : http://marc.info/?l=linux-kernel&m=127542227511925&w=2
>
> Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=16090
> Subject	: sysfs: cannot create duplicate filename
> Submitter	: Tobias <devnull@plzk.org>
> Date		: 2010-06-01 15:59 (8 days old)
> Handled-By	: Jesse Barnes <jbarnes@virtuousgeek.org>

These two look related. Both are related to that "slot" thing in sysfs 
PCI, but only one of them is marked as Jesse's. Jesse?

> Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=16037
> Subject	: NULL Pointer dereference in __ir_input_register/budget_ci_attach
> Submitter	: Sean Finney <seanius@debian.org>
> Date		: 2010-05-23 19:52 (17 days old)

Perhaps related to commit 13c24497086418010bf4f76378bcae241d7f59cd?

David Härdeman, Mauro Carvalho Chehab added to cc.

				Linus