RE: Linux 2.6.16-rc3

RE: Linux 2.6.16-rc3

[Brown, Len]

>> >- In http://bugzilla.kernel.org/show_bug.cgi?id=5989, Sanjoy 
>> >Mahajan has  another regression, but he's off collecting more info.
>> 
>> We're talking here about a system from 1999 where Windows 98
>> refuses to run in ACPI mode and instead runs in APM mode.
>
>If it worked before a change which was installed, it's a regression
>regardless of whether another OS tries to use ACPI on that system or
>not.  I don't understand how one can use that fact to label this as
>not a regression from Linux's perspective.

I don't think anybody claimed this isn't a regression for the 600X.
Sanjoy has done a wonderful job documenting that.

My point is that it that on the grand scale of bugs serious enough
to have an effect on the course of 2.6.16, this one doesn't qualify
unless the same issue is seen on other systems.

-Len

Re: Linux 2.6.16-rc3

[Andrew Morton]

"Brown, Len" <len.brown@intel.com> wrote:
>
> My point is that it that on the grand scale of bugs serious enough
>  to have an effect on the course of 2.6.16, this one doesn't qualify
>  unless the same issue is seen on other systems.

I think we can assume that it will be seen there.  2.6.16 is going into
distros and will have more exposure than 2.6.15, let alone 2.6.16-rcX.

Re: Linux 2.6.16-rc3

[Sanjoy Mahajan]

> I think we can assume that it will be seen there.  2.6.16 is going into
> distros and will have more exposure than 2.6.15, let alone
> 2.6.16-rcX.

A related point is that S3 sleep/wake problems are very difficult to
debug.  The bug is often not reproducible (I've had a few of those).
Or it happens early in the wakeup, when the serial console hasn't been
restored to a working state (at least on some machines, see bugzilla
#4270).  Or the system has bugs that prevents its going to sleep,
which also prevents any wakeup problems from being investigated.  

Or they happen to regular users, who give up and say 'my laptop cannot
go to sleep in Linux, oh well'.  Besides being inconvenient, it gives
Linux a bad name, especially when people nearby have iBooks and
PowerBooks running MacOS that sleep and wake in 2-3 seconds, including
restoring networking and wireless.

So there's value in chasing any S3 bugs that can be reproduced,
especially those affecting sleeping.

The TP 600X is indeed old, and perhaps the bug is caused by an
otherwise fine change uncovering a 600X hardware or firmware bug
(perhaps the point that comment #8 at bugzilla 5989 is getting at).
However, one of the beauties of Linux, and a nightmare for developers,
is that Linux works on all sorts of hardware.  I don't know whether
this bug should affect the 2.6.16 schedule.  But I think its worth
solving eventually, if only to point where it's clear that it's unique
to this model.

-Sanjoy

`Never underestimate the evil of which men of power are capable.'
         --Bertrand Russell, _War Crimes in Vietnam_, chapter 1.

Re: Linux 2.6.16-rc3

[Arjan van de Ven]

On Mon, 2006-02-13 at 00:12 -0800, Andrew Morton wrote:
> "Brown, Len" <len.brown@intel.com> wrote:
> >
> > My point is that it that on the grand scale of bugs serious enough
> >  to have an effect on the course of 2.6.16, this one doesn't qualify
> >  unless the same issue is seen on other systems.
> 
> I think we can assume that it will be seen there.  2.6.16 is going into
> distros and will have more exposure than 2.6.15, 

2.6.15 went into distros as well, such as Fedora Core 4 ;)

Re: Linux 2.6.16-rc3

[Michal Jaegermann]

On Mon, Feb 13, 2006 at 09:57:48AM +0100, Arjan van de Ven wrote:
> On Mon, 2006-02-13 at 00:12 -0800, Andrew Morton wrote:
> > 
> > I think we can assume that it will be seen there.  2.6.16 is going into
> > distros and will have more exposure than 2.6.15, 
> 
> 2.6.15 went into distros as well, such as Fedora Core 4 ;)

And promptly broke laptop suspension.  See, for example:
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=180998

   Michal

Re: Linux 2.6.16-rc3

[Andrew Morton]

Michal Jaegermann <michal@harddata.com> wrote:
>
> On Mon, Feb 13, 2006 at 09:57:48AM +0100, Arjan van de Ven wrote:
> > On Mon, 2006-02-13 at 00:12 -0800, Andrew Morton wrote:
> > > 
> > > I think we can assume that it will be seen there.  2.6.16 is going into
> > > distros and will have more exposure than 2.6.15, 
> > 
> > 2.6.15 went into distros as well, such as Fedora Core 4 ;)
> 
> And promptly broke laptop suspension.  See, for example:
> https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=180998
> 

That's suspend-to-disk, yes?

Dave, would you have the 2.6.15-1.1830_FC4 -> 2.6.15-1.1831_FC4 details
handy?  There surely can't be much difference?

There seem to be several ACPI problems there.  Do we have a reliable means
of feeding such reports up into the (for example) acpi developers?

<I have this vaguely unsettled feeling that distros must get more bug
reports than the usptream developers, yet we hear so little about it>

Re: Linux 2.6.16-rc3

[Dave Jones]

On Mon, Feb 13, 2006 at 07:28:38PM -0800, Andrew Morton wrote:
 > Michal Jaegermann <michal@harddata.com> wrote:
 > >
 > > On Mon, Feb 13, 2006 at 09:57:48AM +0100, Arjan van de Ven wrote:
 > > > On Mon, 2006-02-13 at 00:12 -0800, Andrew Morton wrote:
 > > > > 
 > > > > I think we can assume that it will be seen there.  2.6.16 is going into
 > > > > distros and will have more exposure than 2.6.15, 
 > > > 
 > > > 2.6.15 went into distros as well, such as Fedora Core 4 ;)
 > > 
 > > And promptly broke laptop suspension.  See, for example:
 > > https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=180998
 > > 
 > 
 > That's suspend-to-disk, yes?
 > 
 > Dave, would you have the 2.6.15-1.1830_FC4 -> 2.6.15-1.1831_FC4 details
 > handy?  There surely can't be much difference?

Tiny changes.
- The icmp remote DoS fix.
- Dropped a patch that broke booting with 'quiet' bootparam
- the 'dm_crypt: zero key before freeing it' change

 > There seem to be several ACPI problems there.  Do we have a reliable means
 > of feeding such reports up into the (for example) acpi developers?
 > 
 > <I have this vaguely unsettled feeling that distros must get more bug
 > reports than the usptream developers, yet we hear so little about it>

I'd love more hours in the day to push more of them upstream, as
I bet would other vendors kernel maintainers.

Should anyone want to drink from the firehose that is 'redhat kernel bugzilla',
let me know, and I'll see if I can't get a fedora-kernel-bugs mailing
list or the like set up.

Some subsystem maintainers (ACPI for example) really help out here,
and add acpi-bugzilla@list.sourceforge.net to all the Fedora ACPI bugs.
(I believe that list actually gets bug reports from other distro bugzillas too)

(There's also a few 'meta-bugs' -- enter FCMETA_ACPI as a bug id
and you get a link to a dependancy tree showing all the ACPI bugs
reported. There's a bunch of those for various subsystems which
makes it a little easier to track, though again, it's time-consuming
just sorting through stuff).  Off the top of my head, theres one
for USB, SCSI, ACPI, ALSA, SATA (All with FCMETA_ prefix)
Some of them are a bit sparse due to lack of time & effort so far.
		
		Dave

Re: Linux 2.6.16-rc3

[Arjan van de Ven]

> <I have this vaguely unsettled feeling that distros must get more bug
> reports than the usptream developers, yet we hear so little about it>

the number of quality reports (eg enough information to do anything)
isn't that high; Dave is pretty good in sending the good ones on, it
often takes time though to get all the basic info..

Re: Linux 2.6.16-rc3

[Michal Jaegermann]

On Mon, Feb 13, 2006 at 07:28:38PM -0800, Andrew Morton wrote:
> Michal Jaegermann <michal@harddata.com> wrote:
> >
> > On Mon, Feb 13, 2006 at 09:57:48AM +0100, Arjan van de Ven wrote:
> > > On Mon, 2006-02-13 at 00:12 -0800, Andrew Morton wrote:
> > > > 
> > > > I think we can assume that it will be seen there.  2.6.16 is going into
> > > > distros and will have more exposure than 2.6.15, 
> > > 
> > > 2.6.15 went into distros as well, such as Fedora Core 4 ;)
> > 
> > And promptly broke laptop suspension.  See, for example:
> > https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=180998
> > 
> 
> That's suspend-to-disk, yes?

No.  That is an S3 suspension to RAM.  On the box in question it
generally worked for quite a long while now provided
'acpi_sleep=s3_bios' was passed to a kernel or video would be
unrestorable.  It is Acer Travelmate 230 with i845G video.

I did not try on that laptop suspend-to-disk so far (and in this
moment the damn thing is just plain broken).

   Michal

Re: Linux 2.6.16-rc3

[Pavel Machek]

Hi!

> That's suspend-to-disk, yes?
> 
> Dave, would you have the 2.6.15-1.1830_FC4 -> 2.6.15-1.1831_FC4 details
> handy?  There surely can't be much difference?
> 
> There seem to be several ACPI problems there.  Do we have a reliable means
> of feeding such reports up into the (for example) acpi developers?
> 
> <I have this vaguely unsettled feeling that distros must get more bug
> reports than the usptream developers, yet we hear so little about it>

Its about 1:1 upstream:suse bugs for me... Unfortunately
suse bugs are often for old kernel...
-- 
64 bytes from 195.113.31.123: icmp_seq=28 ttl=51 time=448769.1 ms         

Re: Linux 2.6.16-rc3

[Lee Revell]

On Mon, 2006-02-13 at 20:08 -0700, Michal Jaegermann wrote:
> On Mon, Feb 13, 2006 at 09:57:48AM +0100, Arjan van de Ven wrote:
> > On Mon, 2006-02-13 at 00:12 -0800, Andrew Morton wrote:
> > > 
> > > I think we can assume that it will be seen there.  2.6.16 is going into
> > > distros and will have more exposure than 2.6.15, 
> > 
> > 2.6.15 went into distros as well, such as Fedora Core 4 ;)
> 
> And promptly broke laptop suspension.  See, for example:
> https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=180998

It broke suspension on YOUR laptop - the bug report does not give a make
and model.  2.6.15 would not have shipped if it broke suspend on the
developers' laptops.

Lee

Re: Linux 2.6.16-rc3

[Michal Jaegermann]

On Mon, Feb 13, 2006 at 10:30:56PM -0500, Lee Revell wrote:
> On Mon, 2006-02-13 at 20:08 -0700, Michal Jaegermann wrote:
> > On Mon, Feb 13, 2006 at 09:57:48AM +0100, Arjan van de Ven wrote:
> > > 
> > > 2.6.15 went into distros as well, such as Fedora Core 4 ;)
> > 
> > And promptly broke laptop suspension.  See, for example:
> > https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=180998
> 
> It broke suspension on YOUR laptop - the bug report does not give a make
> and model.

Yes, indeed.  It is Acer Travelmate 230 and it is using
'acpi_sleep=s3_bios'.  The bug report noted though that the
following showed up:

Yenta O2: res at 0x94/0xD4: 00/ca
Yenta O2: enabling read prefetch/write burst
    ACPI-0265: *** Error: No installed handler for fixed event [00000002]

which was not something which I have seen before and indeed on
another laptop with the same kernel is absent.  But it was also not
there on 230 with earlier kernels.

BTW - this another laptop mentioned above, which happens to be Acer
Travelmate 740, is doing suspend/resume with 2.6.15 kernel, and no
'acpi_sleep=s3_bios' is needed,  but shortly after such cycle both
an external mouse and a touchpad go crazy and a mouse pointer
refuses to move in X from the left screen edge.  Not very useful and
so far I did not found a way to reset rodents.  No problems of that
sort before I will try to suspend.  Always something "interesting".
It is actually possible that in this case this is a problem with
"ATI Radeon Mobility M6" video driver which gets upset by suspend
(or some other pieces driving display) but I do not really know.

   Michal

Re: Linux 2.6.16-rc3

[Arjan van de Ven]

On Mon, 2006-02-13 at 20:08 -0700, Michal Jaegermann wrote:
> On Mon, Feb 13, 2006 at 09:57:48AM +0100, Arjan van de Ven wrote:
> > On Mon, 2006-02-13 at 00:12 -0800, Andrew Morton wrote:
> > > 
> > > I think we can assume that it will be seen there.  2.6.16 is going into
> > > distros and will have more exposure than 2.6.15, 
> > 
> > 2.6.15 went into distros as well, such as Fedora Core 4 ;)
> 
> And promptly broke laptop suspension.  See, for example:
> https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=180998


fedora core 4 never really supported suspend in the first place tho..

Re: Linux 2.6.16-rc3

[Sanjoy Mahajan]

> I don't think anybody claimed this isn't a regression for the 600X.

I narrowed it further.  The short story is that this commit (diff below
sig) makes the second S3 sleep go into the endless loop, if the loaded
modules are exactly thermal, processor, intel_agp, and agpgart:

53f11d4ff8797bcceaf014e62bd39f16ce84baec is first bad commit
diff-tree 53f11d4ff8797bcceaf014e62bd39f16ce84baec (from 02b28a33aae93a3b53068e0858d62f8bcaef60a3)
Author: Len Brown <len.brown@intel.com>
Date:   Mon Dec 5 16:46:36 2005 -0500

    [ACPI] Enable Embedded Controller (EC) interrupt mode by default
    
    "ec_intr=0" reverts to polling
    "ec_burst=" no longer exists.
    
    Signed-off-by: Len Brown <len.brown@intel.com>
    Acked-by: Luming Yu <luming.yu@intel.com>

:040000 040000 9eec66712c68ebe372b2fb2c8d78bdc99df942ab e7e62cd09983730aee468edd4ba1cce50786b7e5 M	Documentation
:040000 040000 6e7db46918f6124f64a11f6757560078a8a27519 aa8abb1023024902300cb2e7a5bf74acd8c579e8 M	drivers

If I boot with ec_intr=0, the second sleep works fine.

Here is the full story.  First I tried a system with the minimal set of
modules to boot and run X (S3 sleep-wake wrecks the VGA consoles, but X
restores fine with 'chvt 1; sleep 0.5 ; chvt 7' on wakeup).  So I
stopped every service and unloaded all modules possible, which left only
intel_agp and agpgart.  Then, for each of the usual loaded modules
(except for sound modules, which often has sleep-wake problems anyway),
I tried:

1. Load the module
2. S3 sleep-wake-sleep-wake
3. Unload the module

to see whether the second sleep went into the infinite loop (visible
across the console).  The one culprit I found was 'thermal' (which
brings in 'processor').  Other modules didn't trigger the problem.

Then I recompiled using a minimal config, with only networking (for X to
work) and the acpi modules, and maybe a few others that I couldn't
avoid, and retested to make sure 'thermal' still triggered the problem,
which it did.  I used this config, or one just like it for 2.6.15, as a
base for all other kernels in the bisection search, using the nearest
ancestor's .config and then
   yes '' | make oldconfig
to make the new .config

Eventually bisection converged to the commit above, and then I retested
that kernel with 'ec_intr=0'.

Is this a problem with the TP 600X hardware, in which case I'll just use
ec_intr=0 forever, or is there more software debugging (DSDT or related
to the diff)?  I can turn on gobs of ACPI debugging and send the useful
parts of the log file.

In the bisection, many kernels worked fine, meaning that the second S3
cycle returned and I could compile the next bisection kernel.  In doing
that I noticed another problem, that the fan would not turn on with some
of these good kernels even though the system was hot enough (plenty of
chance for it to turn on since the next compile heated up the CPU).  For
example, acpi -t showed

     Thermal 1: ok, 46.0 degrees C
     Thermal 2: active[0], 42.0 degrees C
     Thermal 3: ok, 31.0 degrees C
     Thermal 4: ok, 34.0 degrees C

but the fan was off.  

So whenever I had a good kernel (meaning taht S3 sleep-wake-sleep-wake
returned), I checked whether the fan would turn on, to collect data for
a separate bisection search.  However, the data seems inconsistent.  If
I feed the data to a fresh git bisect, it complains about one commit
being marked both good and bad.  So I'll ask on the git list about that
issue.

-Sanjoy

`A society of sheep must in time beget a government of wolves.'
   - Bertrand de Jouvenal


diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 5dffcfe..2ad64ef 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -452,6 +452,11 @@ running once the system is up.
 
 	eata=		[HW,SCSI]
 
+	ec_intr=	[HW,ACPI] ACPI Embedded Controller interrupt mode
+			Format: <int>
+			0: polling mode
+			non-0: interrupt mode (default)
+
 	eda=		[HW,PS2]
 
 	edb=		[HW,PS2]
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index bb3963b..d4366ad 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -73,7 +73,7 @@ static struct acpi_driver acpi_ec_driver
 	.class = ACPI_EC_CLASS,
 	.ids = ACPI_EC_HID,
 	.ops = {
-		.add = acpi_ec_poll_add,
+		.add = acpi_ec_intr_add,
 		.remove = acpi_ec_remove,
 		.start = acpi_ec_start,
 		.stop = acpi_ec_stop,
@@ -147,7 +147,7 @@ static union acpi_ec *ec_ecdt;
 
 /* External interfaces use first EC only, so remember */
 static struct acpi_device *first_ec;
-static int acpi_ec_poll_mode = EC_POLL;
+static int acpi_ec_poll_mode = EC_INTR;
 
 /* --------------------------------------------------------------------------
                              Transaction Management
@@ -1594,4 +1594,4 @@ static int __init acpi_ec_set_intr_mode(
 	return 0;
 }
 
-__setup("ec_burst=", acpi_ec_set_intr_mode);
+__setup("ec_intr=", acpi_ec_set_intr_mode);

RE: Linux 2.6.16-rc3

[Brown, Len]

>i have a bug similar to:
>http://bugzilla.kernel.org/show_bug.cgi?id=6038 (marked as blocking by
>Andrew) on my laptop.

6038 is in NEEDINFO.
If no submitter participates, it may never get fixed.

-Len

RE: Linux 2.6.16-rc3

[Brown, Len]

 
>- In http://bugzilla.kernel.org/show_bug.cgi?id=5989, Sanjoy 
>Mahajan has  another regression, but he's off collecting more info.

We're talking here about a system from 1999 where Windows 98
refuses to run in ACPI mode and instead runs in APM mode.
So I don't consider a regression on this box as "serious" --
I consider that it works in ACPI mode at all as "miraculous":-)

However, I do think the issue merits investigation in the event
that it has an effect on systems newer than 6 years old.

thanks,
-Len

Re: Linux 2.6.16-rc3

[David S. Miller]

From: "Brown, Len" <len.brown@intel.com>
Date: Mon, 13 Feb 2006 02:07:50 -0500

> >- In http://bugzilla.kernel.org/show_bug.cgi?id=5989, Sanjoy 
> >Mahajan has  another regression, but he's off collecting more info.
> 
> We're talking here about a system from 1999 where Windows 98
> refuses to run in ACPI mode and instead runs in APM mode.

If it worked before a change which was installed, it's a regression
regardless of whether another OS tries to use ACPI on that system or
not.  I don't understand how one can use that fact to label this as
not a regression from Linux's perspective.

Re: Linux 2.6.16-rc3

[Sanjoy Mahajan]

> systems newer than 6 years old.

According to the sticker on the bottom, this model was made in
04/2000, so the 6 years is right.

> We're talking here about a system from 1999 where Windows 98 refuses
> to run in ACPI mode and instead runs in APM mode.

I haven't tried Windows 98 on this machine, but Windows 98SE would run
in ACPI mode if it weren't for a cheap hack by IBM.  The latest BIOS
(1.11), which I'm using, claims to be from 1999.  However, that date
is almost surely wrong.  The readme/changelog with the BIOS update
diskette is dated Sept 20, 2001 and contains this note about the 1.01
update:

 - (Fix) If Windows 98 Second Edition is installed as APM mode and
         an updated BIOS is installed with a BIOS date 12/02/99 or 
         later, Windows 98SE will change the mode from APM to ACPI 
         whenever a New hardware profile is created.  So this BIOS 
         set the date to 11-30-99. 

Probably IBM marked all the BIOS dates as 11-30-99 in order to work
around this W98SE misfeature.  My guess is that BIOS 1.11 is really
from Sept 2001, or 4.5 years ago.  Old, but not octagenerian!

> I consider that it works in ACPI mode at all as "miraculous":-)

Amen to that.  I was very pleased when the combination of newer ACPI
releases plus my modifying the DSDT made S3 work.

> I do think the issue merits investigation ...

Although I have little idea of what sections of code to modify,
especially since the commit in question merges two well travelled
branches, I'm happy to test patches.

-Sanjoy

`Never underestimate the evil of which men of power are capable.'
         --Bertrand Russell, _War Crimes in Vietnam_, chapter 1.

RE: Linux 2.6.16-rc3

[Brown, Len]

 
>- http://bugzilla.kernel.org/show_bug.cgi?id=6049 - another acpi
>  regression.  We have the actual offending commit here.

per my note in the bug report, I believe that this failure
is not related to the "offending commit", and thus that commit
should not be reverted.  I believe that this failure is because
the system is booted with "pci=noacpi" in IOAPIC mode --
and unsuportable configuration -- and will endeavor to confirm...

thanks,
-Len

Re: Linux 2.6.16-rc3

[Andrew Morton]

We still have some serious bugs, several of which are in 2.6.15 as well:

- The scsi_cmd leak, which I don't think is fixed.

- The some-x86_64-boxes-use-GFP_DMA-from-bio-layer bug, which causes
  oom-killings.

- The skbuff_head_cache leak, which has been around since at least
  2.6.11.  Another box-killer, but is seems very hard to hit. 
  (mki@mozone.net, "the dreaded oom-killer (reproducable in 2.6.11 -
  2.6.16-rc1) :(")

- http://bugzilla.kernel.org/show_bug.cgi?id=6060: an apparent ACPI
  regression.

- Nathan's "sysfs-related oops during module unload", which Greg seems to
  have under control.

- http://bugzilla.kernel.org/show_bug.cgi?id=6049 - another acpi
  regression.  We have the actual offending commit here.

- A couple of random tty-related oopses reported by Jesper Juhl.  We
  don't know why these happened - they appear to not be related to the tty
  buffering changes.

- http://bugzilla.kernel.org/show_bug.cgi?id=6038, another box-killing
  acpi regression.

- Various reports similar to
  http://bugzilla.kernel.org/show_bug.cgi?id=6011, seemingly related to USB
  PCI quirk handling.

- "Ben Castricum" <lk@bencastricum.nl> reports that ppp has started
  exhibiting mysterious failures (again).

- Nasty warnings from scsi about kobject-layer things being called from
  irq context.  James has a push-it-to-process-context patch which sadly
  assumes kmalloc() is immortal, but no other fix seems to have offered
  itself.

- In http://bugzilla.kernel.org/show_bug.cgi?id=5989, Sanjoy Mahajan has
  another regression, but he's off collecting more info.

- Helge Hafting reports a usb printer regression - I don't know if that's
  still live?

- "Carlo E.  Prelz" <fluido@fluido.as> has another USB/ehci regression
  ("ATI RS480-based motherboard: stuck while booting with kernel >= 2.6.15
  rc1").

- Gerrit Bruchhuser <gbruchhaeuser@gmx.de> seems to have an aic7xxx
  regression ("AHA-7850 doesn't detect scanner anymore") but he doesn't say
  which kernel got it right.

- http://bugzilla.kernel.org/show_bug.cgi?id=5914 - a sata bug (which is
  quite unremarkable :(), but this one is reported to eat filesystems.

- Patrizio Bassi <patrizio.bassi@gmail.com> has an alsa suspend
  regression ("alsa suspend/resume continues to fail for ens1370")

- Bjorn Nilsson <bni.swe@gmail.com> has an sk99lin regression ("3COM
  3C940, does not work anymore after upgrade to 2.6.15")

- Andrey Borzenkov <arvidjaar@mail.ru> has an acpi-cpufreq regression
  ("cannot unload acpi-cpufreq")

- "P.  Christeas" <p_christ@hol.gr> had an autofs regression ("Regression
  in Autofs, 2.6.15-git"), whic might be fixed now?

- ghrt <ghrt@dial.kappa.ro> reports an alsa regression ("PROBLEM: SB
  Live!  5.1 (emu10k1, rev.  0a) doesn't work with 2.6.15")

- jinhong hu <jinhong.hu@gmail.com> reports what appears to be a qlogic
  regression ("kernel 2.6.15 scsi problem")

- Benjamin LaHaise <bcrl@kvack.org> had an NFS problem ("NFS processes
  gettting stuck in D with currrent git").



These are clear regressions, reported in the last month by people who are
willing to test patches.  They're almost all in subsystems which have
active and professional maintainers.

Re: Linux 2.6.16-rc3

[Trond Myklebust]

On Sun, 2006-02-12 at 19:05 -0800, Andrew Morton wrote:
> We still have some serious bugs, several of which are in 2.6.15 as well:

> - Benjamin LaHaise <bcrl@kvack.org> had an NFS problem ("NFS processes
>   gettting stuck in D with currrent git").

...but which was apparently not repeatable:

        As of this afternoon's tree
        (6150c32589d1976ca8a5c987df951088c05a7542)  after the more
        recent set of nfs patches, it seems to be behaving itself.  Will
        keep sysrq enabled to see if it hits again, though.

I've had no news from Ben since then...

Cheers,
  Trond

Re: Linux 2.6.16-rc3

[Sanjoy Mahajan]

> In http://bugzilla.kernel.org/show_bug.cgi?id=5989, Sanjoy Mahajan has
> another regression, but he's off collecting more info.

I'm nearly done with bisecting (spent a day on a wild bisect goose
chase due to being careless) and I'm 95% sure the problem is
introduced by:

commit b8e4d89357fc434618a59c1047cac72641191805
Author: Bob Moore <robert.moore@intel.com>
Date:   Fri Jan 27 16:43:00 2006 -0500

    [ACPI] ACPICA 20060127

But I will know for sure shortly.

-Sanjoy

`Never underestimate the evil of which men of power are capable.'
         --Bertrand Russell, _War Crimes in Vietnam_, chapter 1.

Re: Linux 2.6.16-rc3

[Jeff Garzik]

Andrew Morton wrote:
> - http://bugzilla.kernel.org/show_bug.cgi?id=5914 - a sata bug (which is
>   quite unremarkable :(), but this one is reported to eat filesystems.

Issue closed, as the bug notes...

	Jeff

Re: Linux 2.6.16-rc3

[James Bottomley]

On Sun, 2006-02-12 at 19:05 -0800, Andrew Morton wrote:
> - The scsi_cmd leak, which I don't think is fixed.

Erm, you mean the leak caused by flush barriers?  That was verified as
fixed (albeit accidentally) in 2.6.16-rc1.

James

Re: Linux 2.6.16-rc3

[Arjan van de Ven]

On Sun, 2006-02-12 at 19:05 -0800, Andrew Morton wrote:
> We still have some serious bugs, several of which are in 2.6.15 as well:
> 
> - The scsi_cmd leak, which I don't think is fixed.

didn't this got nailed down to a 2.6.15 specific queueing bug, fixed in
2.6.16-rc ?

Re: Linux 2.6.16-rc3

[Jens Axboe]

On Sun, Feb 12 2006, Andrew Morton wrote:
> 
> We still have some serious bugs, several of which are in 2.6.15 as well:
> 
> - The scsi_cmd leak, which I don't think is fixed.

It is fixed in 2.6.16-rcX.

> - The some-x86_64-boxes-use-GFP_DMA-from-bio-layer bug, which causes
>   oom-killings.

Still pending.

-- 
Jens Axboe

Re: Linux 2.6.16-rc3

[Patrizio Bassi]

Andrew Morton ha scritto:
> We still have some serious bugs, several of which are in 2.6.15 as well:
>
> - The scsi_cmd leak, which I don't think is fixed.
>
> - The some-x86_64-boxes-use-GFP_DMA-from-bio-layer bug, which causes
>   oom-killings.
>
> - The skbuff_head_cache leak, which has been around since at least
>   2.6.11.  Another box-killer, but is seems very hard to hit. 
>   (mki@mozone.net, "the dreaded oom-killer (reproducable in 2.6.11 -
>   2.6.16-rc1) :(")
>
> - http://bugzilla.kernel.org/show_bug.cgi?id=6060: an apparent ACPI
>   regression.
>
> - Nathan's "sysfs-related oops during module unload", which Greg seems to
>   have under control.
>
> - http://bugzilla.kernel.org/show_bug.cgi?id=6049 - another acpi
>   regression.  We have the actual offending commit here.
>
> - A couple of random tty-related oopses reported by Jesper Juhl.  We
>   don't know why these happened - they appear to not be related to the tty
>   buffering changes.
>
> - http://bugzilla.kernel.org/show_bug.cgi?id=6038, another box-killing
>   acpi regression.
>
> - Various reports similar to
>   http://bugzilla.kernel.org/show_bug.cgi?id=6011, seemingly related to USB
>   PCI quirk handling.
>
> - "Ben Castricum" <lk@bencastricum.nl> reports that ppp has started
>   exhibiting mysterious failures (again).
>
> - Nasty warnings from scsi about kobject-layer things being called from
>   irq context.  James has a push-it-to-process-context patch which sadly
>   assumes kmalloc() is immortal, but no other fix seems to have offered
>   itself.
>
> - In http://bugzilla.kernel.org/show_bug.cgi?id=5989, Sanjoy Mahajan has
>   another regression, but he's off collecting more info.
>
> - Helge Hafting reports a usb printer regression - I don't know if that's
>   still live?
>
> - "Carlo E.  Prelz" <fluido@fluido.as> has another USB/ehci regression
>   ("ATI RS480-based motherboard: stuck while booting with kernel >= 2.6.15
>   rc1").
>
> - Gerrit Bruchhuser <gbruchhaeuser@gmx.de> seems to have an aic7xxx
>   regression ("AHA-7850 doesn't detect scanner anymore") but he doesn't say
>   which kernel got it right.
>
> - http://bugzilla.kernel.org/show_bug.cgi?id=5914 - a sata bug (which is
>   quite unremarkable :(), but this one is reported to eat filesystems.
>
> - Patrizio Bassi <patrizio.bassi@gmail.com> has an alsa suspend
>   regression ("alsa suspend/resume continues to fail for ens1370")
>
> - Bjorn Nilsson <bni.swe@gmail.com> has an sk99lin regression ("3COM
>   3C940, does not work anymore after upgrade to 2.6.15")
>
> - Andrey Borzenkov <arvidjaar@mail.ru> has an acpi-cpufreq regression
>   ("cannot unload acpi-cpufreq")
>
> - "P.  Christeas" <p_christ@hol.gr> had an autofs regression ("Regression
>   in Autofs, 2.6.15-git"), whic might be fixed now?
>
> - ghrt <ghrt@dial.kappa.ro> reports an alsa regression ("PROBLEM: SB
>   Live!  5.1 (emu10k1, rev.  0a) doesn't work with 2.6.15")
>
> - jinhong hu <jinhong.hu@gmail.com> reports what appears to be a qlogic
>   regression ("kernel 2.6.15 scsi problem")
>
> - Benjamin LaHaise <bcrl@kvack.org> had an NFS problem ("NFS processes
>   gettting stuck in D with currrent git").
>
>
>
> These are clear regressions, reported in the last month by people who are
> willing to test patches.  They're almost all in subsystems which have
> active and professional maintainers.
>
>   
Really sad to say, but my Alsa ens1370 regression due to suspend problem
is still there.
Only fix is reboot actually. Ready to patch :)

PS.

i have a bug similar to:
http://bugzilla.kernel.org/show_bug.cgi?id=6038 (marked as blocking by
Andrew)
on my laptop.

but my dma expiry problem only happens during suspend.
I have a Sis 630 chipset with a 2.5" hitachi drive.
Been there...for ages..i can say: always...never got a working 2.6 kernel.
However in my poor opinion it's not blocking on my system, just boring.


Patrizio

Re: Linux 2.6.16-rc3

[Takashi Iwai]

At Sun, 12 Feb 2006 19:05:20 -0800,
Andrew Morton wrote:
> 
> - Patrizio Bassi <patrizio.bassi@gmail.com> has an alsa suspend
>   regression ("alsa suspend/resume continues to fail for ens1370")

It's not a "regression".  PM didn't work with ens1370 at all in the
eralier version.

About the problem there, I have no idea now what's wrong.  The
suspend-to-disk works fine if the driver is built as module but not as
built-in kernel.


> - ghrt <ghrt@dial.kappa.ro> reports an alsa regression ("PROBLEM: SB
>   Live!  5.1 (emu10k1, rev.  0a) doesn't work with 2.6.15")

I couldn't find this bugzilla entry...


Takashi

Re: Linux 2.6.16-rc3

[Patrizio Bassi]

Takashi Iwai ha scritto:
> At Sun, 12 Feb 2006 19:05:20 -0800,
> Andrew Morton wrote:
>   
>> - Patrizio Bassi <patrizio.bassi@gmail.com> has an alsa suspend
>>   regression ("alsa suspend/resume continues to fail for ens1370")
>>     
>
> It's not a "regression".  PM didn't work with ens1370 at all in the
> eralier version.
>
> About the problem there, I have no idea now what's wrong.  The
> suspend-to-disk works fine if the driver is built as module but not as
> built-in kernel.
>
>
>   
i wrote "regression" because before (ehm...exactly don't know...about
2.6.14 time)
after suspend i had to restart my distro's mixer values service or i
couldn't hear anything.
and...ok..it was boring but worked.

now i get 0x660 errors if i try to restore values and device seems dead,
just flood the syslog.
sound apps slow down (like 100% cpu usage) and no sound produced.

only fix is reboot.


>> - ghrt <ghrt@dial.kappa.ro> reports an alsa regression ("PROBLEM: SB
>>   Live!  5.1 (emu10k1, rev.  0a) doesn't work with 2.6.15")
>>     
>
> I couldn't find this bugzilla entry...
>
>
> Takashi
>
>   

Re: Linux 2.6.16-rc3

[Takashi Iwai]

At Mon, 13 Feb 2006 13:37:55 +0100,
Patrizio Bassi wrote:
> 
> Takashi Iwai ha scritto:
> > At Sun, 12 Feb 2006 19:05:20 -0800,
> > Andrew Morton wrote:
> >   
> >> - Patrizio Bassi <patrizio.bassi@gmail.com> has an alsa suspend
> >>   regression ("alsa suspend/resume continues to fail for ens1370")
> >>     
> >
> > It's not a "regression".  PM didn't work with ens1370 at all in the
> > eralier version.
> >
> > About the problem there, I have no idea now what's wrong.  The
> > suspend-to-disk works fine if the driver is built as module but not as
> > built-in kernel.
> >
> >
> >   
> i wrote "regression" because before (ehm...exactly don't know...about
> 2.6.14 time)
> after suspend i had to restart my distro's mixer values service or i
> couldn't hear anything.
> and...ok..it was boring but worked.

You abused the function which wasn't officially supported :)


Takashi

Re: Linux 2.6.16-rc3

[Patrizio Bassi]

Takashi Iwai ha scritto:
> At Mon, 13 Feb 2006 13:37:55 +0100,
> Patrizio Bassi wrote:
>   
>> Takashi Iwai ha scritto:
>>     
>>> At Sun, 12 Feb 2006 19:05:20 -0800,
>>> Andrew Morton wrote:
>>>   
>>>       
>>>> - Patrizio Bassi <patrizio.bassi@gmail.com> has an alsa suspend
>>>>   regression ("alsa suspend/resume continues to fail for ens1370")
>>>>     
>>>>         
>>> It's not a "regression".  PM didn't work with ens1370 at all in the
>>> eralier version.
>>>
>>> About the problem there, I have no idea now what's wrong.  The
>>> suspend-to-disk works fine if the driver is built as module but not as
>>> built-in kernel.
>>>
>>>
>>>   
>>>       
>> i wrote "regression" because before (ehm...exactly don't know...about
>> 2.6.14 time)
>> after suspend i had to restart my distro's mixer values service or i
>> couldn't hear anything.
>> and...ok..it was boring but worked.
>>     
>
> You abused the function which wasn't officially supported :)
>
>
> Takashi
>
>   
nice i'm an abuser! :)

ok, seriously..that's bad, because before it was not implemented, so ok...
but now it fails with errors (and make apps not working properly) which
is worse.

Patrizio

Re: Linux 2.6.16-rc3

[Takashi Iwai]

At Mon, 13 Feb 2006 14:31:23 +0100,
Patrizio Bassi wrote:
> 
> Takashi Iwai ha scritto:
> > At Mon, 13 Feb 2006 13:37:55 +0100,
> > Patrizio Bassi wrote:
> >   
> >> Takashi Iwai ha scritto:
> >>     
> >>> At Sun, 12 Feb 2006 19:05:20 -0800,
> >>> Andrew Morton wrote:
> >>>   
> >>>       
> >>>> - Patrizio Bassi <patrizio.bassi@gmail.com> has an alsa suspend
> >>>>   regression ("alsa suspend/resume continues to fail for ens1370")
> >>>>     
> >>>>         
> >>> It's not a "regression".  PM didn't work with ens1370 at all in the
> >>> eralier version.
> >>>
> >>> About the problem there, I have no idea now what's wrong.  The
> >>> suspend-to-disk works fine if the driver is built as module but not as
> >>> built-in kernel.
> >>>
> >>>
> >>>   
> >>>       
> >> i wrote "regression" because before (ehm...exactly don't know...about
> >> 2.6.14 time)
> >> after suspend i had to restart my distro's mixer values service or i
> >> couldn't hear anything.
> >> and...ok..it was boring but worked.
> >>     
> >
> > You abused the function which wasn't officially supported :)
> >
> >
> > Takashi
> >
> >   
> nice i'm an abuser! :)
> 
> ok, seriously..that's bad, because before it was not implemented, so ok...
> but now it fails with errors (and make apps not working properly) which
> is worse.

My rough guess is the initialization order, the resume was called too
early.

What about to put sleep between snd_ensoniq_chip_init() and
snd_ak4531_resume()?  Or put more delay in snd_ak4531_resume()?


Takashi

Re: Linux 2.6.16-rc3

[Patrizio Bassi]

Takashi Iwai ha scritto:
> At Mon, 13 Feb 2006 14:31:23 +0100,
> Patrizio Bassi wrote:
>   
>> Takashi Iwai ha scritto:
>>     
>>> At Mon, 13 Feb 2006 13:37:55 +0100,
>>> Patrizio Bassi wrote:
>>>   
>>>       
>>>> Takashi Iwai ha scritto:
>>>>     
>>>>         
>>>>> At Sun, 12 Feb 2006 19:05:20 -0800,
>>>>> Andrew Morton wrote:
>>>>>   
>>>>>       
>>>>>           
>>>>>> - Patrizio Bassi <patrizio.bassi@gmail.com> has an alsa suspend
>>>>>>   regression ("alsa suspend/resume continues to fail for ens1370")
>>>>>>     
>>>>>>         
>>>>>>             
>>>>> It's not a "regression".  PM didn't work with ens1370 at all in the
>>>>> eralier version.
>>>>>
>>>>> About the problem there, I have no idea now what's wrong.  The
>>>>> suspend-to-disk works fine if the driver is built as module but not as
>>>>> built-in kernel.
>>>>>
>>>>>
>>>>>   
>>>>>       
>>>>>           
>>>> i wrote "regression" because before (ehm...exactly don't know...about
>>>> 2.6.14 time)
>>>> after suspend i had to restart my distro's mixer values service or i
>>>> couldn't hear anything.
>>>> and...ok..it was boring but worked.
>>>>     
>>>>         
>>> You abused the function which wasn't officially supported :)
>>>
>>>
>>> Takashi
>>>
>>>   
>>>       
>> nice i'm an abuser! :)
>>
>> ok, seriously..that's bad, because before it was not implemented, so ok...
>> but now it fails with errors (and make apps not working properly) which
>> is worse.
>>     
>
> My rough guess is the initialization order, the resume was called too
> early.
>
> What about to put sleep between snd_ensoniq_chip_init() and
> snd_ak4531_resume()?  Or put more delay in snd_ak4531_resume()?
>
>
> Takashi
>
>   
i'm almost sure the problem is not there (or, at least not only)
infact i get 0x660 errors (or better a long flood...) while suspending too.

there may be a bug or problem during suspending, and these problems
affect the normal resume.

however sleep is not always trustable...soif you think that's an init
problem you may add a
boolean value to check if init is completed or not and poll for TRUE
value in the resume function.

but, as i wrote before, i'm not sure the problem is **only** there.

Patrizio

Re: Linux 2.6.16-rc3

[Takashi Iwai]

At Mon, 13 Feb 2006 15:34:28 +0100,
Patrizio Bassi wrote:
> 
> Takashi Iwai ha scritto:
> > At Mon, 13 Feb 2006 14:31:23 +0100,
> > Patrizio Bassi wrote:
> >   
> >> Takashi Iwai ha scritto:
> >>     
> >>> At Mon, 13 Feb 2006 13:37:55 +0100,
> >>> Patrizio Bassi wrote:
> >>>   
> >>>       
> >>>> Takashi Iwai ha scritto:
> >>>>     
> >>>>         
> >>>>> At Sun, 12 Feb 2006 19:05:20 -0800,
> >>>>> Andrew Morton wrote:
> >>>>>   
> >>>>>       
> >>>>>           
> >>>>>> - Patrizio Bassi <patrizio.bassi@gmail.com> has an alsa suspend
> >>>>>>   regression ("alsa suspend/resume continues to fail for ens1370")
> >>>>>>     
> >>>>>>         
> >>>>>>             
> >>>>> It's not a "regression".  PM didn't work with ens1370 at all in the
> >>>>> eralier version.
> >>>>>
> >>>>> About the problem there, I have no idea now what's wrong.  The
> >>>>> suspend-to-disk works fine if the driver is built as module but not as
> >>>>> built-in kernel.
> >>>>>
> >>>>>
> >>>>>   
> >>>>>       
> >>>>>           
> >>>> i wrote "regression" because before (ehm...exactly don't know...about
> >>>> 2.6.14 time)
> >>>> after suspend i had to restart my distro's mixer values service or i
> >>>> couldn't hear anything.
> >>>> and...ok..it was boring but worked.
> >>>>     
> >>>>         
> >>> You abused the function which wasn't officially supported :)
> >>>
> >>>
> >>> Takashi
> >>>
> >>>   
> >>>       
> >> nice i'm an abuser! :)
> >>
> >> ok, seriously..that's bad, because before it was not implemented, so ok...
> >> but now it fails with errors (and make apps not working properly) which
> >> is worse.
> >>     
> >
> > My rough guess is the initialization order, the resume was called too
> > early.
> >
> > What about to put sleep between snd_ensoniq_chip_init() and
> > snd_ak4531_resume()?  Or put more delay in snd_ak4531_resume()?
> >
> >
> > Takashi
> >
> >   
> i'm almost sure the problem is not there (or, at least not only)
> infact i get 0x660 errors (or better a long flood...) while suspending too.

IIRC, suspend calls resume callback once to revive the devices back.
So, basically you see the same problem here.


Takashi

Re: Linux 2.6.16-rc3

[Rafael J. Wysocki]

On Monday 13 February 2006 13:02, Takashi Iwai wrote:
> At Sun, 12 Feb 2006 19:05:20 -0800,
> Andrew Morton wrote:
> > 
> > - Patrizio Bassi <patrizio.bassi@gmail.com> has an alsa suspend
> >   regression ("alsa suspend/resume continues to fail for ens1370")
> 
> It's not a "regression".  PM didn't work with ens1370 at all in the
> eralier version.
> 
> About the problem there, I have no idea now what's wrong.  The
> suspend-to-disk works fine if the driver is built as module but not as
> built-in kernel.

That may be related to the fact that modular drivers are not present in
memory during resume (just a thought).

Greetings,
Rafael

Re: Linux 2.6.16-rc3

[Takashi Iwai]

At Mon, 13 Feb 2006 14:09:51 +0100,
Rafael J. Wysocki wrote:
> 
> On Monday 13 February 2006 13:02, Takashi Iwai wrote:
> > At Sun, 12 Feb 2006 19:05:20 -0800,
> > Andrew Morton wrote:
> > > 
> > > - Patrizio Bassi <patrizio.bassi@gmail.com> has an alsa suspend
> > >   regression ("alsa suspend/resume continues to fail for ens1370")
> > 
> > It's not a "regression".  PM didn't work with ens1370 at all in the
> > eralier version.
> > 
> > About the problem there, I have no idea now what's wrong.  The
> > suspend-to-disk works fine if the driver is built as module but not as
> > built-in kernel.
> 
> That may be related to the fact that modular drivers are not present in
> memory during resume (just a thought).

I think the modular drivers are on memory but the order of
re-initialization is different.


Takashi

Re: Linux 2.6.16-rc3

[Rafael J. Wysocki]

On Monday 13 February 2006 14:51, Takashi Iwai wrote:
> At Mon, 13 Feb 2006 14:09:51 +0100,
> Rafael J. Wysocki wrote:
> > 
> > On Monday 13 February 2006 13:02, Takashi Iwai wrote:
> > > At Sun, 12 Feb 2006 19:05:20 -0800,
> > > Andrew Morton wrote:
> > > > 
> > > > - Patrizio Bassi <patrizio.bassi@gmail.com> has an alsa suspend
> > > >   regression ("alsa suspend/resume continues to fail for ens1370")
> > > 
> > > It's not a "regression".  PM didn't work with ens1370 at all in the
> > > eralier version.
> > > 
> > > About the problem there, I have no idea now what's wrong.  The
> > > suspend-to-disk works fine if the driver is built as module but not as
> > > built-in kernel.
> > 
> > That may be related to the fact that modular drivers are not present in
> > memory during resume (just a thought).
> 
> I think the modular drivers are on memory but the order of
> re-initialization is different.

No, they are not (this is the part I'm sure of).  software_resume() is called
before any modules have a chance to be loaded unless you boot with
noresume, load them from an initrd and start the resume manually.

Greetings,
Rafael

Re: Linux 2.6.16-rc3

[Greg KH]

On Sun, Feb 12, 2006 at 07:05:20PM -0800, Andrew Morton wrote:
> 
> We still have some serious bugs, several of which are in 2.6.15 as well:
> 
> - Nathan's "sysfs-related oops during module unload", which Greg seems to
>   have under control.

Yes, this isn't a "regression" but has been there for a while.  It can
also only be triggered by a root user, so it's severity is much lower.

> - Various reports similar to
>   http://bugzilla.kernel.org/show_bug.cgi?id=6011, seemingly related to USB
>   PCI quirk handling.

I have a patch for this, which will be going to Linus later tonight.

> - Nasty warnings from scsi about kobject-layer things being called from
>   irq context.  James has a push-it-to-process-context patch which sadly
>   assumes kmalloc() is immortal, but no other fix seems to have offered
>   itself.

This has been the case for a long time.  I don't really think there is a
rush to get this fixed, but I really like James's proposed patch.  It's
up to him if he feels it is ready for 2.6.16 or not.

> - Helge Hafting reports a usb printer regression - I don't know if that's
>   still live?

He never reported back, and one other person who reported this, figured
out that it was bad ram in the system.  Replacing that fixed the issue.
I've also printed a lot of stuff here (tax time...) and had no problems.

> - "Carlo E.  Prelz" <fluido@fluido.as> has another USB/ehci regression
>   ("ATI RS480-based motherboard: stuck while booting with kernel >= 2.6.15
>   rc1").

Fixed by the previously mentioned EHCI quirk/handoff patch that will be
going to Linus.

So, that's it for the USB stuff, thankfully.

thanks,

greg k-h

Re: Linux 2.6.16-rc3

[James Bottomley]

On Mon, 2006-02-13 at 12:38 -0800, Greg KH wrote:
> > - Nasty warnings from scsi about kobject-layer things being called
> from
> >   irq context.  James has a push-it-to-process-context patch which
> sadly
> >   assumes kmalloc() is immortal, but no other fix seems to have
> offered
> >   itself.
> 
> This has been the case for a long time.  I don't really think there is
> a
> rush to get this fixed, but I really like James's proposed patch.
> It's
> up to him if he feels it is ready for 2.6.16 or not.

Well, I can't solve the problem that it requires memory allocation from
IRQ context to operate.  Based on that, it's an unsafe interface.  I'm
going to put it inside SCSI for 2.6.16, since it's better than what we
have now, but I don't think we can export it globally.

James

Re: Linux 2.6.16-rc3

[James Bottomley]

On Tue, 2006-02-14 at 10:34 -0600, James Bottomley wrote:
> Well, I can't solve the problem that it requires memory allocation from
> IRQ context to operate.  Based on that, it's an unsafe interface.  I'm
> going to put it inside SCSI for 2.6.16, since it's better than what we
> have now, but I don't think we can export it globally.

OK, this is what I'm proposing as the device model fix.  What it does is
thread context checking APIs throughout the device subsystem.  SCSI can
then use it simply via device_put_process_context().  Since we have to
supply the kref_work; I'd plan to do that as an additional element in
struct scsi_device.

This, by itself, won't solve the SCSI target problem, but I plan to fix
that via a device model addition which would have target alloc waiting
around for any deleted targets to disappear.

Since this is planned for post 2.6.16, we have plenty of time to argue
about it.

James

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 6b355bd..4ae42de 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -338,10 +338,10 @@ struct device * get_device(struct device
  *	put_device - decrement reference count.
  *	@dev:	device in question.
  */
-void put_device(struct device * dev)
+void put_device_process_context(struct device * dev, struct kref_work *work)
 {
 	if (dev)
-		kobject_put(&dev->kobj);
+	  kobject_put_process_context(&dev->kobj, work);
 }
 
 
@@ -445,7 +445,7 @@ EXPORT_SYMBOL_GPL(device_register);
 EXPORT_SYMBOL_GPL(device_del);
 EXPORT_SYMBOL_GPL(device_unregister);
 EXPORT_SYMBOL_GPL(get_device);
-EXPORT_SYMBOL_GPL(put_device);
+EXPORT_SYMBOL_GPL(put_device_process_context);
 
 EXPORT_SYMBOL_GPL(device_create_file);
 EXPORT_SYMBOL_GPL(device_remove_file);
diff --git a/include/linux/device.h b/include/linux/device.h
index 58df18d..ac9d457 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -396,7 +396,13 @@ extern int (*platform_notify_remove)(str
  *
  */
 extern struct device * get_device(struct device * dev);
-extern void put_device(struct device * dev);
+extern void put_device_process_context(struct device * dev,
+				       struct kref_work *work);
+static inline void put_device(struct device *dev)
+{
+	put_device_process_context(dev, NULL);
+}
+						  
 
 
 /* drivers/base/power.c */
diff --git a/include/linux/kobject.h b/include/linux/kobject.h
index 2a8d8da..d079fea 100644
--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -76,7 +76,12 @@ extern int kobject_register(struct kobje
 extern void kobject_unregister(struct kobject *);
 
 extern struct kobject * kobject_get(struct kobject *);
-extern void kobject_put(struct kobject *);
+extern void kobject_put_process_context(struct kobject *, struct kref_work *);
+
+static inline void kobject_put(struct kobject *kobj)
+{
+	kobject_put_process_context(kobj, NULL);
+}
 
 extern char * kobject_get_path(struct kobject *, gfp_t);
 
diff --git a/include/linux/kref.h b/include/linux/kref.h
index 6fee353..16b15db 100644
--- a/include/linux/kref.h
+++ b/include/linux/kref.h
@@ -18,15 +18,29 @@
 #ifdef __KERNEL__
 
 #include <linux/types.h>
+#include <linux/workqueue.h>
 #include <asm/atomic.h>
 
 struct kref {
 	atomic_t refcount;
 };
 
+struct kref_work {
+	struct work_struct work;
+	struct kref *kref;
+	void (*release)(struct kref *kref);
+};
+
 void kref_init(struct kref *kref);
 void kref_get(struct kref *kref);
-int kref_put(struct kref *kref, void (*release) (struct kref *kref));
+int kref_put_process_context(struct kref *kref,
+			     void (*release) (struct kref *kref),
+			     struct kref_work *work);
+static inline int kref_put(struct kref *kref,
+			   void (*release) (struct kref *kref))
+{
+	return kref_put_process_context(kref, release, NULL);
+}
 
 #endif /* __KERNEL__ */
 #endif /* _KREF_H_ */
diff --git a/lib/kobject.c b/lib/kobject.c
index efe67fa..6b80c54 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -372,10 +372,10 @@ static void kobject_release(struct kref 
  *
  *	Decrement the refcount, and if 0, call kobject_cleanup().
  */
-void kobject_put(struct kobject * kobj)
+void kobject_put_process_context(struct kobject * kobj, struct kref_work *work)
 {
 	if (kobj)
-		kref_put(&kobj->kref, kobject_release);
+		kref_put_process_context(&kobj->kref, kobject_release, work);
 }
 
 
@@ -537,7 +537,7 @@ EXPORT_SYMBOL(kobject_init);
 EXPORT_SYMBOL(kobject_register);
 EXPORT_SYMBOL(kobject_unregister);
 EXPORT_SYMBOL(kobject_get);
-EXPORT_SYMBOL(kobject_put);
+EXPORT_SYMBOL(kobject_put_process_context);
 EXPORT_SYMBOL(kobject_add);
 EXPORT_SYMBOL(kobject_del);
 
diff --git a/lib/kref.c b/lib/kref.c
index 0d07cc3..66231cf 100644
--- a/lib/kref.c
+++ b/lib/kref.c
@@ -13,6 +13,7 @@
 
 #include <linux/kref.h>
 #include <linux/module.h>
+#include <linux/hardirq.h>
 
 /**
  * kref_init - initialize object.
@@ -33,27 +34,47 @@ void kref_get(struct kref *kref)
 	atomic_inc(&kref->refcount);
 }
 
+static void kref_release_process_context(void *data)
+{
+	struct kref_work *work = data;
+
+	work->release(work->kref);
+}
+
 /**
- * kref_put - decrement refcount for object.
+ * kref_put_user - decrement refcount for object and put in user context
  * @kref: object.
  * @release: pointer to the function that will clean up the object when the
  *	     last reference to the object is released.
  *	     This pointer is required, and it is not acceptable to pass kfree
  *	     in as this function.
+ * @work:    pointer to a kref_work used to take the release through user
+ *	     context (may be null)
  *
- * Decrement the refcount, and if 0, call release().
+ * Decrement the refcount, and if 0, call release().  If work is not null
+ * execute release via schedule_work if not in process context.
  * Return 1 if the object was removed, otherwise return 0.  Beware, if this
  * function returns 0, you still can not count on the kref from remaining in
  * memory.  Only use the return value if you want to see if the kref is now
  * gone, not present.
  */
-int kref_put(struct kref *kref, void (*release)(struct kref *kref))
+int kref_put_process_context(struct kref *kref,
+			     void (*release)(struct kref *kref),
+			     struct kref_work *work)
 {
 	WARN_ON(release == NULL);
 	WARN_ON(release == (void (*)(struct kref *))kfree);
 
 	if (atomic_dec_and_test(&kref->refcount)) {
-		release(kref);
+		if (!work || !in_interrupt())
+			release(kref);
+		else {
+			INIT_WORK(&work->work, kref_release_process_context,
+				  work);
+			schedule_work(&work->work);
+		}
+			
+			
 		return 1;
 	}
 	return 0;
@@ -61,4 +82,4 @@ int kref_put(struct kref *kref, void (*r
 
 EXPORT_SYMBOL(kref_init);
 EXPORT_SYMBOL(kref_get);
-EXPORT_SYMBOL(kref_put);
+EXPORT_SYMBOL(kref_put_process_context);

Re: Linux 2.6.16-rc3

[Russell King]

On Wed, Feb 15, 2006 at 08:56:00PM -0500, James Bottomley wrote:
> On Tue, 2006-02-14 at 10:34 -0600, James Bottomley wrote:
> > Well, I can't solve the problem that it requires memory allocation from
> > IRQ context to operate.  Based on that, it's an unsafe interface.  I'm
> > going to put it inside SCSI for 2.6.16, since it's better than what we
> > have now, but I don't think we can export it globally.
> 
> OK, this is what I'm proposing as the device model fix.  What it does is
> thread context checking APIs throughout the device subsystem.  SCSI can
> then use it simply via device_put_process_context().  Since we have to
> supply the kref_work; I'd plan to do that as an additional element in
> struct scsi_device.
> 
> This, by itself, won't solve the SCSI target problem, but I plan to fix
> that via a device model addition which would have target alloc waiting
> around for any deleted targets to disappear.
> 
> Since this is planned for post 2.6.16, we have plenty of time to argue
> about it.

This is probably an idiotic question, but if there's something in the
scsi release handler can't be called in non-process context, why can't
scsi queue up the release processing via the work API itself, rather
than having to have this additional code and complexity for everyone?

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core

Re: Linux 2.6.16-rc3

[Stefan Richter]

Russell King wrote:
> On Wed, Feb 15, 2006 at 08:56:00PM -0500, James Bottomley wrote:
[...]
>>OK, this is what I'm proposing as the device model fix.  What it does is
>>thread context checking APIs throughout the device subsystem.  SCSI can
>>then use it simply via device_put_process_context().
[...]
>>Since this is planned for post 2.6.16, we have plenty of time to argue
>>about it.
> 
> This is probably an idiotic question, but if there's something in the
> scsi release handler can't be called in non-process context, why can't
> scsi queue up the release processing via the work API itself, rather
> than having to have this additional code and complexity for everyone?

Moreover, why are SCSI release handlers called in non-process context in 
the first place? IMO the fix should be to make sure that SCSI release 
handlers are always called from process context --- by the respective 
layers which manage physical devices, i.e. one or more layers beneath 
SCSI core.
-- 
Stefan Richter
-=====-=-==- --=- =----
http://arcgraph.de/sr/

Re: Linux 2.6.16-rc3

[James Bottomley]

On Thu, 2006-02-16 at 17:12 +0000, Russell King wrote:
> This is probably an idiotic question, but if there's something in the
> scsi release handler can't be called in non-process context, why can't
> scsi queue up the release processing via the work API itself, rather
> than having to have this additional code and complexity for everyone?

It's because, in order to get a guaranteed single allocation for the
workqueue to execute in user context, I need to know when the release
will be called.  The only way to do that is to add the execute in
process context directly to kref_put.

James

Re: Linux 2.6.16-rc3

[Russell King]

On Thu, Feb 16, 2006 at 09:57:32AM -0800, James Bottomley wrote:
> On Thu, 2006-02-16 at 17:12 +0000, Russell King wrote:
> > This is probably an idiotic question, but if there's something in the
> > scsi release handler can't be called in non-process context, why can't
> > scsi queue up the release processing via the work API itself, rather
> > than having to have this additional code and complexity for everyone?
> 
> It's because, in order to get a guaranteed single allocation for the
> workqueue to execute in user context, I need to know when the release
> will be called.  The only way to do that is to add the execute in
> process context directly to kref_put.

Is there something in the driver model which would prevent something
like this?

static void scsi_release_process(void *p)
{
	struct my_work *work = p;
	struct device *dev = work->dev;

	/* destroy dev */

	kfree(work);
}

static void scsi_release(struct device *dev)
{
	struct my_work *work;

	work = kmalloc(sizeof(struct my_work), GFP_ATOMIC);
	if (work) {
		INIT_WORK(&work->work, scsi_release_process, work);
		work->dev = dev;
		schedule_work(&work->work);
	} else {
		printk(KERN_ERR ...);
	}
}

where scsi_release() is the function called by the device model on the
last put of a scsi device.

I guess is more or less what you're trying to do invasively via the
driver model.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core

Re: Linux 2.6.16-rc3

[James Bottomley]

On Thu, 2006-02-16 at 18:09 +0000, Russell King wrote:
> where scsi_release() is the function called by the device model on the
> last put of a scsi device.
> 
> I guess is more or less what you're trying to do invasively via the
> driver model.

Yes ... except I think more than just SCSI has the problem (and we
actually have it in more than one release function) so it seems like a
good candidate for a general abstraction.

James

Re: Linux 2.6.16-rc3

[Russell King]

On Thu, Feb 16, 2006 at 10:14:31AM -0800, James Bottomley wrote:
> On Thu, 2006-02-16 at 18:09 +0000, Russell King wrote:
> > where scsi_release() is the function called by the device model on the
> > last put of a scsi device.
> > 
> > I guess is more or less what you're trying to do invasively via the
> > driver model.
> 
> Yes ... except I think more than just SCSI has the problem (and we
> actually have it in more than one release function) so it seems like a
> good candidate for a general abstraction.

Maybe implementing it as a helper function would be the best and
simplest solution?

static void scsi_release(struct device *dev)
{
	schedule_release_process(dev, scsi_release_process);
}

where schedule_release_process() contains more or less what I posted
in the previous mailing.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core

Re: Linux 2.6.16-rc3

[James Bottomley]

On Thu, 2006-02-16 at 18:18 +0000, Russell King wrote:
> Maybe implementing it as a helper function would be the best and
> simplest solution?
> 
> static void scsi_release(struct device *dev)
> {
> 	schedule_release_process(dev, scsi_release_process);
> }
> 
> where schedule_release_process() contains more or less what I posted
> in the previous mailing.

That's almost exactly the execute_in_process_context() API that began
this discussion (and which Andi NAK'd).  However, it could possibly be
resurrected with the proviso that the caller has to feed in the
workqueue memory.  How would people feel about that?

James

Re: Linux 2.6.16-rc3

[Jens Axboe]

On Thu, Feb 16 2006, James Bottomley wrote:
> On Thu, 2006-02-16 at 18:18 +0000, Russell King wrote:
> > Maybe implementing it as a helper function would be the best and
> > simplest solution?
> > 
> > static void scsi_release(struct device *dev)
> > {
> > 	schedule_release_process(dev, scsi_release_process);
> > }
> > 
> > where schedule_release_process() contains more or less what I posted
> > in the previous mailing.
> 
> That's almost exactly the execute_in_process_context() API that began
> this discussion (and which Andi NAK'd).  However, it could possibly be
> resurrected with the proviso that the caller has to feed in the
> workqueue memory.  How would people feel about that?

That's what I suggested in the first place as well. I still think it's a
good idea, fwiw :)

-- 
Jens Axboe

Re: Linux 2.6.16-rc3

[James Bottomley]

On Thu, 2006-02-16 at 21:01 +0100, Jens Axboe wrote:
> That's what I suggested in the first place as well. I still think it's a
> good idea, fwiw :)

OK smarty pants ... some of us are a bit slower on the uptake.  How
about this then.  It won't solve the target problem, but it will solve
the device put.

James

[PATCH] add execute_in_process_context() API

We have several points in the SCSI stack (primarily for our device
functions) where we need to guarantee process context, but (given the
place where the last reference was released) we cannot guarantee this.

This API gets around the issue by executing the function directly if
the caller has process context, but scheduling a workqueue to execute
in process context if the caller doesn't have it.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

Index: BUILD-2.6/include/linux/workqueue.h
===================================================================
--- BUILD-2.6.orig/include/linux/workqueue.h	2006-02-17 13:02:00.000000000 -0600
+++ BUILD-2.6/include/linux/workqueue.h	2006-02-17 17:57:52.000000000 -0600
@@ -20,6 +20,12 @@
 	struct timer_list timer;
 };
 
+struct execute_work {
+	struct work_struct work;
+	void (*fn)(void *);
+	void *data;
+};
+
 #define __WORK_INITIALIZER(n, f, d) {				\
         .entry	= { &(n).entry, &(n).entry },			\
 	.func = (f),						\
@@ -74,6 +80,8 @@
 void cancel_rearming_delayed_work(struct work_struct *work);
 void cancel_rearming_delayed_workqueue(struct workqueue_struct *,
 				       struct work_struct *);
+int execute_in_process_context(void (*fn)(void *), void *,
+			       struct execute_work *);
 
 /*
  * Kill off a pending schedule_delayed_work().  Note that the work callback
Index: BUILD-2.6/kernel/workqueue.c
===================================================================
--- BUILD-2.6.orig/kernel/workqueue.c	2006-02-17 13:02:01.000000000 -0600
+++ BUILD-2.6/kernel/workqueue.c	2006-02-17 18:00:15.000000000 -0600
@@ -27,6 +27,7 @@
 #include <linux/cpu.h>
 #include <linux/notifier.h>
 #include <linux/kthread.h>
+#include <linux/hardirq.h>
 
 /*
  * The per-CPU workqueue (if single thread, we always use the first
@@ -476,6 +477,45 @@
 }
 EXPORT_SYMBOL(cancel_rearming_delayed_work);
 
+static void execute_in_process_context_work(void *data)
+{
+	void (*fn)(void *data);
+	struct execute_work *ew = data;
+
+	fn = ew->fn;
+	data = ew->data;
+
+	fn(data);
+}
+
+/**
+ * execute_in_process_context - reliably execute the routine with user context
+ * @fn:		the function to execute
+ * @data:	data to pass to the function
+ *
+ * Executes the function immediately if process context is available,
+ * otherwise schedules the function for delayed execution.
+ *
+ * Returns:	0 - function was executed
+ *		1 - function was scheduled for execution
+ */
+int execute_in_process_context(void (*fn)(void *data), void *data,
+			       struct execute_work *ew)
+{
+	if (!in_interrupt()) {
+		fn(data);
+		return 0;
+	}
+
+	INIT_WORK(&ew->work, execute_in_process_context_work, ew);
+	ew->fn = fn;
+	ew->data = data;
+	schedule_work(&ew->work);
+
+	return 1;
+}
+EXPORT_SYMBOL_GPL(execute_in_process_context);
+
 int keventd_up(void)
 {
 	return keventd_wq != NULL;

Re: Linux 2.6.16-rc3

[Greg KH]

On Fri, Feb 17, 2006 at 04:42:43PM -0800, James Bottomley wrote:
> On Thu, 2006-02-16 at 21:01 +0100, Jens Axboe wrote:
> > That's what I suggested in the first place as well. I still think it's a
> > good idea, fwiw :)
> 
> OK smarty pants ... some of us are a bit slower on the uptake.  How
> about this then.  It won't solve the target problem, but it will solve
> the device put.
> 
> James
> 
> [PATCH] add execute_in_process_context() API

I like it, nice job.

Acked-by: Greg Kroah-Hartma <gregkh@suse.de>

thanks,

greg k-h

Re: Linux 2.6.16-rc3

[Roland Dreier]

 > +/**
 > + * execute_in_process_context - reliably execute the routine with user context
 > + * @fn:		the function to execute
 > + * @data:	data to pass to the function
 > + *
 > + * Executes the function immediately if process context is available,
 > + * otherwise schedules the function for delayed execution.
 > + *
 > + * Returns:	0 - function was executed
 > + *		1 - function was scheduled for execution
 > + */
 > +int execute_in_process_context(void (*fn)(void *data), void *data,
 > +			       struct execute_work *ew)
 > +{
 > +	if (!in_interrupt()) {
 > +		fn(data);
 > +		return 0;
 > +	}

Is testing in_interrupt() really sufficient to make this work?  I seem
to remember that (at least) with CONFIG_PREEMPT disabled, there are
contexts where it is not safe to sleep but where both in_interrupt()
and in_atomic() still return 0.

 - R.

Re: Linux 2.6.16-rc3

[Matthew Wilcox]

On Fri, Feb 17, 2006 at 06:12:04PM -0800, Roland Dreier wrote:
>  > +int execute_in_process_context(void (*fn)(void *data), void *data,
>  > +			       struct execute_work *ew)
>  > +{
>  > +	if (!in_interrupt()) {
>  > +		fn(data);
>  > +		return 0;
>  > +	}
> 
> Is testing in_interrupt() really sufficient to make this work?  I seem
> to remember that (at least) with CONFIG_PREEMPT disabled, there are
> contexts where it is not safe to sleep but where both in_interrupt()
> and in_atomic() still return 0.

That's correct -- in process context, with PREEMPT disabled and a spinlock
held, it's unsafe to call this function.  It works well for the SCSI
usage (where it's called either in interrupt context or in user
context with no spinlocks held), but it's not *always* safe.

I think this needs to be documented in the kerneldoc.


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Re: Linux 2.6.16-rc3

[Helge Hafting]

Andrew Morton wrote:

>We still have some serious bugs, several of which are in 2.6.15 as well:
>
[...]

>- Helge Hafting reports a usb printer regression - I don't know if that's
>  still live?
>  
>
I tried printing four pages of graphichs with 2.6.16-rc3-mm1
and it worked fine.  When I had the problem I couldn't even print
three, I had to print the 10 pages I needed one by one.

So I believe the situation has improved.

Helge Hafting