2.6.23.8-rt11, tasks freezing

2.6.23.8-rt11, tasks freezing

[Juuso Alasuutari]

Hi,

I use vanilla kernels with realtime-preempt patches on a Core 2 E6600 running 
32-bit Linux. Kernels up to 2.6.22.1-rt9 work fine, but I'm experiencing 
strange freezing of some tasks with 2.6.23.8-rt11. (Actually all 2.6.23 
rt-kernels I've so far tried hang the same way.)

The system boots up nicely and seems to be running properly, until something 
tips it off and some commands begin to get "jammed". What seems to trigger it 
is accessing the hard disk, for instance doing something like `grep -r 
foo /var`. When it happens the desktop seems mostly responsive, but trying to 
run commands like `ls` will freeze the terminal. Other commands will succeed, 
for instance `ps aux` works as usual.

Alt-SysRq-w shows more than one blocked pdflush task, as well as metalog and 
whatever commands have become "jammed" so far, like `ls`.

I'll be happy to post more information, I just need to know what. I'd attach 
my .config here, but I can't access the computer from where I'm at the 
moment.

Juuso Alasuutari

Re: 2.6.23.8-rt11, tasks freezing

[Steven Rostedt]

On Wed, 21 Nov 2007, Juuso Alasuutari wrote:

> Hi,
>
> I use vanilla kernels with realtime-preempt patches on a Core 2 E6600 running
> 32-bit Linux. Kernels up to 2.6.22.1-rt9 work fine, but I'm experiencing
> strange freezing of some tasks with 2.6.23.8-rt11. (Actually all 2.6.23
> rt-kernels I've so far tried hang the same way.)

Could you try 2.6.23-rc8-rt1 and see if it hangs?
If not, then try 2.6.23-rc9-rt1, if that doesn't hang then try
2.6.23-rc9-rt2.

Reason being is that we've implemented a new RCU preempt logic. -rc8-rt1
doesn't have it. -rc9-rt1 has it, and -rc9-rt2 has RCU preempt boosting.
I'd like to see if this is what is causing your problems.

>
> The system boots up nicely and seems to be running properly, until something
> tips it off and some commands begin to get "jammed". What seems to trigger it
> is accessing the hard disk, for instance doing something like `grep -r
> foo /var`. When it happens the desktop seems mostly responsive, but trying to
> run commands like `ls` will freeze the terminal. Other commands will succeed,
> for instance `ps aux` works as usual.
>
> Alt-SysRq-w shows more than one blocked pdflush task, as well as metalog and
> whatever commands have become "jammed" so far, like `ls`.
>
> I'll be happy to post more information, I just need to know what. I'd attach
> my .config here, but I can't access the computer from where I'm at the
> moment.

You can send me the .config off list. Also, if possible, the output of
dmesg, sysrq-t and your sysrq-w as well as (try this last because it
sometimes hangs the box hard) sysrq-L

Thanks,

-- Steve

Re: 2.6.23.8-rt11, tasks freezing

[Juuso Alasuutari]

On Wednesday 21 November 2007 16:11:48 Steven Rostedt wrote:
> On Wed, 21 Nov 2007, Juuso Alasuutari wrote:
<snip>
> > The system boots up nicely and seems to be running properly, until
> > something tips it off and some commands begin to get "jammed". What seems
> > to trigger it is accessing the hard disk, for instance doing something
> > like `grep -r foo /var`. When it happens the desktop seems mostly
> > responsive, but trying to run commands like `ls` will freeze the
> > terminal. Other commands will succeed, for instance `ps aux` works as
> > usual.
> >
> > Alt-SysRq-w shows more than one blocked pdflush task, as well as metalog
> > and whatever commands have become "jammed" so far, like `ls`.
> >
> > I'll be happy to post more information, I just need to know what. I'd
> > attach my .config here, but I can't access the computer from where I'm at
> > the moment.
>
> You can send me the .config off list. Also, if possible, the output of
> dmesg, sysrq-t and your sysrq-w as well as (try this last because it
> sometimes hangs the box hard) sysrq-L

Hi,

I sent you the output some time ago, have you had time to look at it?

Thanks,
Juuso

Re: 2.6.23.8-rt11, tasks freezing

[Steven Rostedt]

On Thu, 29 Nov 2007, Juuso Alasuutari wrote:

> On Wednesday 21 November 2007 16:11:48 Steven Rostedt wrote:
> > On Wed, 21 Nov 2007, Juuso Alasuutari wrote:
> <snip>
> > > The system boots up nicely and seems to be running properly, until
> > > something tips it off and some commands begin to get "jammed". What seems
> > > to trigger it is accessing the hard disk, for instance doing something
> > > like `grep -r foo /var`. When it happens the desktop seems mostly
> > > responsive, but trying to run commands like `ls` will freeze the
> > > terminal. Other commands will succeed, for instance `ps aux` works as
> > > usual.
> > >
> > > Alt-SysRq-w shows more than one blocked pdflush task, as well as metalog
> > > and whatever commands have become "jammed" so far, like `ls`.
> > >
> > > I'll be happy to post more information, I just need to know what. I'd
> > > attach my .config here, but I can't access the computer from where I'm at
> > > the moment.
> >
> > You can send me the .config off list. Also, if possible, the output of
> > dmesg, sysrq-t and your sysrq-w as well as (try this last because it
> > sometimes hangs the box hard) sysrq-L
>
> Hi,
>
> I sent you the output some time ago, have you had time to look at it?
>


Hi Juuso,

Sorry, several things came up as high priority, and this got pushed back.

I'll try to take a look at it this week.

-- Steve

Re: 2.6.23.8-rt11, tasks freezing

[Juuso Alasuutari]

On Thursday 29 November 2007 23:18:03 Steven Rostedt wrote:
> On Thu, 29 Nov 2007, Juuso Alasuutari wrote:
> > On Wednesday 21 November 2007 16:11:48 Steven Rostedt wrote:
<snip>
> > > You can send me the .config off list. Also, if possible, the output of
> > > dmesg, sysrq-t and your sysrq-w as well as (try this last because it
> > > sometimes hangs the box hard) sysrq-L
> >
> > Hi,
> >
> > I sent you the output some time ago, have you had time to look at it?
>
> Hi Juuso,
>
> Sorry, several things came up as high priority, and this got pushed back.
>
> I'll try to take a look at it this week.

Okay, thanks.

Juuso

Re: 2.6.23.8-rt11, tasks freezing

[Florent BOUDET]

On Wed, 21 Nov 2007, Juuso Alasuutari wrote:
 
> Hi,
> 
> I use vanilla kernels with realtime-preempt patches on a Core 2 E6600
running
> 32-bit Linux. Kernels up to 2.6.22.1-rt9 work fine, but I'm
experiencing
> strange freezing of some tasks with 2.6.23.8-rt11. (Actually all
2.6.23
> rt-kernels I've so far tried hang the same way.)
> 
> The system boots up nicely and seems to be running properly, until
something
> tips it off and some commands begin to get "jammed". What seems to
trigger it
> is accessing the hard disk, for instance doing something like `grep -r
> foo /var`. When it happens the desktop seems mostly responsive, but
trying to
> run commands like `ls` will freeze the terminal. Other commands will
succeed,
> for instance `ps aux` works as usual.
> 
> Alt-SysRq-w shows more than one blocked pdflush task, as well as
metalog and
> whatever commands have become "jammed" so far, like `ls`.
> 
> I'll be happy to post more information, I just need to know what. I'd
attach
> my .config here, but I can't access the computer from where I'm at the
> moment.
 

Hi,
 
I think I am experiencing the same symptoms using 2.6.23.9-rt12 on a
Core 2 T7400 running 32 bits Linux (National Instrument PXI 8106
controller).
The .config used is the untouched default configuration as provided in
the 2.6.23.9-rt12 kernel sources.
Has there been any solution/workaround found on this subject since the
last message in this thread?

Thank you,

Florent Boudet