2.6.23-rt2

2.6.23-rt2

[Steven Rostedt]

We are pleased to announce the 2.6.23-rt2 tree, which can be
downloaded from the location:

 http://www.kernel.org/pub/linux/kernel/projects/rt/

Changes since 2.6.23-rt1

  - Improved RT balancing (Steven Rostedt
                 with thanks to Gregory Haskins for some ideas)

  - plist debug fix (Arnaldo Carvalho de Melo)

  - seqlock irq fix (Daniel Walker)

  - slab NUMA freeing (Andi Kleen)


to build a 2.6.23-rt2 tree, the following patches should be applied:

  http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.23.tar.bz2
  http://www.kernel.org/pub/linux/kernel/projects/rt/patch-2.6.23-rt2.bz2

The broken out patches are also available.

-- Steve

[2.6.23-rt3] NMI watchdog trace of deadlock

[Mike Galbraith]

Greetings,

For quite a while now, RT kernels have been locking up on me
occasionally while my back is turned.  Yesterday, the little bugger
finally pounced while my serial console box was up and waiting.

[10138.162953] WARNING: at arch/i386/kernel/smp.c:581 native_smp_call_function_mask()
[10138.170583]  [<c01051da>] show_trace_log_lvl+0x1a/0x30
[10138.175796]  [<c0105de3>] show_trace+0x12/0x14
[10138.180291]  [<c0105dfb>] dump_stack+0x16/0x18
[10138.184769]  [<c011609f>] native_smp_call_function_mask+0x138/0x13d
[10138.191117]  [<c0117606>] smp_call_function+0x1e/0x24
[10138.196210]  [<c012f85c>] on_each_cpu+0x25/0x50
[10138.200807]  [<c0115c74>] flush_tlb_all+0x1e/0x20
[10138.205553]  [<c016caaf>] kmap_high+0x1b6/0x417
[10138.210118]  [<c011ec88>] kmap+0x4d/0x4f
[10138.214102]  [<c026a9d8>] ntfs_end_buffer_async_read+0x228/0x2f9
[10138.220163]  [<c01a0e9e>] end_bio_bh_io_sync+0x26/0x3f
[10138.225352]  [<c01a2b09>] bio_endio+0x42/0x6d
[10138.229769]  [<c02c2a08>] __end_that_request_first+0x115/0x4ac
[10138.235682]  [<c02c2da7>] end_that_request_chunk+0x8/0xa
[10138.241052]  [<c0365943>] ide_end_request+0x55/0x10a
[10138.246058]  [<c036dae3>] ide_dma_intr+0x6f/0xac
[10138.250727]  [<c0366d83>] ide_intr+0x93/0x1e0
[10138.255125]  [<c015afb4>] handle_IRQ_event+0x5c/0xc9
[10138.260113]  [<c015bcfd>] do_irqd+0x1fc/0x2ef
[10138.264514]  [<c013cdb2>] kthread+0x39/0x5b
[10138.268740]  [<c0104e33>] kernel_thread_helper+0x7/0x14
[10138.274006]  =======================
[10149.157158] NMI watchdog detected lockup on CPU#0 (5/5)
[10149.162445] 
[10149.163943] Pid: 880, comm:               IRQ-14
[10149.168612] EIP: 0060:[<c04c1ccf>] CPU: 0
[10149.172666] EIP is at __spin_lock+0x16/0x1f
[10149.176909]  EFLAGS: 00000086    Not tainted  (2.6.23.1-rt3-smp #117)
[10149.183403] EAX: c0640b00 EBX: 00000003 ECX: c060fc24 EDX: dff2b000
[10149.189751] ESI: c01161be EDI: 00000000 EBP: dff2bce4 DS: 007b ES: 007b FS: 00d8
[10149.197252] CR0: 8005003b CR2: b658217b CR3: 01a71000 CR4: 000006d0
[10149.203574] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[10149.209896] DR6: ffff0ff0 DR7: 00000400
[10149.213766]  [<c01051da>] show_trace_log_lvl+0x1a/0x30
[10149.218979]  [<c0105de3>] show_trace+0x12/0x14
[10149.223440]  [<c0102b27>] show_regs+0x1c4/0x1cb
[10149.228021]  [<c0118978>] nmi_watchdog_tick+0x1a5/0x226
[10149.233321]  [<c01062fd>] do_nmi+0x85/0x25f
[10149.237547]  [<c04c229b>] nmi_stack_correct+0x26/0x2b
[10149.242649]  [<c0115f8c>] native_smp_call_function_mask+0x25/0x13d
[10149.248893]  [<c0117606>] smp_call_function+0x1e/0x24
[10149.254002]  [<c012f85c>] on_each_cpu+0x25/0x50
[10149.258575]  [<c0115c74>] flush_tlb_all+0x1e/0x20
[10149.263331]  [<c016caaf>] kmap_high+0x1b6/0x417
[10149.267919]  [<c011ec88>] kmap+0x4d/0x4f
[10149.271878]  [<c026a9d8>] ntfs_end_buffer_async_read+0x228/0x2f9
[10149.277949]  [<c01a0e9e>] end_bio_bh_io_sync+0x26/0x3f
[10149.283120]  [<c01a2b09>] bio_endio+0x42/0x6d
[10149.287527]  [<c02c2a08>] __end_that_request_first+0x115/0x4ac
[10149.293417]  [<c02c2da7>] end_that_request_chunk+0x8/0xa
[10149.298785]  [<c0365943>] ide_end_request+0x55/0x10a
[10149.303816]  [<c036dae3>] ide_dma_intr+0x6f/0xac
[10149.308521]  [<c0366d83>] ide_intr+0x93/0x1e0
[10149.312927]  [<c015afb4>] handle_IRQ_event+0x5c/0xc9
[10149.317977]  [<c015bcfd>] do_irqd+0x1fc/0x2ef
[10149.322343]  [<c013cdb2>] kthread+0x39/0x5b
[10149.326568]  [<c0104e33>] kernel_thread_helper+0x7/0x14
[10149.331843]  =======================
[10150.156614] NMI show regs on CPU#1:
[10150.156616] NMI watchdog running again ...
[10150.164292] apic_timer_irqs: 3289514
[10150.167894] 
[10150.169403] Pid: 6317, comm:               smpppd
[10150.174157] EIP: 0060:[<c0115ffe>] CPU: 1
[10150.178203] EIP is at native_smp_call_function_mask+0x97/0x13d
[10150.184074]  EFLAGS: 00200202    Not tainted  (2.6.23.1-rt3-smp #117)
[10150.190594] EAX: ffffb300 EBX: 00000001 ECX: 00000001 EDX: 000008fb
[10150.196899] ESI: 00000001 EDI: 00000000 EBP: f69a4c6c DS: 007b ES: 007b FS: 00d8
[10150.204339] CR0: 8005003b CR2: b7f91000 CR3: 37221000 CR4: 000006d0
[10150.210636] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[10150.216940] DR6: ffff0ff0 DR7: 00000400
[10150.220784]  [<c01051da>] show_trace_log_lvl+0x1a/0x30
[10150.225980]  [<c0105de3>] show_trace+0x12/0x14
[10150.230502]  [<c0102b27>] show_regs+0x1c4/0x1cb
[10150.235084]  [<c01187c2>] irq_show_regs_callback+0x63/0x74
[10150.240668]  [<c011885a>] nmi_watchdog_tick+0x87/0x226
[10150.245856]  [<c01062fd>] do_nmi+0x85/0x25f
[10150.250074]  [<c04c229b>] nmi_stack_correct+0x26/0x2b
[10150.255201]  [<c0117606>] smp_call_function+0x1e/0x24
[10150.260336]  [<c012f85c>] on_each_cpu+0x25/0x50
[10150.264908]  [<c0115c74>] flush_tlb_all+0x1e/0x20
[10150.269706]  [<c016caaf>] kmap_high+0x1b6/0x417
[10150.274297]  [<c011ec88>] kmap+0x4d/0x4f
[10150.278289]  [<c0165b94>] get_page_from_freelist+0x247/0x32e
[10150.284023]  [<c0165cd9>] __alloc_pages+0x5e/0x2da
[10150.288863]  [<c016ec4e>] handle_mm_fault+0x368/0x62f
[10150.293991]  [<c011de93>] do_page_fault+0x180/0x61d
[10150.298919]  [<c04c21f2>] error_code+0x72/0x78
[10150.303422]  [<c02d5024>] copy_to_user+0x2a/0x36
[10150.308089]  [<c0199845>] seq_read+0x19b/0x296
[10150.312593]  [<c01b4dcb>] proc_reg_read+0x57/0x78
[10150.317374]  [<c018116f>] vfs_read+0x89/0x11d
[10150.321791]  [<c01815e1>] sys_read+0x3d/0x64
[10150.326095]  [<c0104242>] syscall_call+0x7/0xb
[10150.330608]  =======================

Re: [2.6.23-rt3] NMI watchdog trace of deadlock

[Nick Piggin]

On Saturday 27 October 2007 15:21, Mike Galbraith wrote:
> Greetings,
>
> For quite a while now, RT kernels have been locking up on me
> occasionally while my back is turned.  Yesterday, the little bugger
> finally pounced while my serial console box was up and waiting.
>
> [10138.162953] WARNING: at arch/i386/kernel/smp.c:581
> native_smp_call_function_mask() [10138.170583]  [<c01051da>]
> show_trace_log_lvl+0x1a/0x30
> [10138.175796]  [<c0105de3>] show_trace+0x12/0x14
> [10138.180291]  [<c0105dfb>] dump_stack+0x16/0x18
> [10138.184769]  [<c011609f>] native_smp_call_function_mask+0x138/0x13d
> [10138.191117]  [<c0117606>] smp_call_function+0x1e/0x24
> [10138.196210]  [<c012f85c>] on_each_cpu+0x25/0x50
> [10138.200807]  [<c0115c74>] flush_tlb_all+0x1e/0x20
> [10138.205553]  [<c016caaf>] kmap_high+0x1b6/0x417
> [10138.210118]  [<c011ec88>] kmap+0x4d/0x4f
> [10138.214102]  [<c026a9d8>] ntfs_end_buffer_async_read+0x228/0x2f9
> [10138.220163]  [<c01a0e9e>] end_bio_bh_io_sync+0x26/0x3f
> [10138.225352]  [<c01a2b09>] bio_endio+0x42/0x6d
> [10138.229769]  [<c02c2a08>] __end_that_request_first+0x115/0x4ac
> [10138.235682]  [<c02c2da7>] end_that_request_chunk+0x8/0xa
> [10138.241052]  [<c0365943>] ide_end_request+0x55/0x10a
> [10138.246058]  [<c036dae3>] ide_dma_intr+0x6f/0xac
> [10138.250727]  [<c0366d83>] ide_intr+0x93/0x1e0
> [10138.255125]  [<c015afb4>] handle_IRQ_event+0x5c/0xc9

Looks like ntfs is kmap()ing from interrupt context. Should
be using kmap_atomic instead, I think.

But the ntfs code I have seems to do just that...

Re: [2.6.23-rt3] NMI watchdog trace of deadlock

[Mike Galbraith]

On Sat, 2007-10-27 at 19:15 +1000, Nick Piggin wrote:
> On Saturday 27 October 2007 15:21, Mike Galbraith wrote:
> > Greetings,
> >
> > For quite a while now, RT kernels have been locking up on me
> > occasionally while my back is turned.  Yesterday, the little bugger
> > finally pounced while my serial console box was up and waiting.
> >
> > [10138.162953] WARNING: at arch/i386/kernel/smp.c:581
> > native_smp_call_function_mask() [10138.170583]  [<c01051da>]
> > show_trace_log_lvl+0x1a/0x30
> > [10138.175796]  [<c0105de3>] show_trace+0x12/0x14
> > [10138.180291]  [<c0105dfb>] dump_stack+0x16/0x18
> > [10138.184769]  [<c011609f>] native_smp_call_function_mask+0x138/0x13d
> > [10138.191117]  [<c0117606>] smp_call_function+0x1e/0x24
> > [10138.196210]  [<c012f85c>] on_each_cpu+0x25/0x50
> > [10138.200807]  [<c0115c74>] flush_tlb_all+0x1e/0x20
> > [10138.205553]  [<c016caaf>] kmap_high+0x1b6/0x417
> > [10138.210118]  [<c011ec88>] kmap+0x4d/0x4f
> > [10138.214102]  [<c026a9d8>] ntfs_end_buffer_async_read+0x228/0x2f9
> > [10138.220163]  [<c01a0e9e>] end_bio_bh_io_sync+0x26/0x3f
> > [10138.225352]  [<c01a2b09>] bio_endio+0x42/0x6d
> > [10138.229769]  [<c02c2a08>] __end_that_request_first+0x115/0x4ac
> > [10138.235682]  [<c02c2da7>] end_that_request_chunk+0x8/0xa
> > [10138.241052]  [<c0365943>] ide_end_request+0x55/0x10a
> > [10138.246058]  [<c036dae3>] ide_dma_intr+0x6f/0xac
> > [10138.250727]  [<c0366d83>] ide_intr+0x93/0x1e0
> > [10138.255125]  [<c015afb4>] handle_IRQ_event+0x5c/0xc9
> 
> Looks like ntfs is kmap()ing from interrupt context. Should
> be using kmap_atomic instead, I think.
> 
> But the ntfs code I have seems to do just that...

The ntfs code does use kmap_atomic(), bit RT turns that into a wrapper
for kmap().  I fed it a local_irq_enable(), and am waiting for it to
tell me why that was stoopid ;-)

	thanks,

	-Mike

Re: [2.6.23-rt3] NMI watchdog trace of deadlock

[Ingo Molnar]

* Nick Piggin <nickpiggin@yahoo.com.au> wrote:

> > [10138.175796]  [<c0105de3>] show_trace+0x12/0x14
> > [10138.180291]  [<c0105dfb>] dump_stack+0x16/0x18
> > [10138.184769]  [<c011609f>] native_smp_call_function_mask+0x138/0x13d
> > [10138.191117]  [<c0117606>] smp_call_function+0x1e/0x24
> > [10138.196210]  [<c012f85c>] on_each_cpu+0x25/0x50
> > [10138.200807]  [<c0115c74>] flush_tlb_all+0x1e/0x20
> > [10138.205553]  [<c016caaf>] kmap_high+0x1b6/0x417
> > [10138.210118]  [<c011ec88>] kmap+0x4d/0x4f
> > [10138.214102]  [<c026a9d8>] ntfs_end_buffer_async_read+0x228/0x2f9
> > [10138.220163]  [<c01a0e9e>] end_bio_bh_io_sync+0x26/0x3f
> > [10138.225352]  [<c01a2b09>] bio_endio+0x42/0x6d
> > [10138.229769]  [<c02c2a08>] __end_that_request_first+0x115/0x4ac
> > [10138.235682]  [<c02c2da7>] end_that_request_chunk+0x8/0xa
> > [10138.241052]  [<c0365943>] ide_end_request+0x55/0x10a
> > [10138.246058]  [<c036dae3>] ide_dma_intr+0x6f/0xac
> > [10138.250727]  [<c0366d83>] ide_intr+0x93/0x1e0
> > [10138.255125]  [<c015afb4>] handle_IRQ_event+0x5c/0xc9
> 
> Looks like ntfs is kmap()ing from interrupt context. Should be using 
> kmap_atomic instead, I think.

it's not atomic interrupt context but irq thread context - and -rt 
remaps kmap_atomic() to kmap() internally.

the problem seems to be what Mike's patch works around: fiddling with 
irq flags in the ntfs code. That fiddling seems quite unnecessary at 
first sight.

	Ingo

Re: [2.6.23-rt3] NMI watchdog trace of deadlock

[Jaswinder Singh]

Hello Ingo,

On 10/27/07, Ingo Molnar <mingo@elte.hu> wrote:
>
> it's not atomic interrupt context but irq thread context - and -rt
> remaps kmap_atomic() to kmap() internally.
>
> the problem seems to be what Mike's patch works around: fiddling with
> irq flags in the ntfs code. That fiddling seems quite unnecessary at
> first sight.
>

Is this a nice idea to go inside device drivers and filesystem and
make changes in kernel source code to enable RT.

RT related change should be in header files, so that we don't need to
make changes for drivers or filesystem source files.

And when user will disable RT then these patches will again make problems.

We need to find some better alternative.

Thank you,

Jaswinder Singh.

Re: [2.6.23-rt3] NMI watchdog trace of deadlock

[Steven Rostedt]

--

On Sat, 27 Oct 2007, Jaswinder Singh wrote:

> Hello Ingo,
>
> On 10/27/07, Ingo Molnar <mingo@elte.hu> wrote:
> >
> > it's not atomic interrupt context but irq thread context - and -rt
> > remaps kmap_atomic() to kmap() internally.
> >
> > the problem seems to be what Mike's patch works around: fiddling with
> > irq flags in the ntfs code. That fiddling seems quite unnecessary at
> > first sight.
> >
>
> Is this a nice idea to go inside device drivers and filesystem and
> make changes in kernel source code to enable RT.

Actually the question is, is it a nice idea for drivers to disable
interrupts for no obvious reason. I'm sure you have a reason, but it's not
obvious to me why. What does it protect? Is it SMP safe?

When tuning a RT system for the customer, the first thing we recommend is
to check to make sure all the drivers in use do not disable interrupts.

>
> RT related change should be in header files, so that we don't need to
> make changes for drivers or filesystem source files.
>
> And when user will disable RT then these patches will again make problems.
>
> We need to find some better alternative.

We do have the local_irq_save_nort that Mike has posted.  This is a simple
wrapper around local_irq_save that enables it when RT is not configured,
and is a nop when RT is configured.

Thanks,

-- Steve

Re: [2.6.23-rt3] NMI watchdog trace of deadlock

[Mike Galbraith]

On Sat, 2007-10-27 at 11:44 +0200, Ingo Molnar wrote:
> * Nick Piggin <nickpiggin@yahoo.com.au> wrote:
> 
> > > [10138.175796]  [<c0105de3>] show_trace+0x12/0x14
> > > [10138.180291]  [<c0105dfb>] dump_stack+0x16/0x18
> > > [10138.184769]  [<c011609f>] native_smp_call_function_mask+0x138/0x13d
> > > [10138.191117]  [<c0117606>] smp_call_function+0x1e/0x24
> > > [10138.196210]  [<c012f85c>] on_each_cpu+0x25/0x50
> > > [10138.200807]  [<c0115c74>] flush_tlb_all+0x1e/0x20
> > > [10138.205553]  [<c016caaf>] kmap_high+0x1b6/0x417
> > > [10138.210118]  [<c011ec88>] kmap+0x4d/0x4f
> > > [10138.214102]  [<c026a9d8>] ntfs_end_buffer_async_read+0x228/0x2f9
> > > [10138.220163]  [<c01a0e9e>] end_bio_bh_io_sync+0x26/0x3f
> > > [10138.225352]  [<c01a2b09>] bio_endio+0x42/0x6d
> > > [10138.229769]  [<c02c2a08>] __end_that_request_first+0x115/0x4ac
> > > [10138.235682]  [<c02c2da7>] end_that_request_chunk+0x8/0xa
> > > [10138.241052]  [<c0365943>] ide_end_request+0x55/0x10a
> > > [10138.246058]  [<c036dae3>] ide_dma_intr+0x6f/0xac
> > > [10138.250727]  [<c0366d83>] ide_intr+0x93/0x1e0
> > > [10138.255125]  [<c015afb4>] handle_IRQ_event+0x5c/0xc9
> > 
> > Looks like ntfs is kmap()ing from interrupt context. Should be using 
> > kmap_atomic instead, I think.
> 
> it's not atomic interrupt context but irq thread context - and -rt 
> remaps kmap_atomic() to kmap() internally.

Hm.  Looking at the change to mm/bounce.c, perhaps I should do this
instead?

--- ./fs/ntfs/aops.c.org	2007-10-27 10:16:40.000000000 +0200
+++ ./fs/ntfs/aops.c	2007-10-27 12:11:07.000000000 +0200
@@ -139,13 +139,13 @@ static void ntfs_end_buffer_async_read(s
 		recs = PAGE_CACHE_SIZE / rec_size;
 		/* Should have been verified before we got here... */
 		BUG_ON(!recs);
-		local_irq_save(flags);
+		local_irq_save_nort(flags);
 		kaddr = kmap_atomic(page, KM_BIO_SRC_IRQ);
 		for (i = 0; i < recs; i++)
 			post_read_mst_fixup((NTFS_RECORD*)(kaddr +
 					i * rec_size), rec_size);
 		kunmap_atomic(kaddr, KM_BIO_SRC_IRQ);
-		local_irq_restore(flags);
+		local_irq_restore_nort(flags);
 		flush_dcache_page(page);
 		if (likely(page_uptodate && !PageError(page)))
 			SetPageUptodate(page);

Re: [2.6.23-rt3] NMI watchdog trace of deadlock

[Ingo Molnar]

* Mike Galbraith <efault@gmx.de> wrote:

> > it's not atomic interrupt context but irq thread context - and -rt 
> > remaps kmap_atomic() to kmap() internally.
> 
> Hm.  Looking at the change to mm/bounce.c, perhaps I should do this 
> instead?

yeah, this looks better.

	Ingo

Re: [2.6.23-rt3] NMI watchdog trace of deadlock

[Steven Rostedt]

--
On Sat, 27 Oct 2007, Mike Galbraith wrote:
>
> Hm.  Looking at the change to mm/bounce.c, perhaps I should do this
> instead?
>
> --- ./fs/ntfs/aops.c.org	2007-10-27 10:16:40.000000000 +0200
> +++ ./fs/ntfs/aops.c	2007-10-27 12:11:07.000000000 +0200
> @@ -139,13 +139,13 @@ static void ntfs_end_buffer_async_read(s
>  		recs = PAGE_CACHE_SIZE / rec_size;
>  		/* Should have been verified before we got here... */
>  		BUG_ON(!recs);
> -		local_irq_save(flags);
> +		local_irq_save_nort(flags);
>  		kaddr = kmap_atomic(page, KM_BIO_SRC_IRQ);
>  		for (i = 0; i < recs; i++)
>  			post_read_mst_fixup((NTFS_RECORD*)(kaddr +
>  					i * rec_size), rec_size);
>  		kunmap_atomic(kaddr, KM_BIO_SRC_IRQ);
> -		local_irq_restore(flags);
> +		local_irq_restore_nort(flags);
>  		flush_dcache_page(page);
>  		if (likely(page_uptodate && !PageError(page)))
>  			SetPageUptodate(page);
>

Thanks, applied.

-- Steve

Re: [2.6.23-rt3] NMI watchdog trace of deadlock

[Mike Galbraith]

On Sat, 2007-10-27 at 07:21 +0200, Mike Galbraith wrote:
> Greetings,
> 
> For quite a while now, RT kernels have been locking up on me
> occasionally while my back is turned.  Yesterday, the little bugger
> finally pounced while my serial console box was up and waiting.
> 
> [10138.162953] WARNING: at arch/i386/kernel/smp.c:581 native_smp_call_function_mask()
> [10138.170583]  [<c01051da>] show_trace_log_lvl+0x1a/0x30
> [10138.175796]  [<c0105de3>] show_trace+0x12/0x14
> [10138.180291]  [<c0105dfb>] dump_stack+0x16/0x18
> [10138.184769]  [<c011609f>] native_smp_call_function_mask+0x138/0x13d
> [10138.191117]  [<c0117606>] smp_call_function+0x1e/0x24
> [10138.196210]  [<c012f85c>] on_each_cpu+0x25/0x50
> [10138.200807]  [<c0115c74>] flush_tlb_all+0x1e/0x20
> [10138.205553]  [<c016caaf>] kmap_high+0x1b6/0x417
> [10138.210118]  [<c011ec88>] kmap+0x4d/0x4f
> [10138.214102]  [<c026a9d8>] ntfs_end_buffer_async_read+0x228/0x2f9
> [10138.220163]  [<c01a0e9e>] end_bio_bh_io_sync+0x26/0x3f
> [10138.225352]  [<c01a2b09>] bio_endio+0x42/0x6d
> [10138.229769]  [<c02c2a08>] __end_that_request_first+0x115/0x4ac
> [10138.235682]  [<c02c2da7>] end_that_request_chunk+0x8/0xa
> [10138.241052]  [<c0365943>] ide_end_request+0x55/0x10a
> [10138.246058]  [<c036dae3>] ide_dma_intr+0x6f/0xac
> [10138.250727]  [<c0366d83>] ide_intr+0x93/0x1e0
> [10138.255125]  [<c015afb4>] handle_IRQ_event+0x5c/0xc9
> [10138.260113]  [<c015bcfd>] do_irqd+0x1fc/0x2ef
> [10138.264514]  [<c013cdb2>] kthread+0x39/0x5b
> [10138.268740]  [<c0104e33>] kernel_thread_helper+0x7/0x14
> [10138.274006]  =======================

(box may recommend that i go figure out why interrupts are disabled
instead;)

--- ./fs/ntfs/aops.c.org	2007-10-27 10:16:40.000000000 +0200
+++ ./fs/ntfs/aops.c	2007-10-27 10:30:52.000000000 +0200
@@ -140,6 +140,7 @@ static void ntfs_end_buffer_async_read(s
 		/* Should have been verified before we got here... */
 		BUG_ON(!recs);
 		local_irq_save(flags);
+		local_irq_enable();
 		kaddr = kmap_atomic(page, KM_BIO_SRC_IRQ);
 		for (i = 0; i < recs; i++)
 			post_read_mst_fixup((NTFS_RECORD*)(kaddr +