Bug 9441

Here is a trace for good and bad pdflush processes:

Nov 22 16:35:09 oxygene kernel:  =======================
Nov 22 16:35:09 oxygene kernel: pdflush       S c014fe4e     0   150 2
Nov 22 16:35:09 oxygene kernel:        00000000 00000046 00000000 c014fe4e f7c30fa4 c014f9c6 f7ce8560 f7ce869c
Nov 22 16:35:09 oxygene kernel:        c201e100 00000001 fffffffc 00000002 00000000 00000000 00000000 00000000
Nov 22 16:35:09 oxygene kernel:        00000021 f7c30fc8 c014fe4e 00000000 00000000 c014ff09 00000202 f7ce8560
Nov 22 16:35:09 oxygene kernel: Call Trace:
Nov 22 16:35:09 oxygene kernel:  [pdflush+0/434] pdflush+0x0/0x1b2
Nov 22 16:35:09 oxygene kernel:  [background_writeout+125/173] background_writeout+0x7d/0xad
Nov 22 16:35:09 oxygene kernel:  [pdflush+0/434] pdflush+0x0/0x1b2
Nov 22 16:35:09 oxygene kernel:  [pdflush+187/434] pdflush+0xbb/0x1b2
Nov 22 16:35:09 oxygene kernel:  [kthread+56/96] kthread+0x38/0x60
Nov 22 16:35:09 oxygene kernel:  [kthread+0/96] kthread+0x0/0x60
Nov 22 16:35:09 oxygene kernel:  [kernel_thread_helper+7/16] kernel_thread_helper+0x7/0x10
Nov 22 16:35:09 oxygene kernel:  =======================
Nov 22 16:35:09 oxygene kernel: pdflush       D f7c3aef4     0   151 2
Nov 22 16:35:09 oxygene kernel:        0b83b953 00000046 00000002 f7c3aef4 f7c3aeec 00000000 f7ce8ac0 f7ce8bfc
Nov 22 16:35:09 oxygene kernel:        c201e100 00000001 f7c3af18 0b83b9cc f7c3af18 00000003 00000000 00000001
Nov 22 16:35:09 oxygene kernel:        00000000 f7c3af18 0b83b9cc f7c3af70 00000000 c027ddb7 f781e000 c010490c
Nov 22 16:35:09 oxygene kernel: Call Trace:
Nov 22 16:35:09 oxygene kernel:  [schedule_timeout+112/141] schedule_timeout+0x70/0x8d
Nov 22 16:35:09 oxygene kernel:  [apic_timer_interrupt+40/48] apic_timer_interrupt+0x28/0x30
Nov 22 16:35:09 oxygene kernel:  [process_timeout+0/5] process_timeout+0x0/0x5
Nov 22 16:35:09 oxygene kernel:  [schedule_timeout+107/141] schedule_timeout+0x6b/0x8d
Nov 22 16:35:09 oxygene kernel:  [io_schedule_timeout+27/36] io_schedule_timeout+0x1b/0x24
Nov 22 16:35:09 oxygene kernel:  [congestion_wait+80/100] congestion_wait+0x50/0x64
Nov 22 16:35:09 oxygene kernel:  [autoremove_wake_function+0/53] autoremove_wake_function+0x0/0x35
Nov 22 16:35:09 oxygene kernel:  [pdflush+0/434] pdflush+0x0/0x1b2
Nov 22 16:35:09 oxygene kernel:  [wb_kupdate+152/219] wb_kupdate+0x98/0xdb
Nov 22 16:35:09 oxygene kernel:  [pdflush+282/434] pdflush+0x11a/0x1b2
Nov 22 16:35:09 oxygene kernel:  [wb_kupdate+0/219] wb_kupdate+0x0/0xdb
Nov 22 16:35:09 oxygene kernel:  [kthread+56/96] kthread+0x38/0x60
Nov 22 16:35:09 oxygene kernel:  [kthread+0/96] kthread+0x0/0x60
Nov 22 16:35:09 oxygene kernel:  [kernel_thread_helper+7/16] kernel_thread_helper+0x7/0x10
Nov 22 16:35:09 oxygene kernel:  =======================

The same happens here on my laptop:
pdflush       D c10458e0     0 18280      2
       00000000 00000046 c138a080 c10458e0 c156e4a0 c11b3e20 c0494eb0 c0497940 
       f7403000 f7403140 c17fb940 00000000 d89d3f14 0040ca85 d89d3f14 00000202 
       c012afd7 00000000 00000202 d89d3f14 0040ca85 d89d3f6c 00000000 c0353878 
Call Trace:
 [<c012afd7>] __mod_timer+0x9d/0xa7
 [<c0353878>] schedule_timeout+0x70/0x8d
 [<c010672c>] do_IRQ+0x5c/0x70
 [<c012abea>] process_timeout+0x0/0x5
 [<c0353873>] schedule_timeout+0x6b/0x8d
 [<c0353739>] io_schedule_timeout+0x1b/0x24
 [<c01542d3>] congestion_wait+0x51/0x65
 [<c0133a74>] autoremove_wake_function+0x0/0x33
 [<c015027c>] pdflush+0x0/0x1ac
 [<c014fee0>] wb_kupdate+0x99/0xde
 [<c015027c>] pdflush+0x0/0x1ac
 [<c015038f>] pdflush+0x113/0x1ac
 [<c014fe47>] wb_kupdate+0x0/0xde
 [<c01339a5>] kthread+0x38/0x5f
 [<c013396d>] kthread+0x0/0x5f
 [<c0104b97>] kernel_thread_helper+0x7/0x10

2.6.24-rc3, but with prior rcs, too.

I can make it happen quite easy by calling some svn update of big repositories.

Manually calling sync from command line will put pdflush back into S state, but after a while it will switch to D again.

My kernel: 2.6.24-rc2
My CPU:    Intel Core 2 Duo (only one pdflush is stuck)
My disk:   SATA -> LVM PV -> LVM VG -> LVM LV -> DM-crypt -> root partition
                                    -> LVM LV -> DM-crypt -> swap partition

It looks like this is the same issue as in Bug #9291.


*** This bug has been marked as a duplicate of bug 9291 ***