Comment 3 for bug 276476

As this happens frequently I've found out that the system recovers from the freeze and resumes normal operation two to ten minutes after. However the system continues to freeze periodically after that.

Steps to reproduce:

1. Do something that causes a lot of IO operations ie. copy images, mp3's around, download Ibex cd-images from the net etc.

2. Wait until system freezes and check out dmesg from terminal (if you it opens) and you'll see something like this:

[ 9309.344503] INFO: task pdflush:17487 blocked for more than 120 seconds.
[ 9309.344505] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 9309.344508] pdflush D 0000000000000001 0 17487 2
[ 9309.344513] ffff8800b2ce14e0 0000000000000046 00000000000256b3 ffffffff803a7def
[ 9309.344518] ffffffff807a5400 ffffffff807a5400 ffffffff807a5400 ffffffff807a5400
[ 9309.344524] ffffffff807a5400 ffffffff807a5400 ffffffff807a5400 ffffffff807a5400
[ 9309.344528] Call Trace:
[ 9309.344534] [<ffffffff803a7def>] ? __up_read+0x8f/0xb0
[ 9309.344538] [<ffffffff80500d65>] schedule_timeout+0x95/0xd0
[ 9309.344560] [<ffffffffa0af9037>] ? xfs_bmap_add_extent+0x237/0x420 [xfs]
[ 9309.344565] [<ffffffff805017e6>] __down+0x76/0xc0
[ 9309.344569] [<ffffffff8026bddc>] down+0x4c/0x50
[ 9309.344590] [<ffffffffa0b3ee23>] xfs_buf_lock+0x23/0x60 [xfs]
[ 9309.344612] [<ffffffffa0b2b9e2>] xfs_getsb+0x22/0x50 [xfs]
[ 9309.344634] [<ffffffffa0b3269a>] xfs_trans_getsb+0x5a/0xa0 [xfs]
[ 9309.344656] [<ffffffffa0b30d90>] xfs_trans_apply_sb_deltas+0x20/0x320 [xfs]
[ 9309.344678] [<ffffffffa0b311ab>] _xfs_trans_commit+0x11b/0x3f0 [xfs]
[ 9309.344700] [<ffffffffa0b227de>] ? xlog_space_left+0xe/0x90 [xfs]
[ 9309.344721] [<ffffffffa0af65d1>] ? xfs_bmap_finish+0x21/0x1a0 [xfs]
[ 9309.344744] [<ffffffffa0b1f518>] xfs_iomap_write_allocate+0x288/0x3e0 [xfs]
[ 9309.344767] [<ffffffffa0b20356>] xfs_iomap+0x2d6/0x310 [xfs]
[ 9309.344773] [<ffffffff80395f66>] ? blk_rq_map_sg+0x16/0x2d0
[ 9309.344793] [<ffffffffa0b3b15b>] xfs_map_blocks+0x3b/0x90 [xfs]
[ 9309.344799] [<ffffffff803b36c6>] ? swiotlb_map_sg_attrs+0x56/0x160
[ 9309.344819] [<ffffffffa0b3c3eb>] xfs_page_state_convert+0x2fb/0x760 [xfs]
[ 9309.344838] [<ffffffffa010338c>] ? ahci_qc_issue+0xc/0xe0 [ahci]
[ 9309.344844] [<ffffffff803a6d30>] ? radix_tree_gang_lookup_tag_slot+0xc0/0xe0
[ 9309.344849] [<ffffffff8038fa24>] ? elv_next_request+0x164/0x290
[ 9309.344870] [<ffffffffa0b3c9b1>] xfs_vm_writepage+0x71/0x120 [xfs]
[ 9309.344875] [<ffffffff802bbeaa>] ? __dec_zone_page_state+0x2a/0x30
[ 9309.344879] [<ffffffff802b4407>] __writepage+0x17/0x50
[ 9309.344883] [<ffffffff802b568d>] write_cache_pages+0x2bd/0x420
[ 9309.344887] [<ffffffff802b43f0>] ? __writepage+0x0/0x50
[ 9309.344890] [<ffffffff802aefab>] ? mempool_alloc+0x5b/0x140
[ 9309.344896] [<ffffffff802b5814>] generic_writepages+0x24/0x30
[ 9309.344916] [<ffffffffa0b3b50c>] xfs_vm_writepages+0x5c/0x80 [xfs]
[ 9309.344921] [<ffffffff802b584d>] do_writepages+0x2d/0x50
[ 9309.344925] [<ffffffff8030ea3b>] __sync_single_inode+0x6b/0x2f0
[ 9309.344930] [<ffffffff8030ed18>] __writeback_single_inode+0x58/0x1b0
[ 9309.344933] [<ffffffff8023bae2>] ? update_curr+0x62/0xd0
[ 9309.344937] [<ffffffff803a7905>] ? rb_erase+0xe5/0x170
[ 9309.344942] [<ffffffff8030f2d4>] generic_sync_sb_inodes+0x314/0x490
[ 9309.344945] [<ffffffff8030f702>] writeback_inodes+0x62/0x100
[ 9309.344950] [<ffffffff802b4d18>] background_writeout+0xb8/0xf0
[ 9309.344954] [<ffffffff802b607e>] __pdflush+0x13e/0x220
[ 9309.344958] [<ffffffff802b61bb>] pdflush+0x5b/0x70
[ 9309.344962] [<ffffffff802b4c60>] ? background_writeout+0x0/0xf0
[ 9309.344965] [<ffffffff802b6160>] ? pdflush+0x0/0x70
[ 9309.344968] [<ffffffff80266c1e>] kthread+0x4e/0x90
[ 9309.344972] [<ffffffff80213c99>] child_rip+0xa/0x11
[ 9309.344976] [<ffffffff80266bd0>] ? kthread+0x0/0x90
[ 9309.344978] [<ffffffff80213c8f>] ? child_rip+0x0/0x11
[ 9309.344981]

dmesg show nothing more than things resume to normal.