On Sat, Mar 31, 2012 at 12:35 AM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > On Sat, 31 Mar 2012 00:23:30 +0200 > Sasha Levin <levinsasha928@xxxxxxxxx> wrote: > >> Hi all, >> >> I saw the following inside a KVM guest, this is the first time I >> observed this hang and it seems to have started with today's >> (20120330) -next. >> >> [ 3122.093136] INFO: task trinity:17328 blocked for more than 120 seconds. >> [ 3122.093807] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" >> disables this message. >> [ 3122.095237] trinity D ffff8800703284d8 5648 17328 3101 0x00000004 >> [ 3122.096543] ffff8800064cfb08 0000000000000082 ffff8800064cfab8 >> ffffffff8107d346 >> [ 3122.098087] ffff8800064cffd8 00000000001d4580 ffff8800064ce010 >> 00000000001d4580 >> [ 3122.099447] 00000000001d4580 00000000001d4580 ffff8800064cffd8 >> 00000000001d4580 >> [ 3122.100607] Call Trace: >> [ 3122.100983] [<ffffffff8107d346>] ? kvm_clock_read+0x46/0x80 >> [ 3122.101950] [<ffffffff81176260>] ? __lock_page+0x70/0x70 >> [ 3122.102761] [<ffffffff827063d4>] schedule+0x24/0x70 >> [ 3122.103576] [<ffffffff827064a7>] io_schedule+0x87/0xd0 >> [ 3122.104371] [<ffffffff81176269>] sleep_on_page+0x9/0x10 >> [ 3122.105179] [<ffffffff82704152>] __wait_on_bit_lock+0x52/0xb0 >> [ 3122.106042] [<ffffffff81176252>] __lock_page+0x62/0x70 >> [ 3122.106811] [<ffffffff810d78f0>] ? autoremove_wake_function+0x40/0x40 >> [ 3122.107450] [<ffffffff811cc2f9>] lock_page+0x39/0x40 >> [ 3122.107976] [<ffffffff811cd294>] __unmap_and_move+0x274/0x280 >> [ 3122.108848] [<ffffffff81899061>] ? list_del+0x11/0x40 >> [ 3122.109385] [<ffffffff811cd32d>] unmap_and_move+0x8d/0x130 >> [ 3122.109957] [<ffffffff811cd47b>] migrate_pages+0xab/0x150 >> [ 3122.110788] [<ffffffff811bc440>] ? isolate_freepages+0x390/0x390 >> [ 3122.111399] [<ffffffff811bcc51>] compact_zone+0x1e1/0x2a0 >> [ 3122.111935] [<ffffffff82707e15>] ? _raw_spin_unlock_irqrestore+0x75/0xa0 >> [ 3122.112579] [<ffffffff811bcec3>] __compact_pgdat+0x1b3/0x200 >> [ 3122.113199] [<ffffffff811bcf47>] compact_node+0x37/0x40 >> [ 3122.113631] [<ffffffff81185080>] ? lru_add_drain_all+0x10/0x20 >> [ 3122.114266] [<ffffffff811bcf98>] sysfs_compact_node+0x48/0x60 >> [ 3122.114768] [<ffffffff8125c3d2>] ? sysfs_write_file+0x82/0xf0 >> [ 3122.115368] [<ffffffff81b0dc3b>] dev_attr_store+0x1b/0x20 >> [ 3122.115877] [<ffffffff8125c3ee>] sysfs_write_file+0x9e/0xf0 >> [ 3122.116423] [<ffffffff811e3258>] vfs_write+0xc8/0x190 >> [ 3122.116934] [<ffffffff811e340f>] sys_write+0x4f/0x90 >> [ 3122.117697] [<ffffffff82708cf9>] system_call_fastpath+0x16/0x1b >> [ 3122.118354] 2 locks held by trinity/17328: >> [ 3122.118694] #0: (&buffer->mutex){+.+.+.}, at: >> [<ffffffff8125c394>] sysfs_write_file+0x44/0xf0 >> [ 3122.119498] #1: (s_active#57){.+.+.+}, at: [<ffffffff8125c3d2>] >> sysfs_write_file+0x82/0xf0 > > You reported what I suppose is the same bug a week ago ("mm: hung task > (handle_pte_fault)"): the kernel is waiting for a page to come > unlocked, thinking that there is I/O outstanding against it. > > And my ugh still applies: "There are quite a lot of things which could > cause this, alas. VM, readahead, scheduler, core wait/wakeup code, IO > system, interrupt system (if it happens outside KVM, I guess). So.... > ugh. Hopefully someone will hit this in a situation where it can be > narrowed down or bisected." Oh, I didn't think that this one was related to the one I've previously reported. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href