On Tue, Nov 06, 2007 at 10:04:51PM +0100, Milan Broz wrote: > Petar Bogdanovic wrote: > > I experience some strange problems with my loopback-on-ext3-setup. > > After creating a plain `zeroed' dummy-file and doing a /dev/loop/0 on > > it, every dd or mke2fs hangs while doing certain write()s. Here are the > > steps just in order to show, how simple the setup is: > ... > > > P.S: $ uname -a > > Linux pintail 2.6.23-ARCH #1 SMP PREEMPT Sat Oct 27 09:04:14 UTC > > 2007 i686 Intel(R) Pentium(R) M processor 1.70GHz GenuineIntel > > GNU/Linux > > Hi Petar, > > I saw similar bug report for dm-crypt over loop but reproducible even > on stand-alone loop devices - see > http://bugzilla.kernel.org/show_bug.cgi?id=8020 > > The problem was caused by loop io stalling in balance_dirty_pages. > > Per BDI dirty limit patchset (included in 2.6.24-rc) fixed it. > > Anyway, you should attach output of process states when system stops > responding (output of "echo t >/proc/sysrq-trigger" ) here to allow > some analysis.
Thanks Milane! :) Here are the process states: dd `hanging' on a 1GB zeroed loopback: ======================= dd D eb52fcc0 0 10152 9657 eb52fcd4 00200086 00000002 eb52fcc0 eb52fcb8 00000000 c047aee0 c047de80 eb52fcc4 ed192550 c180ce80 00000000 00152450 00000000 0000000f 00000000 00000000 00000000 eb52fce4 0015246d 000055bd eb52fd0c c035fb0a 00000001 Call Trace: [<c035fb0a>] schedule_timeout+0x4a/0xc0 [<c0135240>] process_timeout+0x0/0x10 [<c035f4be>] io_schedule_timeout+0x1e/0x30 [<c0166976>] congestion_wait+0x56/0x80 [<c0140200>] autoremove_wake_function+0x0/0x40 [<c0161701>] balance_dirty_pages_ratelimited_nr+0x141/0x220 [<c015cc1a>] generic_file_buffered_write+0x37a/0x6b0 [<c01489f8>] tick_program_event+0x38/0x60 [<c015d204>] __generic_file_aio_write_nolock+0x2b4/0x530 [<c013165b>] irq_exit+0x5b/0x90 [<c015d5a7>] generic_file_aio_write_nolock+0x47/0xb0 [<c0168b07>] unmap_vmas+0x537/0x610 [<c017df15>] do_sync_write+0xd5/0x120 [<c0140200>] autoremove_wake_function+0x0/0x40 [<c017de40>] do_sync_write+0x0/0x120 [<c017e7cf>] vfs_write+0xbf/0x140 [<c017ee61>] sys_write+0x41/0x70 [<c0104482>] sysenter_past_esp+0x6b/0xa1 ======================= and mke2fs `hanging' on a 30GB sparse file loopback: ======================= mke2fs D e6bcdcc0 0 10767 9657 e6bcdcd4 00200086 00000002 e6bcdcc0 e6bcdcb8 00000000 c047aee0 c047de80 e6bcdcc4 dfe1f540 c180ce80 00000000 0017c1f9 00000000 0000000f 00000000 00000000 00000000 e6bcdce4 0017c259 000055c4 e6bcdd0c c035fb0a 00000001 Call Trace: [<c035fb0a>] schedule_timeout+0x4a/0xc0 [<c0135240>] process_timeout+0x0/0x10 [<c035f4be>] io_schedule_timeout+0x1e/0x30 [<c0166976>] congestion_wait+0x56/0x80 [<c0140200>] autoremove_wake_function+0x0/0x40 [<c0161701>] balance_dirty_pages_ratelimited_nr+0x141/0x220 [<c015cc1a>] generic_file_buffered_write+0x37a/0x6b0 [<c015d204>] __generic_file_aio_write_nolock+0x2b4/0x530 [<c0124233>] __check_preempt_curr_fair+0x53/0xa0 [<c0128dd7>] check_preempt_curr_fair+0x57/0x90 [<c015d5a7>] generic_file_aio_write_nolock+0x47/0xb0 [<c01030b1>] __switch_to+0xa1/0x150 [<c017df15>] do_sync_write+0xd5/0x120 [<c0140200>] autoremove_wake_function+0x0/0x40 [<c017de40>] do_sync_write+0x0/0x120 [<c017e7cf>] vfs_write+0xbf/0x140 [<c017db1c>] vfs_llseek+0x3c/0x50 [<c017ee61>] sys_write+0x41/0x70 [<c0104482>] sysenter_past_esp+0x6b/0xa1 [<c0360000>] __mutex_lock_interruptible_slowpath+0x120/0x340 ======================= If you need more output, just tell me. Thanks & with kind regards, Petar - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
