On Thu, 18 Nov 2010, Ondřej Kunc wrote: > Hi, > > I've recently tested ext4 in user mode linux VM. I compiled linux 2.6.36(from > debian source package). I configured kernel this way ... only disabled modules > (to work with default debootstraped debian). Then I created this script: > > #!/bin/bash > DD="dd if=/dev/zero bs=1k" > for i in `seq 1 1000`; do > A=$(($RANDOM%50000)) > $DD count=$A of=frag_$A > for i in `seq 1 100`; do > A=$(($RANDOM%50000)) > rm -f frag_$A > done > done > > > This script I'had run on mounted ext4 partition (/dev/ubda -> /mnt/test). It's > purpose is creating fragmented filesystem to test e4defrag. But after some > time it hungs the whole virtual system. All processes which want to write to > /mnt/test are still in D state. I issued sysrq t via uml_mconsole and in that > output I found traces below. > > Ondra I did not look at the traces closely, but did you tried another filesystem ? My experience with UML is that it is always broken so the problem might as well be somewhere else. -Lukas > > > > flush-98:16 D 0000000041a0d8b3 0 811 2 0x00000000 > 67c57d80 60276e90 69857980 6002a1ed 69857990 60013597 67c578c0 69856000 > 69856000 67c578c0 698579f0 601d3181 69857a10 601d74a0 698579f0 69856000 > ffffffff00000a57 62e09800 00000000 69ab1480 69856000 69857a58 69857aa0 > 6012274e > Call Trace: > 69857958: [<6002a1ed>] dequeue_task+0x39/0x48 > 69857968: [<60013597>] _switch_to+0x5e/0xae > 69857998: [<601d3181>] schedule+0x274/0x2ae > 698579f8: [<6012274e>] start_this_handle+0x2f4/0x395 > 69857a50: [<60042f42>] autoremove_wake_function+0x0/0x34 > 69857aa8: [<6012297c>] jbd2__journal_start+0xb9/0xf7 > 69857af8: [<601229c8>] jbd2_journal_start+0xe/0x10 > 69857b08: [<6010abe5>] ext4_journal_start_sb+0xe0/0x125 > 69857b28: [<600fa802>] ext4_meta_trans_blocks+0x5b/0xaf > 69857b68: [<60100a43>] ext4_da_writepages+0x249/0x479 > 69857c58: [<6005b042>] do_writepages+0x1c/0x25 > 69857c68: [<600908bc>] writeback_single_inode+0x93/0x1d4 > 69857c98: [<60090c4e>] writeback_sb_inodes+0xa1/0xfe > 69857cf8: [<60091364>] writeback_inodes_wb+0xc5/0xe4 > 69857d00: [<60042f76>] wake_bit_function+0x0/0x2e > 69857d48: [<600914f2>] wb_writeback+0x16f/0x1de > 69857da8: [<601d3189>] schedule+0x27c/0x2ae > 69857df8: [<60091674>] wb_do_writeback+0x113/0x130 > 69857e08: [<601d3400>] schedule_timeout+0x13e/0x15c > 69857e78: [<6009171a>] bdi_writeback_thread+0x89/0x13f > 69857eb0: [<60091691>] bdi_writeback_thread+0x0/0x13f > 69857ed0: [<60091691>] bdi_writeback_thread+0x0/0x13f > 69857ee8: [<60042c99>] kthread+0x91/0x99 > 69857f48: [<60021329>] run_kernel_thread+0x41/0x4a > 69857f58: [<60042c08>] kthread+0x0/0x99 > 69857f98: [<60021310>] run_kernel_thread+0x28/0x4a > 69857fc8: [<6001350f>] new_thread_handler+0x71/0x9b > > jbd2/ubdb-8 D 0000000041a0d8b3 0 4542 2 0x00000000 > 6838d640 60276e90 68275ca0 6002a1ed 68275cb0 60013597 6838d180 68274000 > 68274000 6838d180 68275d10 601d3181 68fd7470 601d74a0 68275d10 68274000 > 00000000 62e09800 69ab1480 1000077f1 68274000 69ab1518 68275e50 > 60122d7b > Call Trace: > 68275c78: [<6002a1ed>] dequeue_task+0x39/0x48 > 68275c88: [<60013597>] _switch_to+0x5e/0xae > 68275cb8: [<601d3181>] schedule+0x274/0x2ae > 68275d18: [<60122d7b>] jbd2_journal_commit_transaction+0x16c/0xe59 > 68275d98: [<600245e3>] switch_threads+0x2d/0x3d > 68275de0: [<60042f42>] autoremove_wake_function+0x0/0x34 > 68275df8: [<600222bb>] set_signals+0x1c/0x2e > 68275e18: [<60043094>] finish_wait+0x64/0x6f > 68275e58: [<60126168>] kjournald2+0xb8/0x1bb > 68275e90: [<60042f42>] autoremove_wake_function+0x0/0x34 > 68275eb0: [<601260b0>] kjournald2+0x0/0x1bb > 68275ed0: [<601260b0>] kjournald2+0x0/0x1bb > 68275ee8: [<60042c99>] kthread+0x91/0x99 > 68275f48: [<60021329>] run_kernel_thread+0x41/0x4a > 68275f58: [<60042c08>] kthread+0x0/0x99 > 68275f98: [<60021310>] run_kernel_thread+0x28/0x4a > 68275fc8: [<6001350f>] new_thread_handler+0x71/0x9b > > dd D 0000000041a0d8b3 0 4952 4593 0x00000000 > 6838c8c0 67c57d80 67c578f8 60284440 69b6d7a8 60013597 6838c400 69b6c000 > 69b6c000 6838c400 69b6d808 601d3181 69b6d7c8 6002a34f 69b6d808 69b6c000 > 00001000 6838c400 696c0838 00000001 ffffffffffffffff 00000000 69b6d868 > 601d43a2 > Call Trace: > 69b6d780: [<60013597>] _switch_to+0x5e/0xae > 69b6d7b0: [<601d3181>] schedule+0x274/0x2ae > 69b6d7c0: [<6002a34f>] wake_up_process+0x10/0x12 > 69b6d810: [<601d43a2>] rwsem_down_failed_common+0xb8/0xd8 > 69b6d838: [<600222bb>] set_signals+0x1c/0x2e > 69b6d870: [<601d43e9>] rwsem_down_read_failed+0x12/0x14 > 69b6d880: [<60027b98>] call_rwsem_down_read_failed+0x14/0x24 > 69b6d8c8: [<601d3b97>] down_read+0x11/0x13 > 69b6d8d8: [<600fe1cc>] ext4_map_blocks+0x3e/0x18e > 69b6d938: [<600ffe02>] ext4_da_get_block_prep+0x83/0x2bd > 69b6d958: [<60095705>] alloc_buffer_head+0x18/0x6c > 69b6d968: [<60095d31>] alloc_page_buffers+0x75/0xd1 > 69b6d9d8: [<60097105>] block_prepare_write+0x177/0x380 > 69b6d9e8: [<6005588b>] add_to_page_cache_locked+0xbf/0xe7 > 69b6da00: [<600ffd7f>] ext4_da_get_block_prep+0x0/0x2bd > 69b6da98: [<600973f3>] __block_write_begin+0x12/0x14 > 69b6daa8: [<600ffa62>] ext4_da_write_begin+0x123/0x1b4 > 69b6db28: [<60054ca0>] generic_file_buffered_write+0x124/0x27e > 69b6dbc8: [<6008889e>] file_update_time+0x3b/0xfe > 69b6dc18: [<60056634>] __generic_file_aio_write+0x380/0x3bf > 69b6dcd8: [<600566cb>] generic_file_aio_write+0x58/0xa2 > 69b6dd18: [<600f7f07>] ext4_file_write+0x92/0xa3 > 69b6dd48: [<60077a27>] do_sync_write+0xd1/0x10e > 69b6ddb8: [<60015daf>] buffer_op+0xab/0xc7 > 69b6de68: [<600783fb>] vfs_write+0xb5/0x169 > 69b6dea8: [<60078568>] sys_write+0x45/0x6c > 69b6dee8: [<60015ab8>] handle_syscall+0x58/0x70 > 69b6df08: [<60024ecb>] userspace+0x2dd/0x38a > 69b6dfc8: [<60013497>] fork_handler+0x62/0x69 > > bash D 0000000041a0d8b3 0 5324 5271 0x00000002 > 67e2c540 60276e90 67dcfbd0 6002a1ed 67dcfbe0 60013597 67e2c080 67dce000 > 67dce000 67e2c080 67dcfc40 601d3181 62a31000 601d74a0 67dcfc40 67dce000 > 67dcfc10 62e09800 00000000 69ab1480 67dce000 67dcfca8 67dcfcf0 6012274e > Call Trace: > 67dcfba8: [<6002a1ed>] dequeue_task+0x39/0x48 > 67dcfbb8: [<60013597>] _switch_to+0x5e/0xae > 67dcfbe8: [<601d3181>] schedule+0x274/0x2ae > 67dcfc48: [<6012274e>] start_this_handle+0x2f4/0x395 > 67dcfca0: [<60042f42>] autoremove_wake_function+0x0/0x34 > 67dcfcf8: [<6012297c>] jbd2__journal_start+0xb9/0xf7 > 67dcfd48: [<601229c8>] jbd2_journal_start+0xe/0x10 > 67dcfd58: [<6010abe5>] ext4_journal_start_sb+0xe0/0x125 > 67dcfd60: [<6008424f>] filldir+0x0/0x11a > 67dcfdb8: [<600fb08a>] ext4_dirty_inode+0x1b/0x48 > 67dcfdd8: [<60091027>] __mark_inode_dirty+0x29/0x199 > 67dcfdf8: [<60088a63>] touch_atime+0x102/0x125 > 67dcfe38: [<6008424f>] filldir+0x0/0x11a > 67dcfe48: [<600844fd>] vfs_readdir+0x7a/0xa1 > 67dcfe98: [<6008469d>] sys_getdents+0x90/0x124 > 67dcfee8: [<60015ab8>] handle_syscall+0x58/0x70 > 67dcff08: [<60024ecb>] userspace+0x2dd/0x38a > 67dcffc8: [<60013497>] fork_handler+0x62/0x69 > >
