Bug 42778

Summary:	Partition checking code hangs on empty virtio disk
Product:	File System	Reporter:	Richard W.M. Jones (rjones)
Component:	Other	Assignee:	fs_other
Status:	RESOLVED INVALID
Severity:	normal	CC:	amon
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:		Subsystem:
Regression:	No	Bisected commit-id:

Description Richard W.M. Jones 2012-02-15 19:49:19 UTC

Ubuntu bug report is here:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/931371

Attaching a completely blank disk image to a virtual machine causes the following stack trace when loading the virtio block driver:

[ 1.106728] loop: module loaded
[ 1.125680] vda: unknown partition table
[ 1.789721] Switching to clocksource tsc
[ 8.373409] Clocksource tsc unstable (delta = 87849991 ns)
[ 8.374642] Switching to clocksource jiffies
[ 241.037694] INFO: task swapper/0:1 blocked for more than 120 seconds.
[ 241.037966] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 241.038424] swapper/0 D ffffffff81806240 0 1 0 0x00000000
[ 241.039028] ffff88001ed7d870 0000000000000046 0000000000000000 000000004dbb1e54
[ 241.039460] ffff88001ed7dfd8 ffff88001ed7dfd8 ffff88001ed7dfd8 0000000000013780
[ 241.039839] ffffffff81c0d020 ffff88001ed80000 ffff88001ed7d850 ffff88001f014040
[ 241.040220] Call Trace:
[ 241.041349] [<ffffffff811157a0>] ? __lock_page+0x70/0x70
[ 241.041712] [<ffffffff8165574f>] schedule+0x3f/0x60
[ 241.041798] [<ffffffff816557ff>] io_schedule+0x8f/0xd0
[ 241.041943] [<ffffffff811157ae>] sleep_on_page+0xe/0x20
[ 241.045386] [<ffffffff81655eca>] __wait_on_bit_lock+0x5a/0xc0
[ 241.045467] [<ffffffff81115797>] __lock_page+0x67/0x70
[ 241.049105] [<ffffffff81089e60>] ? autoremove_wake_function+0x40/0x40
[ 241.049416] [<ffffffff81116a20>] do_read_cache_page+0x160/0x180
[ 241.049656] [<ffffffff811ad630>] ? blkdev_write_begin+0x30/0x30
[ 241.049783] [<ffffffff81116a89>] read_cache_page_async+0x19/0x20
[ 241.049931] [<ffffffff81116a9e>] read_cache_page+0xe/0x20
[ 241.053417] [<ffffffff811e14bd>] read_dev_sector+0x2d/0x90
[ 241.053629] [<ffffffff811e2604>] adfspart_check_ICS+0x74/0x2d0
[ 241.053834] [<ffffffff81311f64>] ? snprintf+0x34/0x40
[ 241.053987] [<ffffffff811e2590>] ? rescan_partitions+0x300/0x300
[ 241.054210] [<ffffffff811e1c38>] check_partition+0xf8/0x200
[ 241.057501] [<ffffffff811e236a>] rescan_partitions+0xda/0x300
[ 241.057746] [<ffffffff811ae68c>] __blkdev_get+0x2bc/0x420
[ 241.057888] [<ffffffff810899f7>] ? bit_waitqueue+0x17/0xc0
[ 241.058000] [<ffffffff811ae84e>] blkdev_get+0x5e/0x1e0
[ 241.058080] [<ffffffff812f6b62>] register_disk+0x162/0x180
[ 241.058177] [<ffffffff812f6c24>] add_disk+0xa4/0x1b0
[ 241.061902] [<ffffffff8162925a>] virtblk_probe+0x43d/0x4e2
[ 241.064195] [<ffffffff814083f0>] ? virtblk_config_changed+0x30/0x30
[ 241.065436] [<ffffffff813a3020>] ? vp_find_vqs+0xc0/0xc0
[ 241.065529] [<ffffffff813a15e3>] virtio_dev_probe+0xe3/0x140
[ 241.065617] [<ffffffff813f08d8>] really_probe+0x68/0x190
[ 241.065701] [<ffffffff813f0b65>] driver_probe_device+0x45/0x70
[ 241.065789] [<ffffffff813f0c3b>] __driver_attach+0xab/0xb0
[ 241.065873] [<ffffffff813f0b90>] ? driver_probe_device+0x70/0x70
[ 241.065962] [<ffffffff813f0b90>] ? driver_probe_device+0x70/0x70
[ 241.066051] [<ffffffff813ef9cc>] bus_for_each_dev+0x5c/0x90
[ 241.066137] [<ffffffff813f069e>] driver_attach+0x1e/0x20
[ 241.069422] [<ffffffff813f02f0>] bus_add_driver+0x1a0/0x270
[ 241.073426] [<ffffffff81d2fcb8>] ? loop_init+0x12f/0x12f
[ 241.073641] [<ffffffff813f11a6>] driver_register+0x76/0x140
[ 241.073801] [<ffffffff81d2fcb8>] ? loop_init+0x12f/0x12f
[ 241.073951] [<ffffffff813a1840>] register_virtio_driver+0x20/0x30
[ 241.077413] [<ffffffff81d2fd0a>] init+0x52/0x7c
[ 241.077611] [<ffffffff81002040>] do_one_initcall+0x40/0x180
[ 241.077760] [<ffffffff81cf9ce9>] kernel_init+0xcf/0x14e
[ 241.077913] [<ffffffff81661d74>] kernel_thread_helper+0x4/0x10
[ 241.078061] [<ffffffff81cf9c1a>] ? start_kernel+0x3c7/0x3c7
[ 241.081352] [<ffffffff81661d70>] ? gs_change+0x13/0x13

This happens with 3.2.0 and a more recent 3.3 kernel.

Comment 1 Richard W.M. Jones 2012-04-14 15:43:10 UTC

Still happening with 3.4.0-rc2+.

It happens when CONFIG_ACORN_PARTITION_ICS=y (not "ADFS"
as previously stated).  I've updated the summary to
reflect this.

I can reproduce it easily using my own kernel compiled
from Linus's git tree.

I can only reproduce it in an Ubuntu VM (not on Fedora
baremetal) although that is probably just a timing issue.

Comment 2 Richard W.M. Jones 2012-04-14 16:20:00 UTC

More oddness.  I disabled all CONFIG_ACORN_PARTITION settings.

The bug still happens!  But in another partition function.

[  240.632690] INFO: task swapper/0:1 blocked for more than 120 seconds.
[  240.632891] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[  240.633222] swapper/0       D ffffffff8180ca80     0     1      0 0x00000000
[  240.633623]  ffff88001e911750 0000000000000046 0000000000000000 000000004e14c044
[  240.633930]  ffff88001e908000 ffff88001e911fd8 ffff88001e911fd8 ffff88001e911fd8
[  240.634167]  ffffffff81c13020 ffff88001e908000 ffff88001e911730 ffff88001ec140e8
[  240.634461] Call Trace:
[  240.635197]  [<ffffffff81119840>] ? __lock_page+0x70/0x70
[  240.635428]  [<ffffffff81655979>] schedule+0x29/0x70
[  240.635602]  [<ffffffff81655a4f>] io_schedule+0x8f/0xd0
[  240.635755]  [<ffffffff8111984e>] sleep_on_page+0xe/0x20
[  240.635907]  [<ffffffff816540fa>] __wait_on_bit_lock+0x5a/0xc0
[  240.636130]  [<ffffffff81119837>] __lock_page+0x67/0x70
[  240.636283]  [<ffffffff81073840>] ? autoremove_wake_function+0x40/0x40
[  240.636472]  [<ffffffff8111aa70>] do_read_cache_page+0x160/0x180
[  240.636486]  [<ffffffff811b0170>] ? blkdev_write_begin+0x30/0x30
[  240.636486]  [<ffffffff8111aad9>] read_cache_page_async+0x19/0x20
[  240.636486]  [<ffffffff8111aaee>] read_cache_page+0xe/0x20
[  240.636486]  [<ffffffff812f832d>] read_dev_sector+0x2d/0x90
[  240.636486]  [<ffffffff812fe68c>] read_lba+0xbc/0x120
[  240.636486]  [<ffffffff812feaeb>] find_valid_gpt+0xbb/0x610
[  240.636486]  [<ffffffff81316d7e>] ? string.isra.4+0x3e/0xd0
[  240.636486]  [<ffffffff812ff040>] ? find_valid_gpt+0x610/0x610
[  240.636486]  [<ffffffff812ff0c2>] efi_partition+0x82/0x3b0
[  240.636486]  [<ffffffff813182c4>] ? snprintf+0x34/0x40
[  240.636486]  [<ffffffff812ff040>] ? find_valid_gpt+0x610/0x610
[  240.636486]  [<ffffffff812f93b8>] check_partition+0xf8/0x200
[  240.636486]  [<ffffffff812f9017>] rescan_partitions+0xb7/0x2b0
[  240.636486]  [<ffffffff811b13cb>] __blkdev_get+0x39b/0x480
[  240.636486]  [<ffffffff811937f2>] ? inode_init_always+0x102/0x1d0
[  240.636486]  [<ffffffff811b1503>] blkdev_get+0x53/0x310
[  240.636486]  [<ffffffff8119311c>] ? unlock_new_inode+0x5c/0x90
[  240.636486]  [<ffffffff811b0021>] ? bdget+0x121/0x140
[  240.636486]  [<ffffffff812f6885>] add_disk+0x3f5/0x490
[  240.636486]  [<ffffffff816343ff>] virtblk_probe+0x45f/0x503
[  240.636486]  [<ffffffff81413c20>] ? lo_release+0x90/0x90
[  240.636486]  [<ffffffff813a9af0>] ? vp_reset+0x90/0x90
[  240.640804]  [<ffffffff813a8053>] virtio_dev_probe+0xe3/0x140
[  240.641851]  [<ffffffff813fa30e>] driver_probe_device+0x7e/0x220
[  240.642170]  [<ffffffff813fa55b>] __driver_attach+0xab/0xb0
[  240.642518]  [<ffffffff813fa4b0>] ? driver_probe_device+0x220/0x220
[  240.642821]  [<ffffffff813f8746>] bus_for_each_dev+0x56/0x90
[  240.643101]  [<ffffffff813f9e2e>] driver_attach+0x1e/0x20
[  240.643372]  [<ffffffff813f99e0>] bus_add_driver+0x1a0/0x270
[  240.643665]  [<ffffffff81d28240>] ? loop_init+0x12e/0x12e
[  240.643939]  [<ffffffff81d28240>] ? loop_init+0x12e/0x12e
[  240.644282]  [<ffffffff813faab6>] driver_register+0x76/0x130
[  240.644613]  [<ffffffff81d28240>] ? loop_init+0x12e/0x12e
[  240.644887]  [<ffffffff813a82b0>] register_virtio_driver+0x20/0x30
[  240.644989]  [<ffffffff81d28294>] init+0x54/0x7e
[  240.644989]  [<ffffffff8100203f>] do_one_initcall+0x3f/0x170
[  240.644989]  [<ffffffff81cf2d53>] kernel_init+0x134/0x1b8
[  240.644989]  [<ffffffff81cf2549>] ? rdinit_setup+0x28/0x28
[  240.644989]  [<ffffffff8165fe64>] kernel_thread_helper+0x4/0x10
[  240.644989]  [<ffffffff81cf2c1f>] ? start_kernel+0x3ce/0x3ce
[  240.644989]  [<ffffffff8165fe60>] ? gs_change+0x13/0x13

Comment 3 Dale Amon 2012-04-14 18:24:03 UTC

I have seen the same condition as Richard, using the same applications, but on a raw virtual disk with multiple primary and extended partitions and a functioning MBR using the most recent Precise Pangolin release's Ubuntu kernel. So it is more general than just a blank disk. It fails on a fully functional virtual disk.

Comment 4 Richard W.M. Jones 2012-04-15 16:16:17 UTC

I now believe this is a bug in the Ubuntu qemu package.