Re: INFO: task systemd-udevd:794 blocked for more than 600 seconds observed after mdadm -G operation

[Shaohua Li <shli@kernel.org>]

On Fri, Aug 05, 2016 at 03:05:40PM +0800, yizhan wrote:
> 
> 
> On 08/05/2016 02:39 PM, Guoqing Jiang wrote:
> >
> >
> >On 08/04/2016 12:01 PM, Yi Zhang wrote:
> >
> >>[ 1201.734199] INFO: task systemd-udevd:794 blocked for more than 600
> >>seconds.
> >>[ 1201.734204]       Not tainted 4.7.0 #5
> >>[ 1201.734204] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
> >>disables this message.
> >>[ 1201.734206] systemd-udevd   D ffff8800310a77b0     0 794      1
> >>0x00000000
> >>[ 1201.734209]  ffff8800310a77b0 0000000000000001 ffff880031de0000
> >>ffff8807cd3c5688
> >>[ 1201.734211]  ffff8800310a8000 0000000000000000 0000000000000002
> >>ffff8807c3e4c100
> >>[ 1201.734213]  0000000000000000 ffff8800310a77c8 ffffffff816e4935
> >>ffff8807cd3c5400
> >>[ 1201.734214] Call Trace:
> >>[ 1201.734220]  [<ffffffff816e4935>] schedule+0x35/0x80
> >>[ 1201.734226]  [<ffffffffa09a0ba9>] raid5_make_request+0x8b9/0xce0
> >>[raid456]
> >>[ 1201.734229]  [<ffffffff810d0240>] ? prepare_to_wait_event+0xf0/0xf0
> >>[ 1201.734233]  [<ffffffff8156758e>] md_make_request+0xee/0x230
> >>[ 1201.734236]  [<ffffffff81320803>] generic_make_request+0x103/0x1d0
> >>[ 1201.734237]  [<ffffffff81320947>] submit_bio+0x77/0x150
> >>[ 1201.734240]  [<ffffffff813183bb>] ? bio_alloc_bioset+0x1ab/0x2d0
> >>[ 1201.734242]  [<ffffffff81254ecd>] ? alloc_page_buffers+0x5d/0xb0
> >>[ 1201.734244]  [<ffffffff81256a1f>] submit_bh_wbc+0x12f/0x160
> >>[ 1201.734246]  [<ffffffff81256d58>] block_read_full_page+0x208/0x380
> >>[ 1201.734248]  [<ffffffff81259000>] ? I_BDEV+0x20/0x20
> >>[ 1201.734250]  [<ffffffff812597e8>] blkdev_readpage+0x18/0x20
> >>[ 1201.734253]  [<ffffffff81197718>] do_read_cache_page+0x138/0x300
> >>[ 1201.734255]  [<ffffffff812597d0>] ? blkdev_writepages+0x40/0x40
> >>[ 1201.734257]  [<ffffffff811978f9>] read_cache_page+0x19/0x20
> >>[ 1201.734259]  [<ffffffff81333b50>] read_dev_sector+0x80/0xb0
> >>[ 1201.734261]  [<ffffffff81337f14>] read_lba+0x104/0x1c0
> >>[ 1201.734263]  [<ffffffff8133852a>] find_valid_gpt+0xfa/0x710
> >>[ 1201.734266]  [<ffffffff811d7d00>] ?
> >>vmap_page_range_noflush+0x190/0x380
> >>[ 1201.734267]  [<ffffffff81338b40>] ? find_valid_gpt+0x710/0x710
> >>[ 1201.734269]  [<ffffffff81338bc9>] efi_partition+0x89/0x440
> >>[ 1201.734271]  [<ffffffff81359209>] ? snprintf+0x49/0x70
> >>[ 1201.734273]  [<ffffffff81338b40>] ? find_valid_gpt+0x710/0x710
> >>[ 1201.734275]  [<ffffffff81335b31>] check_partition+0x101/0x1f0
> >>[ 1201.734277]  [<ffffffff81334462>] rescan_partitions+0xc2/0x2c0
> >>[ 1201.734279]  [<ffffffff8132f294>] __blkdev_reread_part+0x64/0x70
> >>[ 1201.734281]  [<ffffffff8132f2c3>] blkdev_reread_part+0x23/0x40
> >>[ 1201.734282]  [<ffffffff8132fd3a>] blkdev_ioctl+0x46a/0x8f0
> >>[ 1201.734284]  [<ffffffff81259aa1>] block_ioctl+0x41/0x50
> >>[ 1201.734286]  [<ffffffff812323b6>] do_vfs_ioctl+0xa6/0x5c0
> >>[ 1201.734288]  [<ffffffff81232949>] SyS_ioctl+0x79/0x90
> >>[ 1201.734290]  [<ffffffff81274d67>] ? SyS_flock+0x117/0x1a0
> >>[ 1201.734292]  [<ffffffff816e86b2>] entry_SYSCALL_64_fastpath+0x1a/0xa4
> >>[ 1201.734305] INFO: task md0_reshape:4089 blocked for more than 600
> >>seconds.
> >>[ 1201.734306]       Not tainted 4.7.0 #5
> >>[ 1201.734307] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
> >>disables this message.
> >>[ 1201.734308] md0_reshape     D ffff88080db77ac0     0 4089      2
> >>0x00000080
> >>[ 1201.734310]  ffff88080db77ac0 0000000000000000 ffff8807d6724380
> >>ffff8807cd3c5670
> >>[ 1201.734311]  ffff88080db78000 ffff88080db77b20 ffff8807cd3c5670
> >>0000000000000c20
> >>[ 1201.734313]  ffff8807cd3c5418 ffff88080db77ad8 ffffffff816e4935
> >>ffff8807cd3c5400
> >>[ 1201.734314] Call Trace:
> >>[ 1201.734316]  [<ffffffff816e4935>] schedule+0x35/0x80
> >>[ 1201.734319]  [<ffffffffa099fe8b>] raid5_get_active_stripe+0x20b/0x670
> >>[raid456]
> >>[ 1201.734321]  [<ffffffff810d0240>] ? prepare_to_wait_event+0xf0/0xf0
> >>[ 1201.734323]  [<ffffffffa09a4733>] reshape_request+0x4d3/0x8a0
> >>[raid456]
> >>[ 1201.734326]  [<ffffffffa09a4e21>] raid5_sync_request+0x321/0x3a0
> >>[raid456]
> >>[ 1201.734327]  [<ffffffff810cfc54>] ? __wake_up+0x44/0x50
> >>[ 1201.734329]  [<ffffffff8156ce97>] md_do_sync+0x9e7/0xf60
> >>[ 1201.734332]  [<ffffffff810c200d>] ? update_curr+0xed/0x180
> >>[ 1201.734333]  [<ffffffff810c025e>] ? account_entity_dequeue+0xae/0xd0
> >>[ 1201.734336]  [<ffffffff81098d43>] ? kernel_sigaction+0x43/0xe0
> >>[ 1201.734339]  [<ffffffff81566dc6>] md_thread+0x136/0x150
> >>[ 1201.734341]  [<ffffffff81566c90>] ? find_pers+0x70/0x70
> >>[ 1201.734343]  [<ffffffff810ab678>] kthread+0xd8/0xf0
> >>[ 1201.734344]  [<ffffffff816e88bf>] ret_from_fork+0x1f/0x40
> >>[ 1201.734346]  [<ffffffff810ab5a0>] ? kthread_park+0x60/0x60
> >>
> >>
> >>Reproduce steps:
> >>
> >>#mdadm -CR /dev/md0 -l5 -n4 /dev/sd[b-e]1 --write-journal /dev/sdf1
> >>#mdadm --wait /dev/md0
> >>#mdadm /dev/md0 -f /dev/sdf1
> >>#mdadm /dev/md0 -r /dev/sdf1
> >>#mdadm /dev/md0 -a /dev/sdf1
> >>#mdadm -D /dev/md0
> >>/dev/md0:
> >>         Version : 1.2
> >>   Creation Time : Thu Aug  4 20:37:41 2016
> >>      Raid Level : raid5
> >>      Array Size : 31432704 (29.98 GiB 32.19 GB)
> >>   Used Dev Size : 10477568 (9.99 GiB 10.73 GB)
> >>    Raid Devices : 4
> >>   Total Devices : 5
> >>     Persistence : Superblock is persistent
> >>
> >>     Update Time : Thu Aug  4 20:40:16 2016
> >>           State : clean
> >>  Active Devices : 4
> >>Working Devices : 5
> >>  Failed Devices : 0
> >>   Spare Devices : 1
> >>
> >>          Layout : left-symmetric
> >>      Chunk Size : 512K
> >>
> >>            Name : dhcp-12-125.nay.redhat.com:0  (local to host
> >>dhcp-12-125.nay.redhat.com)
> >>            UUID : 09607542:a8dccc81:f5d2f80c:c586923f
> >>          Events : 22
> >>
> >>     Number   Major   Minor   RaidDevice State
> >>        0       8       17        0      active sync   /dev/sdb1
> >>        1       8       33        1      active sync   /dev/sdc1
> >>        2       8       49        2      active sync   /dev/sdd1
> >>        5       8       65        3      active sync   /dev/sde1
> >>
> >>        4       8       81        -      spare   /dev/sdf1
> >>
> >>#mdadm -G -n5 /dev/md0
> >
> >Also with 4.7+, I can't find the same issue, but md0_reshape is in 'D'
> >state from my side
> >(actually I can't find reshape is in-progress by 'cat /proc/mdstat').
> >
> Hi guoqing
> Thanks for you detailed log.
> The trace cannot be print soon, I think you need wait for more time, the
> time from below is more than 15m.
> Aug  4 20:39:37 dhcp-12-125 kernel: md/raid:md0: Disk failure on sdf1,
> disabling device.#012md/raid:md0: Operation continuing on 4 devices.
> Aug  4 20:39:56 dhcp-12-125 kernel: md: unbind<sdf1>
> Aug  4 20:39:56 dhcp-12-125 kernel: md: export_rdev(sdf1)
> Aug  4 20:40:16 dhcp-12-125 kernel: md: bind<sdf1>
> Aug  4 20:40:47 dhcp-12-125 kernel: md: reshape of RAID array md0
> Aug  4 20:40:47 dhcp-12-125 kernel: md: minimum _guaranteed_  speed: 1000
> KB/sec/disk.
> Aug  4 20:40:47 dhcp-12-125 kernel: md: using maximum available idle IO
> bandwidth (but not more than 200000 KB/sec) for reshape.
> Aug  4 20:40:47 dhcp-12-125 kernel: md: using 128k window, over a total of
> 10477568k
> Aug  4 20:55:56 dhcp-12-125 kernel: INFO: task systemd-udevd:794 blocked for
> more than 600 seconds.

Adding Song who knows a lot in this side.

If an array is created with journal and journal disk fails, we will make the
array read-only. So we should disable reshape too. Likely we have a bug here.

Thanks,
Shaohua