Hi,
I am testing 3 SSDs (1TB Crucial M550 with DRZAT, and I tested they do
return zeros after discard) with RAID5 and discard. I create the array
with a 64k chunk size, and it starts to sync. During it's initial
reconstruction, I do a mkfs.ext4, which starts to do the "Discarding
device blocks". After a short period (I believe when the mkfs reaches
the point where the reconstruction is at, all IO to the disks freezes,
and mkfs does not advance. iostat shows 2 of the 3 drives at 100%
utilization with no data read or written. After 2 minutes, I get the
hung task dump. Most CPUs are idle, and here are a few which are not,
which look like a deadlock to me:
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154399] INFO:
rcu_sched detected stalls on CPUs/tasks: { 4 5} (detected by 3,
t=285032 jiffies, g=1160, c=1159, q=0)
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154902] NMI
backtrace for cpu 4
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154904] CPU: 4 PID:
2146 Comm: md3_raid5 Tainted: G W IOX 3.13.0-43-generic
#72~precise1
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154905] Hardware
name: Supermicro SYS-2028TP-HC1R/X10DRT-P, BIOS 1.0a 08/28/2014
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154906] task:
ffff88202594c800 ti: ffff8810245a0000 task.ti: ffff8810245a0000
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154907] RIP:
0010:[<ffffffff817644c1>] [<ffffffff817644c1>]
_raw_spin_lock_irqsave+0x41/0x60
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154910] RSP:
0018:ffff8810245a1cc8 EFLAGS: 00000006
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154911] RAX:
0000000000002ec5 RBX: ffff882028a6ec00 RCX: 0000000000007b78
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154912] RDX:
0000000000000202 RSI: 0000000000007b78 RDI: ffff882028a6ec10
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154913] RBP:
ffff8810245a1cc8 R08: 0000000000007b76 R09: ffff882023629170
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154914] R10:
0000000000000000 R11: ffff882028a6ec00 R12: ffff882028a6ee68
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154915] R13:
0000000000000003 R14: 0000000000000002 R15: ffff882028a6ec10
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154916] FS:
0000000000000000(0000) GS:ffff88103fc80000(0000)
knlGS:0000000000000000
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154917] CS: 0010
DS: 0000 ES: 0000 CR0: 0000000080050033
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154918] CR2:
00007f208c2d0000 CR3: 0000000001c0d000 CR4: 00000000001407e0
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154919] Stack:
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154920]
ffff8810245a1d18 ffffffffa0149890 0000000000000002 ffff882028a6ee88
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154923]
ffff882028a6ee68 ffff882028a6ec00 0000000000000008 ffff882028a6ee68
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154926]
0000000000000000 ffff882028a6ee50 ffff8810245a1d98 ffffffffa015212f
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154929] Call Trace:
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154933]
[<ffffffffa0149890>] release_inactive_stripe_list+0x50/0x160 [raid456]
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154937]
[<ffffffffa015212f>] handle_active_stripes.isra.38+0x7f/0x190
[raid456]
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154940]
[<ffffffffa0152758>] raid5d+0x198/0x2f0 [raid456]
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154942]
[<ffffffff815d30a7>] md_thread+0x117/0x150
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154945]
[<ffffffff810affe0>] ? __wake_up_sync+0x20/0x20
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154947]
[<ffffffff815d2f90>] ? md_rdev_init+0x110/0x110
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154949]
[<ffffffff8108fb59>] kthread+0xc9/0xe0
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154952]
[<ffffffff8108fa90>] ? flush_kthread_worker+0xb0/0xb0
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154954]
[<ffffffff8176d5bc>] ret_from_fork+0x7c/0xb0
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154956]
[<ffffffff8108fa90>] ? flush_kthread_worker+0xb0/0xb0
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.154957] Code: 1f 44
00 00 b8 00 00 02 00 f0 0f c1 07 89 c1 c1 e9 10 66 39 c1 75 05 48 89
d0 5d c3 83 e1 fe 0f b7 f1 b8 00 80 00 00 44 0f b7 07 <66> 44 39 c1 74
e6 f3 90 83 e8 01 75 ef 0f 1f 80 00 00 00 00 eb
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155001] NMI
backtrace for cpu 5
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155003] CPU: 5 PID:
2147 Comm: md3_resync Tainted: G W IOX 3.13.0-43-generic
#72~precise1
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155004] Hardware
name: Supermicro SYS-2028TP-HC1R/X10DRT-P, BIOS 1.0a 08/28/2014
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155005] task:
ffff88202594b000 ti: ffff8810274a0000 task.ti: ffff8810274a0000
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155006] RIP:
0010:[<ffffffffa01483b7>] [<ffffffffa01483b7>]
__find_stripe+0x57/0xa0 [raid456]
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155010] RSP:
0018:ffff8810274a1b68 EFLAGS: 00000006
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155011] RAX:
ffff882027092da0 RBX: 0000000000a30c10 RCX: 0000000000000001
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155012] RDX:
0000000000000c10 RSI: 0000000000a30c10 RDI: ffff882028a6ec00
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155013] RBP:
ffff8810274a1b88 R08: 0000000000000000 R09: 0000000000000000
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155014] R10:
0000000000000000 R11: 0000000000000001 R12: 0000000000000000
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155015] R13:
ffff882028a6ec00 R14: 0000000000000000 R15: ffff882028a6eda8
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155016] FS:
0000000000000000(0000) GS:ffff88103fca0000(0000)
knlGS:0000000000000000
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155017] CS: 0010
DS: 0000 ES: 0000 CR0: 0000000080050033
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155018] CR2:
00000000006e1dc8 CR3: 0000000001c0d000 CR4: 00000000001407e0
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155019] Stack:
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155020]
ffff8810274a1ba8 ffff882028a6ec00 000000007b767b00 ffff882028a6ec10
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155023]
ffff8810274a1c28 ffffffffa0150555 ffff882023773b50 ffff882028a6eda8
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155026]
0000000200000001 ffff882028a6ec08 0000000000000000 0000000000a30c10
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155029] Call Trace:
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155033]
[<ffffffffa0150555>] get_active_stripe+0x115/0x3e0 [raid456]
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155036]
[<ffffffffa014aea8>] ? release_stripe+0x68/0x100 [raid456]
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155040]
[<ffffffffa0154f3b>] sync_request+0x11b/0x2a0 [raid456]
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155042]
[<ffffffff815d5ccf>] md_do_sync+0x84f/0xdb0
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155046]
[<ffffffff810affe0>] ? __wake_up_sync+0x20/0x20
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155048]
[<ffffffff815d30a7>] md_thread+0x117/0x150
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155050]
[<ffffffff815d2f90>] ? md_rdev_init+0x110/0x110
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155052]
[<ffffffff8108fb59>] kthread+0xc9/0xe0
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155054]
[<ffffffff8108fa90>] ? flush_kthread_worker+0xb0/0xb0
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155057]
[<ffffffff8176d5bc>] ret_from_fork+0x7c/0xb0
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155059]
[<ffffffff8108fa90>] ? flush_kthread_worker+0xb0/0xb0
Dec 18 00:57:41 unassigned-hostname kernel: [ 1606.155060] Code: e2 f8
0f 00 00 48 8b 04 02 48 85 c0 75 25 f6 05 29 25 01 00 04 75 3e 31 c0
48 83 c4 08 5b 41 5c 41 5d 5d c3 66 44 39 60 30 74 ee <48> 8b 00 48 85
c0 74 db 48 39 58 38 75 f2 eb e9 48 89 f2 48 c7
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670082] INFO: task
mkfs.ext4:2235 blocked for more than 120 seconds.
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670109]
Tainted: G W IOX 3.13.0-43-generic #72~precise1
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670130] "echo 0 >
/proc/sys/kernel/hung_task_timeout_secs" disables this message.
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670155] mkfs.ext4
D ffff881024fe39e0 0 2235 2080 0x00000000
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670158]
ffff882026eafa68 0000000000000082 ffff88103fc73480 ffff882026eaffd8
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670162]
0000000000013480 0000000000013480 ffff8820293e8000 ffff88202208b000
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670165]
ffff882026eafa78 ffff882028a6ec00 ffff882028a6ed98 ffff882028a6ec0c
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670169] Call Trace:
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670175]
[<ffffffff81760ae9>] schedule+0x29/0x70
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670181]
[<ffffffffa01506e3>] get_active_stripe+0x2a3/0x3e0 [raid456]
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670185]
[<ffffffff8134c152>] ? blk_check_plugged+0x72/0xb0
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670189]
[<ffffffff810affe0>] ? __wake_up_sync+0x20/0x20
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670193]
[<ffffffffa0155e44>] make_discard_request+0x108/0x12c4 [raid456]
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670196]
[<ffffffff810affe0>] ? __wake_up_sync+0x20/0x20
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670201]
[<ffffffffa0155c91>] make_request+0x581/0x590 [raid456]
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670204]
[<ffffffff8109cfd6>] ? ttwu_do_activate.constprop.82+0x66/0x70
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670207]
[<ffffffff8109d097>] ? ttwu_queue+0xb7/0xd0
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670210]
[<ffffffff8109f950>] ? try_to_wake_up+0x190/0x210
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670212]
[<ffffffff815d2c53>] md_make_request+0xd3/0x230
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670216]
[<ffffffff8115b085>] ? mempool_alloc_slab+0x15/0x20
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670219]
[<ffffffff8134ceb7>] generic_make_request.part.62+0x77/0xb0
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670222]
[<ffffffff8134d428>] generic_make_request+0x68/0x70
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670225]
[<ffffffff8134d4a8>] submit_bio+0x78/0x160
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670228]
[<ffffffff81202f80>] ? bio_alloc_bioset+0xa0/0x1d0
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670232]
[<ffffffff813578c0>] blkdev_issue_discard+0x1f0/0x2a0
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670235]
[<ffffffff8135c1f4>] blkdev_ioctl+0x354/0x810
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670238]
[<ffffffff8101361d>] ? __switch_to+0x16d/0x4d0
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670241]
[<ffffffff81204370>] block_ioctl+0x40/0x50
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670244]
[<ffffffff811dd5c5>] do_vfs_ioctl+0x75/0x2c0
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670247]
[<ffffffff817606be>] ? __schedule+0x38e/0x700
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670249]
[<ffffffff811dd8a1>] SyS_ioctl+0x91/0xb0
Dec 18 00:58:57 unassigned-hostname kernel: [ 1682.670252]
[<ffffffff8176d66d>] system_call_fastpath+0x1a/0x1f
If I do the mkfs.ext4 after the initial reconstruction is done, is
gets all the way through. I don't want to put this system into
production, since this could mean this condition could show up in the
future if the array needs to reconstruct again at a future point while
in service.
This is a test system in a lab, so I'd be happy to try some tests.
Terry
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