** Changed in: linux (Ubuntu)
Status: In Progress => Fix Released
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https://bugs.launchpad.net/bugs/2022318
Title:
[SRU] IO gets stuck on 5.19 kernel
Status in linux package in Ubuntu:
Fix Released
Status in linux source package in Kinetic:
Won't Fix
Bug description:
[ Impact ]
When running fio on a NVME on an AWS test instance with 5.19 kernel,
IOs get stuck and fio never ends
fio command:
sudo fio --name=read_iops_test --filename=/dev/nvme1n1 --filesize=50G
--time_based --ramp_time=2s --runtime=1m --ioengine=libaio --direct=1
--verify=0 --randrepeat=0 --bs=16K --iodepth=256 --rw=randread
read_iops_test: (g=0): rw=randread, bs=(R) 16.0KiB-16.0KiB, (W)
16.0KiB-16.0KiB, (T) 16.0KiB-16.0KiB, ioengine=libaio, iodepth=256
fio-3.28
Starting 1 process
Jobs: 1 (f=0): [/(1)][-.-%][eta 01m:02s]
IOs completely get stuck, after a while kernel log shows:
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.230970] INFO: task fio:2545
blocked for more than 120 seconds.
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.232878] Not tainted
5.19.0-43-generic #44~22.04.1-Ubuntu
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.234738] "echo 0 >
/proc/sys/kernel/hung_task_timeout_secs" disables this message.
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237053] task:fio
state:D stack: 0 pid: 2545 ppid: 2495 flags:0x00000002
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237057] Call Trace:
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237058] <TASK>
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237061]
__schedule+0x257/0x5d0
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237066] schedule+0x68/0x110
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237068] io_schedule+0x46/0x80
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237069]
blk_mq_get_tag+0x117/0x300
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237072] ?
destroy_sched_domains_rcu+0x40/0x40
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237076]
__blk_mq_alloc_requests+0xc4/0x1e0
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237079]
blk_mq_get_new_requests+0xf6/0x1a0
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237080]
blk_mq_submit_bio+0x1eb/0x440
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237082]
__submit_bio+0x109/0x1a0
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237085]
submit_bio_noacct_nocheck+0xc2/0x120
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237087]
submit_bio_noacct+0x209/0x590
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237088] submit_bio+0x40/0xf0
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237090]
__blkdev_direct_IO_async+0x146/0x1f0
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237092]
blkdev_direct_IO.part.0+0x40/0xa0
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237093]
blkdev_read_iter+0x9f/0x1a0
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237094] aio_read+0xec/0x1d0
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237097] ?
__io_submit_one.constprop.0+0x113/0x200
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237099]
__io_submit_one.constprop.0+0x113/0x200
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237100] ?
__io_submit_one.constprop.0+0x113/0x200
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237101]
io_submit_one+0xe8/0x3d0
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237103]
__x64_sys_io_submit+0x84/0x190
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237104] ?
do_syscall_64+0x69/0x90
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237106] ?
do_syscall_64+0x69/0x90
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237107]
do_syscall_64+0x59/0x90
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237108] ?
syscall_exit_to_user_mode+0x2a/0x50
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237110] ?
do_syscall_64+0x69/0x90
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237111]
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237113] RIP:
0033:0x7f44f351ea3d
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237116] RSP:
002b:00007fff1dcfe558 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237117] RAX: ffffffffffffffda
RBX: 00007f44f2272b68 RCX: 00007f44f351ea3d
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237118] RDX: 000056315d9ad828
RSI: 0000000000000001 RDI: 00007f44f224f000
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237119] RBP: 00007f44f224f000
R08: 00007f44e9430000 R09: 00000000000002d8
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237120] R10: 0000000000000000
R11: 0000000000000246 R12: 0000000000000001
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237120] R13: 0000000000000000
R14: 000056315d9ad828 R15: 000056315d9e1830
Jun 1 03:57:52 ip-172-31-39-141 kernel: [ 370.237122] </TASK>
This issue can not be reproduced on 5.15 and 6.2 kernels
From call trace, it got stuck more than 120 seconds waiting on previous IOs
to complete for freeing some tags, so new IO requests are able to obtain tags
But in fact, not all previous IOs got stuck, at least some of previous IOs
should have completed, but the waiters were not waken up
This issue is fixed by the upstream commit below which has been merged in
kernel 6.1
commit 4acb83417cadfdcbe64215f9d0ddcf3132af808e
Author: Keith Busch <[email protected]>
Date: Fri Sep 9 11:40:22 2022 -0700
sbitmap: fix batched wait_cnt accounting
Batched completions can clear multiple bits, but we're only decrementing
the wait_cnt by one each time. This can cause waiters to never be woken,
stalling IO. Use the batched count instead.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215679
Signed-off-by: Keith Busch <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>
This commit can not be cherry picked cleanly, so we also need to SRU
all its dependencies and one further fix below:
30514bd2dd4e sbitmap: fix lockup while swapping
4acb83417cad sbitmap: fix batched wait_cnt accounting
c35227d4e8cb sbitmap: Use atomic_long_try_cmpxchg in __sbitmap_queue_get_batch
48c033314f37 sbitmap: Avoid leaving waitqueue in invalid state in
__sbq_wake_up()
ddbfc34fcf5d sbitmap: remove unnecessary code in __sbitmap_queue_get_batch
040b83fcecfb sbitmap: fix possible io hung due to lost wakeup
[ Test Plan ]
This can be simply reproduced by launching an instance on AWS EC2
And run the fio command on a nvme device for few hours to make sure IOs don’t
get stuck
I’ve built a test kernel with above commits on 5.19.0-44 generic kernel here:
https://launchpad.net/~gerald-yang-tw/+archive/ubuntu/361041-generic
With this test kernel, fio has been running for few hours without any
issue
[ Where problems could occur ]
The sbitmap is mainly used in blk-mq in block layer, scsi drivers and
fungible ethernet driver
If there is any issue happens in sbitmap, the symptom should be IO hung, or
packets get stuck in fungible driver
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