Can not work in gevent/eventlet model

# Checklist



* [x] I have verified that the issue exists against the `master` branch of Celery.
* [ ] This has already been asked to the [discussion group](https://groups.google.com/forum/#!forum/celery-users) first.
* [x] I have read the relevant section in the
 [contribution guide](http://docs.celeryproject.org/en/latest/contributing.html#other-bugs)
 on reporting bugs.
* [x] I have checked the [issues list](https://github.com/celery/celery/issues?q=is%3Aissue+label%3A%22Issue+Type%3A+Bug+Report%22+-label%3A%22Category%3A+Documentation%22)
 for similar or identical bug reports.
* [x] I have checked the [pull requests list](https://github.com/celery/celery/pulls?q=is%3Apr+label%3A%22PR+Type%3A+Bugfix%22+-label%3A%22Category%3A+Documentation%22)
 for existing proposed fixes.
* [x] I have checked the [commit log](https://github.com/celery/celery/commits/master)
 to find out if the bug was already fixed in the master branch.
* [x] I have included all related issues and possible duplicate issues
 in this issue (If there are none, check this box anyway).

## Mandatory Debugging Information
* [x] I have included the output of ``celery -A proj report`` in the issue.
 (if you are not able to do this, then at least specify the Celery
 version affected).
* [x] I have verified that the issue exists against the `master` branch of Celery.
* [x] I have included the contents of ``pip freeze`` in the issue.
* [x] I have included all the versions of all the external dependencies required
 to reproduce this bug.

## Optional Debugging Information



* [x] I have tried reproducing the issue on more than one Python version
 and/or implementation.
* [x] I have tried reproducing the issue on more than one message broker and/or
 result backend.
* [x] I have tried reproducing the issue on more than one version of the message
 broker and/or result backend.
* [x] I have tried reproducing the issue on more than one operating system.
* [x] I have tried reproducing the issue on more than one workers pool.
* [x] I have tried reproducing the issue with autoscaling, retries,
 ETA/Countdown & rate limits disabled.
* [x] I have tried reproducing the issue after downgrading
 and/or upgrading Celery and its dependencies.

## Related Issues and Possible Duplicates


#### Related Issues
* #4758
* #6111 

#### Possible Duplicates
* None

## Environment & Settings

**Celery version**: 4.4.6

<details>
<summary><code>celery report</code> Output:</summary>


```
software -> celery:4.4.6 (cliffs) kombu:4.6.11 py:3.6.10
 billiard:3.6.3.0 librabbitmq:2.0.0
platform -> system:Linux arch:64bit
 kernel version:4.19.104-microsoft-standard imp:CPython
loader -> celery.loaders.app.AppLoader
settings -> transport:librabbitmq results:redis://:**@127.0.0.1:6379/8

broker_url: 'amqp://myuser:********@127.0.0.1:5672/myvhost'
result_backend: 'redis://:********@127.0.0.1:6379/8'
timezone: 'Asia/Shanghai'
```


</details>

# Steps to Reproduce
## Required Dependencies



* **Minimal Python Version**: 3.6
* **Minimal Celery Version**: 4.4.6
* **Minimal Kombu Version**: 4.6.11
* **Minimal Broker Version**: N/A or Unknown
* **Minimal Result Backend Version**: N/A or Unknown
* **Minimal OS and/or Kernel Version**: Ubuntu18.04 LTS (WSL2)
* **Minimal Broker Client Version**: N/A or Unknown
* **Minimal Result Backend Client Version**: N/A or Unknown

### Python Packages

<details>
<summary><code>pip freeze</code> Output:</summary>


```
amqp==2.6.0
billiard==3.6.3.0
celery==4.4.6
certifi==2020.6.20
future==0.18.2
gevent==20.6.2
greenlet==0.4.16
importlib-metadata==1.7.0
kombu==4.6.11
librabbitmq==2.0.0
pytz==2020.1
redis==3.5.3
six==1.15.0
vine==1.3.0
zipp==3.1.0
zope.event==4.4
zope.interface==5.1.0
```


</details>

### Other Dependencies

<details>

N/A

</details>

## Minimally Reproducible Test Case


<details>


```
from celery import Celery
app = Celery(
 "proj",
 broker='amqp://myuser:mypassword@127.0.0.1/myvhost',
 backend="redis://:127.0.0.1:6379/8",
)
@app.task()
def add(x, y):
 return x+y
```

Just a simple app with 'add' function to return the sum of two number. Run this app by 'celery -A proj -P=gevent -c=10 -l debug'.And than open anonther shell, call the 'add' function by 'res = add.delay(2,2)' and 'res.get()'

</details>

# Expected Behavior

'res.get()' should return '4' as result


# Actual Behavior

'res.get()' seems block forever and never return, it can be seen from the log that the task was indeed accepted'

```
[2020-07-13 23:56:20,345: DEBUG/MainProcess] | Worker: Preparing bootsteps.
[2020-07-13 23:56:20,347: DEBUG/MainProcess] | Worker: Building graph...
[2020-07-13 23:56:20,347: DEBUG/MainProcess] | Worker: New boot order: {Timer, Hub, Pool, Autoscaler, Beat, StateDB, Consumer}
[2020-07-13 23:56:20,365: DEBUG/MainProcess] | Consumer: Preparing bootsteps.
[2020-07-13 23:56:20,365: DEBUG/MainProcess] | Consumer: Building graph...
[2020-07-13 23:56:20,379: DEBUG/MainProcess] | Consumer: New boot order: {Connection, Events, Mingle, Gossip, Heart, Tasks, Control, Agent, event loop}

 -------------- celery@SURFACEBOOK-2 v4.4.6 (cliffs)
--- ***** -----
-- ******* ---- Linux-4.19.104-microsoft-standard-x86_64-with-debian-buster-sid 2020-07-13 23:56:20
- *** --- * ---
- ** ---------- [config]
- ** ---------- .> app: Heimdallr:0x7f2e0135d6d8
- ** ---------- .> transport: amqp://myuser:**@127.0.0.1/myvhost
- ** ---------- .> results: redis://:**@127.0.0.1:6379/8
- *** --- * --- .> concurrency: 10 (gevent)
-- ******* ---- .> task events: OFF (enable -E to monitor tasks in this worker)
--- ***** -----
 -------------- [queues]
 .> celery exchange=celery(direct) key=celery


[tasks]
 . celery.accumulate
 . celery.backend_cleanup
 . celery.chain
 . celery.chord
 . celery.chord_unlock
 . celery.chunks
 . celery.group
 . celery.map
 . celery.starmap
 . worker.add

[2020-07-13 23:56:20,400: DEBUG/MainProcess] | Worker: Starting Hub
[2020-07-13 23:56:20,400: DEBUG/MainProcess] ^-- substep ok
[2020-07-13 23:56:20,400: DEBUG/MainProcess] | Worker: Starting Pool
[2020-07-13 23:56:20,400: DEBUG/MainProcess] ^-- substep ok
[2020-07-13 23:56:20,400: DEBUG/MainProcess] | Worker: Starting Consumer
[2020-07-13 23:56:20,401: DEBUG/MainProcess] | Consumer: Starting Connection
[2020-07-13 23:56:20,702: INFO/MainProcess] Connected to amqp://myuser:**@127.0.0.1:5672/myvhost
[2020-07-13 23:56:20,702: DEBUG/MainProcess] ^-- substep ok
[2020-07-13 23:56:20,703: DEBUG/MainProcess] | Consumer: Starting Events
[2020-07-13 23:56:21,024: DEBUG/MainProcess] ^-- substep ok
[2020-07-13 23:56:21,025: DEBUG/MainProcess] | Consumer: Starting Mingle
[2020-07-13 23:56:21,025: INFO/MainProcess] mingle: searching for neighbors
[2020-07-13 23:56:23,152: INFO/MainProcess] mingle: sync with 1 nodes
[2020-07-13 23:56:23,153: DEBUG/MainProcess] mingle: processing reply from celery@instance-och4ruob
[2020-07-13 23:56:23,153: INFO/MainProcess] mingle: sync complete
[2020-07-13 23:56:23,153: DEBUG/MainProcess] ^-- substep ok
[2020-07-13 23:56:23,154: DEBUG/MainProcess] | Consumer: Starting Gossip
[2020-07-13 23:56:23,549: DEBUG/MainProcess] ^-- substep ok
[2020-07-13 23:56:23,549: DEBUG/MainProcess] | Consumer: Starting Heart
[2020-07-13 23:56:23,693: DEBUG/MainProcess] ^-- substep ok
[2020-07-13 23:56:23,694: DEBUG/MainProcess] | Consumer: Starting Tasks
[2020-07-13 23:56:23,993: DEBUG/MainProcess] ^-- substep ok
[2020-07-13 23:56:23,993: DEBUG/MainProcess] | Consumer: Starting Control
[2020-07-13 23:56:23,994: DEBUG/MainProcess] ^-- substep ok
[2020-07-13 23:56:23,994: DEBUG/MainProcess] | Consumer: Starting event loop
[2020-07-13 23:56:23,994: DEBUG/MainProcess] | Worker: Hub.register Pool...
[2020-07-13 23:56:24,072: INFO/MainProcess] celery@SURFACEBOOK-2 ready.
[2020-07-13 23:56:24,074: DEBUG/MainProcess] basic.qos: prefetch_count->40
[2020-07-13 23:57:14,569: INFO/MainProcess] Received task: worker.add[de4e08e4-336d-465f-ac2e-da55faea1b73]
[2020-07-13 23:57:14,569: DEBUG/MainProcess] TaskPool: Apply <function _fast_trace_task at 0x7f2e012f5268> (args:('worker.add', 'de4e08e4-336d-465f-ac2e-da55faea1b73', {'lang': 'py', 'task': 'worker.add', 'id': 'de4e08e4-336d-465f-ac2e-da55faea1b73', 'shadow': None, 'eta': None, 'expires': None, 'group': None, 'retries': 0, 'timelimit': [None, None], 'root_id': 'de4e08e4-336d-465f-ac2e-da55faea1b73', 'parent_id': None, 'argsrepr': '(2, 2)', 'kwargsrepr': '{}', 'origin': 'gen3136@SURFACEBOOK-2', 'reply_to': '419b4639-2e20-3278-a057-6c4fea63e811', 'correlation_id': 'de4e08e4-336d-465f-ac2e-da55faea1b73', 'hostname': 'celery@SURFACEBOOK-2', 'delivery_info': {'exchange': '', 'routing_key': 'celery', 'priority': 0, 'redelivered': False}, 'args': [2, 2], 'kwargs': {}}, <memory at 0x7f2e01eef048>, 'application/json', 'utf-8') kwargs:{})
[2020-07-13 23:57:50,615: INFO/MainProcess] Received task: worker.add[dcba734c-2251-4abc-a1a5-1c31289bd8f1]
[2020-07-13 23:57:50,615: DEBUG/MainProcess] TaskPool: Apply <function _fast_trace_task at 0x7f2e012f5268> (args:('worker.add', 'dcba734c-2251-4abc-a1a5-1c31289bd8f1', {'lang': 'py', 'task': 'worker.add', 'id': 'dcba734c-2251-4abc-a1a5-1c31289bd8f1', 'shadow': None, 'eta': None, 'expires': None, 'group': None, 'retries': 0, 'timelimit': [None, None], 'root_id': 'dcba734c-2251-4abc-a1a5-1c31289bd8f1', 'parent_id': None, 'argsrepr': '(2, 2)', 'kwargsrepr': '{}', 'origin': 'gen8514@SURFACEBOOK-2', 'reply_to': '3bee5d65-442f-3d41-9d9e-25c88986b473', 'correlation_id': 'dcba734c-2251-4abc-a1a5-1c31289bd8f1', 'hostname': 'celery@SURFACEBOOK-2', 'delivery_info': {'exchange': '', 'routing_key': 'celery', 'priority': 0, 'redelivered': True}, 'args': [2, 2], 'kwargs': {}}, <memory at 0x7f2e01eef108>, 'application/json', 'utf-8') kwargs:{})[2020-07-13 23:57:50,615: INFO/MainProcess] Received task: worker.add[90f858e9-b259-4968-8d59-e546cdc07515]
[2020-07-13 23:57:50,616: DEBUG/MainProcess] TaskPool: Apply <function _fast_trace_task at 0x7f2e012f5268> (args:('worker.add', '90f858e9-b259-4968-8d59-e546cdc07515', {'lang': 'py', 'task': 'worker.add', 'id': '90f858e9-b259-4968-8d59-e546cdc07515', 'shadow': None, 'eta': None, 'expires': None, 'group': None, 'retries': 0, 'timelimit': [None, None], 'root_id': '90f858e9-b259-4968-8d59-e546cdc07515', 'parent_id': None, 'argsrepr': '(2, 2)', 'kwargsrepr': '{}', 'origin': 'gen8514@SURFACEBOOK-2', 'reply_to': '3bee5d65-442f-3d41-9d9e-25c88986b473', 'correlation_id': '90f858e9-b259-4968-8d59-e546cdc07515', 'hostname': 'celery@SURFACEBOOK-2', 'delivery_info': {'exchange': '', 'routing_key': 'celery', 'priority': 0, 'redelivered': True}, 'args': [2, 2], 'kwargs': {}}, <memory at 0x7f2e01eef1c8>, 'application/json', 'utf-8') kwargs:{})[2020-07-13 23:57:51,809: INFO/MainProcess] Received task: worker.add[10eb7374-3151-4ca3-b307-2319e1b20878]
[2020-07-13 23:57:51,809: DEBUG/MainProcess] TaskPool: Apply <function _fast_trace_task at 0x7f2e012f5268> (args:('worker.add', '10eb7374-3151-4ca3-b307-2319e1b20878', {'lang': 'py', 'task': 'worker.add', 'id': '10eb7374-3151-4ca3-b307-2319e1b20878', 'shadow': None, 'eta': None, 'expires': None, 'group': None, 'retries': 0, 'timelimit': [None, None], 'root_id': '10eb7374-3151-4ca3-b307-2319e1b20878', 'parent_id': None, 'argsrepr': '(2, 2)', 'kwargsrepr': '{}', 'origin': 'gen2895@SURFACEBOOK-2', 'reply_to': '21261e1d-cfc1-3f6b-bfce-cb52049e69a0', 'correlation_id': '10eb7374-3151-4ca3-b307-2319e1b20878', 'hostname': 'celery@SURFACEBOOK-2', 'delivery_info': {'exchange': '', 'routing_key': 'celery', 'priority': 0, 'redelivered': True}, 'args': [2, 2], 'kwargs': {}}, <memory at 0x7f2e01eef288>, 'application/json', 'utf-8') kwargs:{})[2020-07-13 23:58:13,122: INFO/MainProcess] Received task: worker.add[d3d9fe2d-6cfe-4db9-8b77-dfb83c7f1041]
[2020-07-13 23:58:13,122: DEBUG/MainProcess] TaskPool: Apply <function _fast_trace_task at 0x7f2e012f5268> (args:('worker.add', 'd3d9fe2d-6cfe-4db9-8b77-dfb83c7f1041', {'lang': 'py', 'task': 'worker.add', 'id': 'd3d9fe2d-6cfe-4db9-8b77-dfb83c7f1041', 'shadow': None, 'eta': None, 'expires': None, 'group': None, 'retries': 0, 'timelimit': [None, None], 'root_id': 'd3d9fe2d-6cfe-4db9-8b77-dfb83c7f1041', 'parent_id': None, 'argsrepr': '(2, 2)', 'kwargsrepr': '{}', 'origin': 'gen3136@SURFACEBOOK-2', 'reply_to': '419b4639-2e20-3278-a057-6c4fea63e811', 'correlation_id': 'd3d9fe2d-6cfe-4db9-8b77-dfb83c7f1041', 'hostname': 'celery@SURFACEBOOK-2', 'delivery_info': {'exchange': '', 'routing_key': 'celery', 'priority': 0, 'redelivered': False}, 'args': [2, 2], 'kwargs': {}}, <memory at 0x7f2e01eef348>, 'application/json', 'utf-8') kwargs:{})
[2020-07-13 23:58:47,723: DEBUG/MainProcess] celery@instance-och4ruob joined the party
[2020-07-13 23:58:54,904: DEBUG/MainProcess] celery@instance-och4ruob left
^C
worker: Hitting Ctrl+C again will terminate all running tasks!

worker: Warm shutdown (MainProcess)
[2020-07-13 23:59:40,326: DEBUG/MainProcess] | Worker: Closing Hub...
[2020-07-13 23:59:40,326: DEBUG/MainProcess] | Worker: Closing Pool...
[2020-07-13 23:59:40,326: DEBUG/MainProcess] | Worker: Closing Consumer...
[2020-07-13 23:59:40,326: DEBUG/MainProcess] | Worker: Stopping Consumer...
[2020-07-13 23:59:40,327: DEBUG/MainProcess] | Consumer: Closing Connection...
[2020-07-13 23:59:40,327: DEBUG/MainProcess] | Consumer: Closing Events...
[2020-07-13 23:59:40,327: DEBUG/MainProcess] | Consumer: Closing Mingle...
[2020-07-13 23:59:40,327: DEBUG/MainProcess] | Consumer: Closing Gossip...
[2020-07-13 23:59:40,327: DEBUG/MainProcess] | Consumer: Closing Heart...
[2020-07-13 23:59:40,327: DEBUG/MainProcess] | Consumer: Closing Tasks...
[2020-07-13 23:59:40,327: DEBUG/MainProcess] | Consumer: Closing Control...
[2020-07-13 23:59:40,328: DEBUG/MainProcess] | Consumer: Closing event loop...
[2020-07-13 23:59:40,328: DEBUG/MainProcess] | Consumer: Stopping event loop...
[2020-07-13 23:59:40,328: DEBUG/MainProcess] | Consumer: Stopping Control...
[2020-07-13 23:59:40,328: DEBUG/MainProcess] | Consumer: Stopping Tasks...
[2020-07-13 23:59:40,347: DEBUG/MainProcess] Canceling task consumer...
[2020-07-13 23:59:40,425: DEBUG/MainProcess] | Consumer: Stopping Heart...
[2020-07-13 23:59:40,427: DEBUG/MainProcess] | Consumer: Stopping Gossip...
[2020-07-13 23:59:40,594: DEBUG/MainProcess] | Consumer: Stopping Mingle...
[2020-07-13 23:59:40,595: DEBUG/MainProcess] | Consumer: Stopping Events...
[2020-07-13 23:59:40,595: DEBUG/MainProcess] | Consumer: Stopping Connection...
[2020-07-13 23:59:40,595: DEBUG/MainProcess] | Worker: Stopping Pool...
[2020-07-13 23:59:40,906: INFO/MainProcess] pidbox: Connected to amqp://myuser:**@127.0.0.1:5672/myvhost.
[2020-07-13 23:59:49,674: DEBUG/MainProcess] pidbox received method ping() [reply_to:{'exchange': 'reply.celery.pidbox', 'routing_key': '713a54e8-d3d0-3682-926d-ea821da864fd'} ticket:c6616862-2365-48be-9dd2-38368b7cf343]
^C
worker: Cold shutdown (MainProcess)
```

When use 'celery -A worker inspect ping', it just return 'Error: No nodes replied within time constraint.Error: No nodes replied within time constraint'. If I start multiple different worker(all in gevent model), they can not find each other. **But if I start a worker in prefork model, it just works perfectly.** Another strange thing is that if press crtl+c, the worker can not warm shutdown completely, 'pidbox: Connected to amqp://myuser:**@127.0.0.1:5672/myvhost.'will appear. If use 'celery -A worker inspect ping' again, it will return a 'pong'.
I have already tried py3.6 and py3.7/redis as broker/rabbitmq as broker/gevent/eventlet/ubutnu18/ubuntu16, the results are basically the same.

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Can not work in gevent/eventlet model #6225

Checklist

Mandatory Debugging Information

Optional Debugging Information

Related Issues and Possible Duplicates

Related Issues

Possible Duplicates

Environment & Settings

Steps to Reproduce

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Uh oh!

Uh oh!

Can not work in gevent/eventlet model #6225

Description

Checklist

Mandatory Debugging Information

Optional Debugging Information

Related Issues and Possible Duplicates

Related Issues

Possible Duplicates

Environment & Settings

Steps to Reproduce

Required Dependencies

Python Packages

Other Dependencies

Minimally Reproducible Test Case

Expected Behavior

Actual Behavior

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

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