Trying to view Merge Request gives Server Error 500

Summary

I had closed the issue previously because it started working again...but it came back. Can't access Merge Request; GET request returns 500 error. I should add that this was working last week. I hadn't changed anything and this stopped working seemingly over the weekend for some reason.

Steps to reproduce

On my installation, it happens every time I click on a specific merge request.

What is the current bug behavior?

When clicking on a Merge Request, I am taken to a 500 error status page.

Relevant logs and/or screenshots

Looking at the production logs, the issue is the following:

Started GET "/group/project-name/merge_requests/1" for 192.168.1.1 at 2019-08-19 15:33:40 -0400
Processing by Projects::MergeRequestsController#show as HTML
Parameters: {"namespace_id"=>"namespace", "project_id"=>"project", "id"=>"1"}

Completed 500 Internal Server Error in 60ms (ActiveRecord: 4.7ms)

Rugged::OSError (failed stat - '/var/opt/gitlab/git-data/repositories/repo/project.git/objects/bf/190ea342b4f601edfboeu58dd707e998db14' is locked: Permission denied):

Output of checks

Results of GitLab environment info

Expand for output related to the GitLab environment info check

System information
System:	Ubuntu 16.04
Current User:	git
Using RVM:	no
Ruby Version:	2.6.3p62
Gem Version:	2.7.9
Bundler Version:1.17.3
Rake Version:	12.3.2
Redis Version:	3.2.12
Git Version:	2.21.0
Sidekiq Version:5.2.7
Go Version:	unknown
GitLab information
Version:	12.1.6
Revision:	4016bcac51d
Directory:	/opt/gitlab/embedded/service/gitlab-rails
DB Adapter:	PostgreSQL
DB Version:	10.7
URL:	http://gitlab.company.com
HTTP Clone URL:	http://gitlab.company.com/some-group/some-project.git
SSH Clone URL:	git@gitlab.company.com:some-group/some-project.git
Using LDAP:	no
Using Omniauth:	yes
Omniauth Providers:
GitLab Shell
Version:	9.3.0
Repository storage paths:
- default: /var/opt/gitlab/git-data/repositories
GitLab Shell path:	/opt/gitlab/embedded/service/gitlab-shell
Git:	/opt/gitlab/embedded/bin/git

Results of GitLab application Check

Expand for output related to the GitLab application check

Checking GitLab subtasks ...
Checking GitLab Shell ...
GitLab Shell: ... GitLab Shell version >= 9.3.0 ? ... OK (9.3.0)
Running /opt/gitlab/embedded/service/gitlab-shell/bin/check
Check GitLab API access: OK
Redis available via internal API: OK
Access to /var/opt/gitlab/.ssh/authorized_keys: OK
gitlab-shell self-check successful
Checking GitLab Shell ... Finished
Checking Gitaly ...
Gitaly: ... default ... OK
Checking Gitaly ... Finished
Checking Sidekiq ...
Sidekiq: ... Running? ... yes
Number of Sidekiq processes ... 1
Checking Sidekiq ... Finished
Checking Incoming Email ...
Incoming Email: ... Reply by email is disabled in config/gitlab.yml
Checking Incoming Email ... Finished
Checking LDAP ...
LDAP: ... LDAP is disabled in config/gitlab.yml
Checking LDAP ... Finished
Checking GitLab App ...
Git configured correctly? ... yes
Database config exists? ... yes
All migrations up? ... yes
Database contains orphaned GroupMembers? ... no
GitLab config exists? ... yes
GitLab config up to date? ... yes
Log directory writable? ... yes
Tmp directory writable? ... yes
Uploads directory exists? ... yes
Uploads directory has correct permissions? ... yes
Uploads directory tmp has correct permissions? ... yes
Init script exists? ... skipped (omnibus-gitlab has no init script)
Init script up-to-date? ... skipped (omnibus-gitlab has no init script)
Projects have namespace: ...
3/1 ... yes
3/2 ... yes
3/3 ... yes
3/4 ... yes
3/5 ... yes
3/6 ... yes
3/7 ... yes
3/8 ... yes
3/9 ... yes
3/10 ... yes
3/11 ... yes
3/12 ... yes
3/15 ... yes
3/16 ... yes
3/17 ... yes
3/18 ... yes
3/19 ... yes
3/20 ... yes
3/21 ... yes
3/22 ... yes
9/23 ... yes
3/24 ... yes
3/25 ... yes
3/26 ... yes
3/27 ... yes
3/28 ... yes
3/29 ... yes
3/30 ... yes
3/31 ... yes
3/33 ... yes
3/34 ... yes
11/35 ... yes
3/36 ... yes
3/38 ... yes
3/39 ... yes
3/40 ... yes
11/41 ... yes
11/42 ... yes
11/43 ... yes
11/44 ... yes
11/45 ... yes
11/46 ... yes
3/47 ... yes
3/49 ... yes
3/50 ... yes
11/51 ... yes
3/52 ... yes
3/53 ... yes
11/54 ... yes
11/55 ... yes
3/56 ... yes
11/57 ... yes
11/58 ... yes
11/59 ... yes
11/60 ... yes
11/61 ... yes
3/62 ... yes
3/63 ... yes
3/64 ... yes
3/66 ... yes
3/67 ... yes
3/68 ... yes
3/69 ... yes
3/70 ... yes
3/71 ... yes
3/72 ... yes
3/73 ... yes
3/74 ... yes
3/75 ... yes
3/76 ... yes
3/77 ... yes
3/78 ... yes
3/79 ... yes
3/80 ... yes
11/81 ... yes
3/82 ... yes
20/83 ... yes
3/84 ... yes
11/85 ... yes
11/86 ... yes
11/87 ... yes
3/88 ... yes
11/89 ... yes
3/90 ... yes
15/91 ... yes
15/92 ... yes
15/93 ... yes
15/94 ... yes
3/95 ... yes
20/96 ... yes
15/97 ... yes
15/98 ... yes
3/99 ... yes
15/100 ... yes
3/101 ... yes
2/102 ... yes
3/103 ... yes
3/104 ... yes
11/105 ... yes
3/106 ... yes
3/107 ... yes
20/108 ... yes
11/109 ... yes
3/110 ... yes
15/111 ... yes
16/112 ... yes
3/114 ... yes
3/115 ... yes
18/116 ... yes
3/117 ... yes
3/118 ... yes
3/119 ... yes
11/120 ... yes
3/121 ... yes
3/122 ... yes
3/124 ... yes
3/125 ... yes
3/126 ... yes
3/127 ... yes
3/128 ... yes
3/129 ... yes
11/130 ... yes
13/131 ... yes
18/132 ... yes
3/133 ... yes
18/134 ... yes
Redis version >= 2.8.0? ... yes
Ruby version >= 2.5.3 ? ... yes (2.6.3)
Git version >= 2.21.0 ? ... yes (2.21.0)
Git user has default SSH configuration? ... yes
Active users: ... 7
Checking GitLab App ... Finished
Checking GitLab subtasks ... Finished

Possible fixes

Seems like it occurs in: Projects::MergeRequestsController#show as HTML And the error seems to be: Rugged::OSError (failed stat - '/var/opt/gitlab/git-data/repositories/repo/project.git/objects/bf/sha1' is locked: Permission denied

gitlab-ce2278648 gitlab-ce9789536