Please provide as much information as possible when reporting a bug or filing an issue on the Windows Subsystem for Linux.

Important: Reporting BSODs and Security issues

Do not open GitHub issues for Windows crashes (BSODs) or security issues.. Instead, send Windows crashes or other security-related issues to secure@microsoft.com. See the 10) Reporting a Windows crash (BSOD) section below for detailed instructions.

Reporting issues in Windows Console or WSL text rendering/user experience

Note that WSL distro's launch in the Windows Console (unless you have taken steps to launch a 3rd party console/terminal). Therefore, please file UI/UX related issues in the Windows Console issue tracker.

Reporting issues in WSL

A well written bug report will follow the following template:

1) Issue Title

A title succinctly describing the issue.

Example:

Traceroute not working.

2) Windows version / build number

Your Windows build number. This can be gathered from the CMD prompt using the cmd.exe --version command.

C:\ cmd.exe --version
Microsoft Windows [Version 10.0.21354.1]

Note: The Windows Insider builds contain many updates and fixes. If you are running on the Creators Update (10.0.15063) please check to see if your issue has been resolved in a later build. If you are running on a Version below (10.0.14393), please try to update your Version.

Example:

Microsoft Windows [Version 10.0.21354.1]

3) Steps required to reproduce

Should include all packages and environmental variables as well as other required configuration.

Example: On linux

$ sudo apt-get install traceroute && traceroute www.microsoft.com

Example: On Windows

`$ cmd.exe` `CD C:\Windows\System32\` `tracert.exe`

4) Copy of the terminal output

Example:

$ traceroute www.microsoft.com
traceroute to www.microsoft.com (23.75.239.28), 30 hops max, 60 byte packets
setsockopt IP_MTU_DISCOVER: Invalid argument

5) Expected Behavior

What was the expected result of the command? Include examples / documentation if possible.

6) Strace of the failing command

Run the failing command under strace. Normal command structure is:

$ strace -ff <command>

Note: strace can produce lengthy output. If the generated trace is more than about 20 lines please paste this into a Gist or another paste service and link in the bug.

Example:

$ strace traceroute www.microsoft.com
execve("/usr/bin/traceroute", ["traceroute", "www.microsoft.com"], [/* 22 vars */]) = 0
brk(0)                                  = 0x7fffdd3bc000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f1f4e820000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
...
...
...

7) Additional information

Some bugs require additional information such as scripts to reproduce. Please add to this section.

If there are files required, email the files to InsiderSupport@microsoft.com with:

• Subject: Forward to WSL Team - RE: github issue <issue #>
• Body: "Please forward to WSL Team" and include your attachment.

Common files are:

• Memory dumps found under C:\Windows\MEMORY.DMP
• Additional strace logs if the error occurs within a fork. The following command generates an output file for every fork created:

$ strace -ff -o <outputfile> <command>

wsl --mount

If the issue is about wsl --mount, please include the output of running wmic diskdrive get Availability,Capabilities,CapabilityDescriptions,DeviceID,InterfaceType,MediaLoaded,MediaType,Model,Name,Partitions in an elevated command prompt.

Example:

C:\WINDOWS\system32>wmic diskdrive get Availability,Capabilities,CapabilityDescriptions,DeviceID,InterfaceType,MediaLoaded,MediaType,Model,Name,Partitions
Availability  Capabilities  CapabilityDescriptions                                       DeviceID            InterfaceType  MediaLoaded  MediaType              Model                       Name                Partitions
              {3, 4}        {"Random Access", "Supports Writing"}                        \\.\PHYSICALDRIVE0  SCSI           TRUE         Fixed hard disk media  SAMSUNG MZVLB512HAJQ-000H2  \\.\PHYSICALDRIVE0  3
              {3, 4}        {"Random Access", "Supports Writing"}                        \\.\PHYSICALDRIVE1  SCSI           TRUE         Fixed hard disk media  SAMSUNG MZVLB1T0HALR-000H2  \\.\PHYSICALDRIVE1  1
              {3, 4, 10}    {"Random Access", "Supports Writing", "SMART Notification"}  \\.\PHYSICALDRIVE2  SCSI           TRUE         Fixed hard disk media  ST2000DM001-1ER164          \\.\PHYSICALDRIVE2  1

Collect WSL logs for networking issues

Install tcpdump in your WSL distribution using the following commands. Note: This will not work if WSL has Internet connectivity issues.

# sudo apt-get update
# sudo apt-get -y install tcpdump

Install WPR

To collect WSL networking logs, do the following steps in an administrative powershell prompt:

Invoke-WebRequest -UseBasicParsing "https://raw.githubusercontent.com/microsoft/WSL/master/diagnostics/collect-networking-logs.ps1" -OutFile collect-networking-logs.ps1
Set-ExecutionPolicy Bypass -Scope Process -Force
.\collect-networking-logs.ps1

The script will output when log collection starts. Reproduce the problem, then press any key to stop the log collection. The script will output the path of the log file once done.

8) Collect WSL logs (recommended method)

If you choose to email these logs instead of attaching to the bug, please send them to wsl-gh-logs@microsoft.com with the number of the github issue in the subject, and in the message a link to your comment in the github issue.

To collect WSL logs, download and execute collect-wsl-logs.ps1 in an administrative powershell prompt:

Invoke-WebRequest -UseBasicParsing "https://raw.githubusercontent.com/microsoft/WSL/master/diagnostics/collect-wsl-logs.ps1" -OutFile collect-wsl-logs.ps1
Set-ExecutionPolicy Bypass -Scope Process -Force
.\collect-wsl-logs.ps1

The script will output the path of the log file once done.

9) Collect WSL logs with Feedback hub

To collect WSL logs follow these steps:

Open Feedback Hub and enter the title and description of your issue

• Open Feedback hub and create a new issue by pressing Windows Key + F on your keyboard.
• Enter in the details of your issue:
  • In Summarize your feedback copy and paste in the title of your Github Issue
  • In Explain in more detail copy and paste a link to your Github Issue

Choose the WSL category

• Select that your issue is a Problem
• Choose the Developer Platform category and the Windows Subsystem for Linux subcategory

Recreate your problem in the 'Additional Details' section

• Select 'Other' under 'Which of the following best describes your problem'
• Click 'Recreate My Problem' under 'Attachments
• Ensure that Include Data About: is checked to 'Windows Subsystem for Linux'
• 'Click Start Recording' to start collecting logs
• Recreate your problem
• Click 'Stop Recording'

Check your attachments and submit

• Verify your recording is attached and whether you would like to send the screenshot that is automatically attached
• Hit Submit
• Get a link to your feedback item by clicking on 'Share my Feedback' and post that link to the Github thread so we can easily get to your feedback!

10) Reporting a Windows crash (BSOD)

To collect a kernel crash dump, first run the following command in an elevated command prompt:

reg.exe add HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CrashControl /v AlwaysKeepMemoryDump  /t REG_DWORD /d 1 /f

Then reproduce the issue, and let the machine crash and reboot.

After reboot, the kernel dump will be in %SystemRoot%\MEMORY.DMP (unless this path has been overriden in the advanced system settings).

Please send this dump to: secure@microsoft.com . Make sure that the email body contains:

• The Github issue number, if any
• That this dump is destinated to the WSL team

11) Reporting a WSL process crash

The easiest way to report a WSL process crash is by collecting a user-mode crash dump.

To collect dumps of all running WSL processe, please open a PowerShell prompt with admin privileges, navigate to a folder where you'd like to put your log files and run these commands:

Invoke-WebRequest -UseBasicParsing "https://raw.githubusercontent.com/microsoft/WSL/master/diagnostics/collect-wsl-logs.ps1" -OutFile collect-wsl-logs.ps1
Set-ExecutionPolicy Bypass -Scope Process -Force
.\collect-wsl-logs.ps1 -Dump

The script will output the path to the log file when it is done.

Enable automatic crash dump collection

If your crash is sporadic or hard to reproduce, please enable automatic crash dumps to catch logs for this behavior:

md C:\crashes
reg.exe add "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Windows Error Reporting\LocalDumps" /f
reg.exe add "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Windows Error Reporting\LocalDumps" /v DumpFolder /t REG_EXPAND_SZ /d C:\crashes /f
reg.exe add "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Windows Error Reporting\LocalDumps" /v DumpType /t REG_DWORD /d 2 /f

Crash dumps will then automatically be written to C:\crashes.

Once you're done, crash dump collection can be disabled by running the following command in an elevated command prompt:

reg.exe delete "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Windows Error Reporting\LocalDumps" /f

12) Collect wslservice time travel debugging traces

To collect time travel debugging traces:

1. Install Windbg preview

2. Open windbg preview as administrator by running windbgx in an elevated command prompt

3. Navigate to file -> Attach to process

4. Check Record with Time Travel Debugging (at the bottom right)

5. Check Show processes from all users (at the bottom)

6. Select wslservice.exe. Note, if wslservice.exe is not running, you make it start it with: wsl.exe -l

7. Click Configure and Record (write down the folder you chose for the traces)

8. Reproduce the issue

9. Go back to windbg and click Stop and Debug

10. Once the trace is done collecting, click Stop Debugging and close Windbg

11. Go to the folder where the trace was colleced, and locate the .run file. It should look like: wslservice*.run

12. Share that file on the issue