pkg/cover: Unable to get code coverage when trying to test a .ko file

[happy2discover]

Describe the bug
Unable to get code coverage when trying to test an external .ko file. I also sent a mail to [email protected].

To Reproduce
Environment:

• Kernel: Linux 6.1.x (built with CONFIG_KASAN, CONFIG_KCOV and so on enabled)
• Syzkaller: master
• Module: A self-compiled driver (.ko).

Goals:

• Use Syzkaller to test .ko (not built into vmlinux).
• Collect code coverage data for this module.

Issues:

• How to ensure Syzkaller triggers the module's code paths?
• Are there additional configs required for coverage of dynamic modules?

Could you share a Syzkaller configuration example targeting a specific .ko, and any kernel build settings needed? Thank you for your guidance!

Expected behavior
Able to get code coverage of an external .ko file

Additional context
No.

[tomcruiseqi]

Few months ago, with Syzkaller's help, I tested some close source driver. I think your problem can be solved by following steps:

1. Merge your driver code to the mainline tree (on test environment), make sure they can be seen by kernel build system.
2. Write syzlang description codes for your driver.
3. Rebuilt Syzkaller and solve the prolems if they appear.
4. In syz-manager's configuration, enable syscalls you care.
5. Run the syz-manager and see the results.