"Kernel Release isn't found"

"Kernel Release isn't found"

[Fieck, Brennan]

Hey, it's me again.


I'm having trouble using `stap -r /path/to/my/build/tree`. When I run that command (pointing it to a 4.9.70 kernel that I downloaded from kernel.org under `~/src/kernel/linux-4.9.70`) stap is printing:

"ERROR: kernel release isn't found in "/home/bwilli415/src/kernel/src/linux-4.9.70"


I used the makefile to generate a `.config` file (with `make olddefconfig`) and copied that to `config-4.9.70-x86_64` in case it's looking for that, but it didn't help. Other than that, the build tree is pristine; exactly as archived on kernel.org.

What am I missing? Is systemtap not meant to operate on raw kernel trees (e.g. only on some modified centOS/RHEL kernel source tree)?


Thanks

Brennan Fieck

Re: "Kernel Release isn't found"

[Serhei Makarov]

> I used the makefile to generate a `.config` file (with `make 
> olddefconfig`) and copied that to `config-4.9.70-x86_64` in case it's 
> looking for that, but it didn't help. Other than that, the build tree is 
> pristine; exactly as archived on kernel.org.
>
> What am I missing? Is systemtap not meant to operate on raw kernel trees 
> (e.g. only on some modified centOS/RHEL kernel source tree)?

It should work just fine on an upstream kernel, and you should not need to rename the `.config` file. However, you do need to compile your kernel (i.e. you need a *build* tree, not just a source tree) to generate the index files (such as Module.symvers) and debug information that SystemTap uses.

e.g. if I do
$ make olddefconfig
$ stap -r /path/to/my/kernel -p4 -e 'probe syscall.read { println("Hello.") exit() }'

I get the same error as you.

but if I do
$ make # compiles entire kernel
$ stap -r /path/to/my/kernel -p4 -e 'probe syscall.read { println("Hello.") exit() }'

Then SystemTap produces a kernel module.

All the best,
      Serhei