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python: read Py_Version when filename lacks a version #1124

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Merged
christos68k merged 7 commits into from
Apr 15, 2026
Merged

python: read Py_Version when filename lacks a version #1124

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baa8bd7
python: fall back to Py_Version when filename lacks a version
dkratunov Jan 8, 2026
ca3ce00
review feedback
dkratunov Feb 17, 2026
40932ab
Merge upstream/main into pyversion-lookup
dkratunov Feb 18, 2026
5f0d1d6
python: avoid int-to-uint16 narrowing in pythonVer
dkratunov Feb 18, 2026
1f4ef25
Merge branch 'main' into pyversion-lookup
dkratunov Mar 3, 2026
06a7dad
python: address codeql atoi
dkratunov Mar 20, 2026
f07186a
skip versionHex explicit check
dkratunov Apr 13, 2026
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41 changes: 37 additions & 4 deletions interpreter/python/python.go
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@ import (
"errors"
"fmt"
"io"
"path"
"reflect"
"regexp"
"slices"
Expand Down Expand Up @@ -48,6 +49,23 @@ func pythonVer(major, minor uint16) uint16 {
return major*0x100 + minor
}

func readPyVersionHex(ef *pfelf.File) (major uint8, minor uint8, err error) {
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@korniltsev-grafanista korniltsev-grafanista Mar 20, 2026

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can we add a coredump test hitting this logic?

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@dkratunov dkratunov Apr 13, 2026

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It's not super easy for arbitrary contributors to add core dumps afaict. Do I not need s3 put access first?

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@dalehamel dalehamel Apr 14, 2026

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It's not super easy for arbitrary contributors to add core dumps afaict. Do I not need s3 put access first?

create a google drive link (or similar shareable blob store) and share it with one of the maintainers giving them read access, @florianl has been very helpful with uploading coredumps for the ruby tests.

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@florianl florianl Apr 14, 2026

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A full coredump test might be a bit much to test this function. Therefore it is fine for me to continue and merge it without. A more simpler way to test readPyVersionHex() could be to have a base64 encoded data string, like helloworldBin in testsupport, and add a regular unit test.

// Py_Version is referenced in CPython internals for versioned Python binaries.
// https://github.com/python/cpython/blob/v3.11.0/Doc/c-api/apiabiversion.rst
addr, err := ef.LookupSymbolAddress("Py_Version")
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if err != nil {
return 0, 0, err
}
rm := ef.GetRemoteMemory()
versionHex := rm.Uint32(libpf.Address(addr))
major = uint8((versionHex >> 24) & 0xff)
minor = uint8((versionHex >> 16) & 0xff)
if major == 0 {
return 0, 0, fmt.Errorf("invalid Py_Version 0x%x", versionHex)
}
return major, minor, nil
}

//nolint:lll
type pythonData struct {
version uint16
Expand Down Expand Up @@ -721,19 +739,36 @@ func decodeStub(ef *pfelf.File, memoryBase libpf.SymbolValue,

func Loader(ebpf interpreter.EbpfHandler, info *interpreter.LoaderInfo) (interpreter.Data, error) {
mainDSO := false
major := uint16(0)
minor := uint16(0)
matches := libpythonRegex.FindStringSubmatch(info.FileName())
if matches == nil {
mainDSO = true
matches = pythonRegex.FindStringSubmatch(info.FileName())
if matches == nil {
}
if matches == nil {
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@korniltsev-grafanista korniltsev-grafanista Mar 20, 2026

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nit: can we move readPyVersionHex invocation under this matches==nil case block and avoid major == 0 check ?

if !strings.HasPrefix(path.Base(info.FileName()), "python") {
return nil, nil
}
} else {
majorValue, _ := strconv.ParseUint(matches[1], 10, 16)
minorValue, _ := strconv.ParseUint(matches[2], 10, 16)
major = uint16(majorValue)
minor = uint16(minorValue)
}

ef, err := info.GetELF()
if err != nil {
return nil, err
}
if major == 0 {
majorFromSym, minorFromSym, versionErr := readPyVersionHex(ef)
if versionErr != nil {
return nil, nil
}
major = uint16(majorFromSym)
minor = uint16(minorFromSym)
}

if mainDSO {
var needed []string
Expand All @@ -749,9 +784,7 @@ func Loader(ebpf interpreter.EbpfHandler, info *interpreter.LoaderInfo) (interpr
}

var pyruntimeAddr, autoTLSKey libpf.SymbolValue
major, _ := strconv.ParseUint(matches[1], 10, 16)
minor, _ := strconv.ParseUint(matches[2], 10, 16)
version := pythonVer(uint16(major), uint16(minor))
version := pythonVer(major, minor)

minVer := pythonVer(3, 6)
maxVer := pythonVer(3, 14)
Expand Down
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