panic in process.ProcessesWithContext on freebsd

[sni]

Describe the bug
I updated from v4.25.6 to v4.25.7 and now process.ProcessesWithContext panics on FreeBSD.

To Reproduce

process.ProcessesWithContext(context.TODO())

Expected behavior
It should not panic.

Environment (please complete the following information):

• FreeBSD: freebsd-14.3 with golang 1.23.10

Additional context
i think the issue has been introduced here:

• fde2488#diff-6a294f9d28dbad7750b7c02441cb98a594b1eeacc4c78b4809eea1970e991543L475-L538

There have not been that many changes since the last 2 versions.

the panic log:

2025-08-11T12:16:14.9000734Z panic: reflect: call of reflect.Value.Field on int32 Value [recovered]
2025-08-11T12:16:14.9001407Z 	panic: reflect: call of reflect.Value.Field on int32 Value
2025-08-11T12:16:14.9001754Z 
2025-08-11T12:16:14.9001863Z goroutine 213 [running]:
2025-08-11T12:16:14.9002223Z testing.tRunner.func1.2({0xb8a560, 0x86c11a360})
2025-08-11T12:16:14.9002795Z 	/usr/local/go/src/testing/testing.go:1632 +0x230
2025-08-11T12:16:14.9003571Z testing.tRunner.func1()
2025-08-11T12:16:14.9003982Z 	/usr/local/go/src/testing/testing.go:1635 +0x35e
2025-08-11T12:16:14.9004455Z panic({0xb8a560?, 0x86c11a360?})
2025-08-11T12:16:14.9004817Z 	/usr/local/go/src/runtime/panic.go:791 +0x132
2025-08-11T12:16:14.9005319Z reflect.Value.Field({0xb6c980?, 0x86c2a0728?, 0x86c2a0728?}, 0x126b2e0?)
2025-08-11T12:16:14.9005975Z 	/usr/local/go/src/reflect/value.go:1272 +0xcf
2025-08-11T12:16:14.9006868Z github.com/shirou/gopsutil/v4/internal/common.(*decoder).value(0x86c2a06b8, {0xc67860?, 0x86c2a0728?, 0x440?})
2025-08-11T12:16:14.9008233Z 	/root/go/pkg/mod/github.com/shirou/gopsutil/v4@v4.25.7/internal/common/binary.go:475 +0x8be
2025-08-11T12:16:14.9009317Z github.com/shirou/gopsutil/v4/internal/common.Read({0xda1080, 0x86c245680}, {0xda9eb0, 0x1269900}, {0xb58500, 0x86c2a0728})
2025-08-11T12:16:14.9010830Z 	/root/go/pkg/mod/github.com/shirou/gopsutil/v4@v4.25.7/internal/common/binary.go:221 +0x60b
2025-08-11T12:16:14.9011766Z github.com/shirou/gopsutil/v4/process.parseKinfoProc({_, _, _})
2025-08-11T12:16:14.9012569Z 	/root/go/pkg/mod/github.com/shirou/gopsutil/v4@v4.25.7/process/process_bsd.go:74 +0xdc
2025-08-11T12:16:14.9013557Z github.com/shirou/gopsutil/v4/process.ProcessesWithContext({0xda6a10, 0x86c214ee0})
2025-08-11T12:16:14.9014589Z 	/root/go/pkg/mod/github.com/shirou/gopsutil/v4@v4.25.7/process/process_freebsd.go:332 +0x176

[shirou]

Thank you for your information.
I can reproduce on FreeBSD-13.4 amd64 with golang 1.23.0.

--- FAIL: Test_SendSignal (0.00s)
panic: reflect: call of reflect.Value.Field on int32 Value [recovered]
        panic: reflect: call of reflect.Value.Field on int32 Value

goroutine 7 [running]:
testing.tRunner.func1.2({0x615e00, 0x8700121e0})
        /home/shirou/Works/golang/pkg/mod/golang.org/toolchain@v0.0.1-go1.23.0.freebsd-amd64/src/testing/testing.go:1632 +0x230
testing.tRunner.func1()
        /home/shirou/Works/golang/pkg/mod/golang.org/toolchain@v0.0.1-go1.23.0.freebsd-amd64/src/testing/testing.go:1635 +0x35e
panic({0x615e00?, 0x8700121e0?})
        /home/shirou/Works/golang/pkg/mod/golang.org/toolchain@v0.0.1-go1.23.0.freebsd-amd64/src/runtime/panic.go:785 +0x132
reflect.Value.Field({0x60aa00?, 0x870154d40?, 0x870154d40?}, 0x6c57c0?)
        /home/shirou/Works/golang/pkg/mod/golang.org/toolchain@v0.0.1-go1.23.0.freebsd-amd64/src/reflect/value.go:1269 +0xcf
github.com/shirou/gopsutil/v4/internal/common.(*decoder).value(0x87002ecd0, {0x656860?, 0x870154d40?, 0x440?})
        /home/shirou/Works/golang/src/github.com/shirou/gopsutil/internal/common/binary.go:475 +0x8be
github.com/shirou/gopsutil/v4/internal/common.Read({0x6c1660, 0x8700172c0}, {0x6c37f0, 0x868a00}, {0x602a40, 0x870154d40})
        /home/shirou/Works/golang/src/github.com/shirou/gopsutil/internal/common/binary.go:221 +0x60b
github.com/shirou/gopsutil/v4/process.parseKinfoProc({_, _, _})
        /home/shirou/Works/golang/src/github.com/shirou/gopsutil/process/process_bsd.go:74 +0xdc
github.com/shirou/gopsutil/v4/process.(*Process).getKProc(0x87016e000?)
        /home/shirou/Works/golang/src/github.com/shirou/gopsutil/process/process_freebsd.go:358 +0xc5
github.com/shirou/gopsutil/v4/process.(*Process).createTimeWithContext(0xe0?, {0x64c9c0?, 0x87005fea8?})

And you are right. When revert the changes, the test passes.

diff --git a/internal/common/binary.go b/internal/common/binary.go
index da7eb63..11a4fd4 100644
--- a/internal/common/binary.go
+++ b/internal/common/binary.go
@@ -472,7 +472,7 @@ func (d *decoder) value(v reflect.Value) {
                        // but creating the StructField info for each field is
                        // costly (run "go test -bench=ReadStruct" and compare
                        // results when making changes to this code).
-                       if v = v.Field(i); v.CanSet() || t.Field(i).Name != "_" {
+                       if v := v.Field(i); v.CanSet() || t.Field(i).Name != "_" {
                                d.value(v)
                        } else {
                                d.skip(v)
@@ -534,7 +534,7 @@ func (e *encoder) value(v reflect.Value) {
                l := v.NumField()
                for i := 0; i < l; i++ {
                        // see comment for corresponding code in decoder.value()
-                       if v = v.Field(i); v.CanSet() || t.Field(i).Name != "_" {
+                       if v := v.Field(i); v.CanSet() || t.Field(i).Name != "_" {
                                e.value(v)
                        } else {
                                e.skip(v)

I will open a PR to fix and remove the lint. But I will be able to work at least one weeks later.

[sni]

btw, i can recommend the https://github.com/vmactions/freebsd-vm action which allows to run tests here on github on a bsd vm. I can prepare a pull request if you like.

[shirou]

@sni Sorry for the late reply. I’ve opened PR #1907 to fix this issue. Do you have time to take a look? Also, using vmactions/freebsd-vm is a great idea! I would really appreciate it if you could open a PR to add it as a GitHub Action.

[DtxdF]

@sni Sorry for the late reply. I’ve opened PR #1907 to fix this issue. Do you have time to take a look? Also, using vmactions/freebsd-vm is a great idea! I would really appreciate it if you could open a PR to add it as a GitHub Action.

Thank you for fixing this issue!

I tested the patches on my own ports tree to finish the NGINX UI port that depends on gopsutil, and it works!