[Bug target/119731] New: bpf verifier failure with systemd's restrict-fs

[sjames at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119731

            Bug ID: 119731
           Summary: bpf verifier failure with systemd's restrict-fs
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sjames at gcc dot gnu.org
  Target Milestone: ---
            Target: bpf

Created attachment 61075
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=61075&action=edit
restrict-fs-clang.bpf.i.xz

Been discussing this with Cupertino today -- filing a bug to put attachments
in.

systemd-257.5's bpf-restrict-fs fails to load, in dmesg:
```
[ 7641.179562] systemd[1]: bpf-restrict-fs: Failed to load BPF object: Invalid
argument
```

To build with both GCC and Clang for comparison:
```
#!/bin/bash
set -x

build_gcc() {
        /usr/bin/bpf-unknown-none-gcc -std=gnu11 -fno-stack-protector
-fno-ssa-phiopt -O2 -mcpu=v3 -mco-re -gbtf \
                -mlittle-endian \
                restrict-fs-gcc.bpf.i \
                -o restrict-fs-gcc.bpf.unstripped.o
}

build_clang() {
        /usr/lib/llvm/19/bin/clang -std=gnu11
-Wno-compare-distinct-pointer-types -fno-stack-protector -O2 -target bpf -g \
                -c restrict-fs-clang.bpf.i \
                -o restrict-fs-clang.bpf.unstripped.o
}

build_gcc
build_clang
```