[PERF] Optimize struct boundaries and bounds checking parameters in sentinel_bpf.c

[Jean-Regis-M]

Description

Our eBPF telemetry hooks intercepting file and sys_execve loops are verified by the Linux Kernel prior to loading. To improve efficiency and avoid CPU caching misalignment across heterogeneous worker node infrastructures, we would like to enforce explicit 8-byte boundaries on all kernel trace payload events.

Proposed Scope

1. Audit structures defined inside sentinel_common.h and ensure 32-bit and 64-bit alignment patterns prevent memory footprint padding issues across runtime limits.
2. Confirm the placement of __attribute__((packed)) directives on all communication payloads.
3. Review bounds checks immediately preceding critical memory read helpers like bpf_probe_read_user_str or bpf_probe_read_kernel_str to verify the verifier is fully informed of bounds layout definitions.

Expected Files to Modify

• sentinel_common.h or sentinel_bpf.c in kernel bytecode targets.

Verification Steps

• Run native compiler scripts and confirm compiler symbols map output cleanly.
• Ensure the bytecode successfully passes the local eBPF loader verification checks and does not lead to loading errors.