feat(ebpf): use bpf_task_pt_regs when available #4238
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Tracee's `get_task_pt_regs` function mimics the logic of this helper, but relies on assuming some values defined in the kernel. This commit changes this function to use the helper if it is available. This helper must receive a task_struct with BTF info obtained from `bpf_get_current_task_btf`. From my experimentation, the verifier cannot determine whether a task_struct contains BTF info if it was stored outside of the stack. This means that this function cannot acutally retrieve the registers of any task except for the current one. The function name was changed to reflect this requirement, and it no longer receives a task_struct as a parameter. Thanks @oshaked1 for writing this commit!
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Thanks @oshaked1 for writing this commit!
1. Explain what the PR does
Tracee's
get_task_pt_regsfunction mimics the logic of this helper, but relies on assuming some values defined in the kernel. This commit changes this function to use the helper if it is available. This helper must receive a task_struct with BTF info obtained frombpf_get_current_task_btf. From my experimentation, the verifier cannot determine whether a task_struct contains BTF info if it was stored outside of the stack. This means that this function cannot acutally retrieve the registers of any task except for the current one. The function name was changed to reflect this requirement, and it no longer receives a task_struct as a parameter.2. Explain how to test it
./tracee
3. Other comments
Closes #4239