https://bugs.kde.org/show_bug.cgi?id=451626
--- Comment #2 from Andreas Gerstmayr <andr...@gerstmayr.me> --- (In reply to Mark Wielaard from comment #1) > So there are two issues here: > > - WARNING: unhandled eBPF command 35 > This seems to be BPF_LINK_DETACH, which valgrind indeed doesn't handle. Yep, that's fine so far. I'm more concerned about the error below. > - Syscall param bpf(attr->raw_tracepoint.name) points to unaddressable > byte(s) > Address 0x0 is not stack'd, malloc'd or (recently) free'd > This check is only done for BPF_RAW_TRACEPOINT_OPEN > It isn't immediately clear to me that is is allowed to be NULL. > > Do you happen to have documentation which explains what > BPF_RAW_TRACEPOINT_OPEN does when the name is NULL? Good question :) I looked in the caller, and it's quite explicit about setting the name to NULL: https://github.com/libbpf/libbpf/blob/d6783c28b40e8355d2e3bd4a8141b88da7704f6d/src/libbpf.c#L10491 Then I looked into the syscall on the kernel side (https://github.com/torvalds/linux/blob/56e337f2cf1326323844927a04e9dbce9a244835/kernel/bpf/syscall.c#L3042-L3056) and it goes as far as erroring out if the name is set to anything other than NULL with the following comment: "The attach point for this category of programs should be specified via btf_id during program load." A few lines later tp_name is set to prog->aux->attach_func_name. prog->type is BPF_PROG_TYPE_TRACING in our case, I've verified that in the bpf_program__attach_btf_id function on the libbpf side. So afaics, when using BTF, only the raw_tracepoint.prog_fd should be set. -- You are receiving this mail because: You are watching all bug changes.
