1. 29 Sep, 2020 2 commits
  2. 28 Sep, 2020 10 commits
  3. 26 Sep, 2020 1 commit
    • John Fastabend's avatar
      bpf: Add comment to document BTF type PTR_TO_BTF_ID_OR_NULL · ba5f4cfe
      John Fastabend authored
      The meaning of PTR_TO_BTF_ID_OR_NULL differs slightly from other types
      denoted with the *_OR_NULL type. For example the types PTR_TO_SOCKET
      and PTR_TO_SOCKET_OR_NULL can be used for branch analysis because the
      type PTR_TO_SOCKET is guaranteed to _not_ have a null value.
      
      In contrast PTR_TO_BTF_ID and BTF_TO_BTF_ID_OR_NULL have slightly
      different meanings. A PTR_TO_BTF_TO_ID may be a pointer to NULL value,
      but it is safe to read this pointer in the program context because
      the program context will handle any faults. The fallout is for
      PTR_TO_BTF_ID the verifier can assume reads are safe, but can not
      use the type in branch analysis. Additionally, authors need to be
      extra careful when passing PTR_TO_BTF_ID into helpers. In general
      helpers consuming type PTR_TO_BTF_ID will need to assume it may
      be null.
      
      Seeing the above is not obvious to readers without the back knowledge
      lets add a comment in the type definition.
      
      Editorial comment, as networking and tracing programs get closer
      and more tightly merged we may need to consider a new type that we
      can ensure is non-null for branch analysis and also passing into
      helpers.
      Signed-off-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
      Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      Acked-by: default avatarLorenz Bauer <lmb@cloudflare.com>
      ba5f4cfe
  4. 25 Sep, 2020 16 commits
  5. 24 Sep, 2020 11 commits