1. 13 Jan, 2018 2 commits
    • Masami Hiramatsu's avatar
      error-injection: Add injectable error types · 663faf9f
      Masami Hiramatsu authored
      Add injectable error types for each error-injectable function.
      
      One motivation of error injection test is to find software flaws,
      mistakes or mis-handlings of expectable errors. If we find such
      flaws by the test, that is a program bug, so we need to fix it.
      
      But if the tester miss input the error (e.g. just return success
      code without processing anything), it causes unexpected behavior
      even if the caller is correctly programmed to handle any errors.
      That is not what we want to test by error injection.
      
      To clarify what type of errors the caller must expect for each
      injectable function, this introduces injectable error types:
      
       - EI_ETYPE_NULL : means the function will return NULL if it
      		    fails. No ERR_PTR, just a NULL.
       - EI_ETYPE_ERRNO : means the function will return -ERRNO
      		    if it fails.
       - EI_ETYPE_ERRNO_NULL : means the function will return -ERRNO
      		       (ERR_PTR) or NULL.
      
      ALLOW_ERROR_INJECTION() macro is expanded to get one of
      NULL, ERRNO, ERRNO_NULL to record the error type for
      each function. e.g.
      
       ALLOW_ERROR_INJECTION(open_ctree, ERRNO)
      
      This error types are shown in debugfs as below.
      
        ====
        / # cat /sys/kernel/debug/error_injection/list
        open_ctree [btrfs]	ERRNO
        io_ctl_init [btrfs]	ERRNO
        ====
      Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
      Reviewed-by: default avatarJosef Bacik <jbacik@fb.com>
      Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      663faf9f
    • Masami Hiramatsu's avatar
      error-injection: Separate error-injection from kprobe · 540adea3
      Masami Hiramatsu authored
      Since error-injection framework is not limited to be used
      by kprobes, nor bpf. Other kernel subsystems can use it
      freely for checking safeness of error-injection, e.g.
      livepatch, ftrace etc.
      So this separate error-injection framework from kprobes.
      
      Some differences has been made:
      
      - "kprobe" word is removed from any APIs/structures.
      - BPF_ALLOW_ERROR_INJECTION() is renamed to
        ALLOW_ERROR_INJECTION() since it is not limited for BPF too.
      - CONFIG_FUNCTION_ERROR_INJECTION is the config item of this
        feature. It is automatically enabled if the arch supports
        error injection feature for kprobe or ftrace etc.
      Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
      Reviewed-by: default avatarJosef Bacik <jbacik@fb.com>
      Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      540adea3