Re: [PATCH v2] tracetool: also strip %l and %ll from systemtap format strings

[Laurent Vivier <lvivier@redhat.com>]

On 06/01/2021 14:02, Daniel P. Berrangé wrote:
> All variables are 64-bit and so %l / %ll are not required, and the
> latter is actually invalid:
> 
>   $ sudo stap -e 'probe begin{printf ("BEGIN")}'  -I .
>   parse error: invalid or missing conversion specifier
>           saw: operator ',' at ./qemu-system-x86_64-log.stp:15118:101
>        source:     printf("%d@%d vhost_vdpa_set_log_base dev: %p base: 0x%x size: %llu
> refcnt: %d fd: %d log: %p\n", pid(), gettimeofday_ns(), dev, base, size, refcnt, fd, log)
> 
>                        ^
> 
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
>  scripts/tracetool/format/log_stap.py | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> In v2:
> 
>  - Change existing logic that stripped %z to handle %l/%ll too
> 
> diff --git a/scripts/tracetool/format/log_stap.py b/scripts/tracetool/format/log_stap.py
> index b486beb672..fac911a0f4 100644
> --- a/scripts/tracetool/format/log_stap.py
> +++ b/scripts/tracetool/format/log_stap.py
> @@ -77,7 +77,12 @@ def c_fmt_to_stap(fmt):
>      elif state == STATE_LITERAL:
>          bits.append(literal)
>  
> -    fmt = re.sub("%(\d*)z(x|u|d)", "%\\1\\2", "".join(bits))
> +    # All variables in systemtap are 64-bit in size
> +    # The "%l" integer size qualifier is thus redundant
> +    # and "%ll" is not valid at all. Simiarly the size_t
> +    # based "%z" size qualifier is not valid. We just
> +    # strip all size qualifiers for sanity.
> +    fmt = re.sub("%(\d*)(l+|z)(x|u|d)", "%\\1\\3", "".join(bits))
>      return fmt
>  
>  def generate(events, backend, group):
> 

Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Tested-by: Laurent Vivier <lvivier@redhat.com>