[PATCH v2 32/59] docs/dyndbg: explain flags parse 1st

[Louis Chauvet]

Le 20/03/2025 à 19:52, Jim Cromie a écrit :
> When writing queries to >control, flags are parsed 1st, since they are
> the only required field, and they require specific compositions.  So
> if the flags draw an error (on those specifics), then keyword errors
> aren't reported.  This can be mildly confusing/annoying, so explain it
> instead.
> 
> cc: linux-doc at vger.kernel.org
> Signed-off-by: Jim Cromie <jim.cromie at gmail.com>

Reviewed-by: Louis Chauvet <louis.chauvet at bootlin.com>

I think this could be merged outside this series.

> ---
>   Documentation/admin-guide/dynamic-debug-howto.rst | 10 ++++++++++
>   1 file changed, 10 insertions(+)
> 
> diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
> index 8e2083605bd7..d2928884c92b 100644
> --- a/Documentation/admin-guide/dynamic-debug-howto.rst
> +++ b/Documentation/admin-guide/dynamic-debug-howto.rst
> @@ -112,6 +112,16 @@ The match-spec's select *prdbgs* from the catalog, upon which to apply
>   the flags-spec, all constraints are ANDed together.  An absent keyword
>   is the same as keyword "*".
>   
> +Note: because the match-spec can be empty, the flags are checked 1st,
> +then the pairs of keyword values.  Flag errs will hide keyword errs:
> +
> +  bash-5.2# ddcmd mod bar +foo
> +  dyndbg: read 13 bytes from userspace
> +  dyndbg: query 0: "mod bar +foo" mod:*
> +  dyndbg: unknown flag 'o'
> +  dyndbg: flags parse failed
> +  dyndbg: processed 1 queries, with 0 matches, 1 errs
> +
>   A match specification is a keyword, which selects the attribute of
>   the callsite to be compared, and a value to compare against.  Possible
>   keywords are:::

-- 
Louis Chauvet, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com