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Date:   Mon, 22 Mar 2021 14:00:43 -0400
From:   Richard Guy Briggs <rgb@redhat.com>
To:     Arnd Bergmann <arnd@kernel.org>
Cc:     Paul Moore <paul@paul-moore.com>, Eric Paris <eparis@redhat.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Jules Irenge <jbi.octave@gmail.com>, linux-audit@redhat.com,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] [v2] audit: avoid -Wempty-body warning
Message-ID: <20210322180043.GP3141668@madcap2.tricolour.ca>
References: <20210322162807.679370-1-arnd@kernel.org>
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On 2021-03-22 17:27, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> gcc warns about an empty statement when audit_remove_mark is defined to
> nothing:
> 
> kernel/auditfilter.c: In function 'audit_data_to_entry':
> kernel/auditfilter.c:609:51: error: suggest braces around empty body in an 'if' statement [-Werror=empty-body]
>   609 |                 audit_remove_mark(entry->rule.exe); /* that's the template one */
>       |                                                   ^
> 
> Change the macros to use the usual "do { } while (0)" instead, and change a
> few more that were (void)0, for consistency.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Acked-by: Richard Guy Briggs <rgb@redhat.com>

> ---
> v2: convert two more macros
> ---
>  kernel/audit.h | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/kernel/audit.h b/kernel/audit.h
> index 3b9c0945225a..1522e100fd17 100644
> --- a/kernel/audit.h
> +++ b/kernel/audit.h
> @@ -292,8 +292,8 @@ extern void audit_filter_inodes(struct task_struct *tsk,
>  extern struct list_head *audit_killed_trees(void);
>  #else /* CONFIG_AUDITSYSCALL */
>  #define auditsc_get_stamp(c, t, s) 0
> -#define audit_put_watch(w) {}
> -#define audit_get_watch(w) {}
> +#define audit_put_watch(w) do { } while (0)
> +#define audit_get_watch(w) do { } while (0)
>  #define audit_to_watch(k, p, l, o) (-EINVAL)
>  #define audit_add_watch(k, l) (-EINVAL)
>  #define audit_remove_watch_rule(k) BUG()
> @@ -302,8 +302,8 @@ extern struct list_head *audit_killed_trees(void);
>  
>  #define audit_alloc_mark(k, p, l) (ERR_PTR(-EINVAL))
>  #define audit_mark_path(m) ""
> -#define audit_remove_mark(m)
> -#define audit_remove_mark_rule(k)
> +#define audit_remove_mark(m) do { } while (0)
> +#define audit_remove_mark_rule(k) do { } while (0)
>  #define audit_mark_compare(m, i, d) 0
>  #define audit_exe_compare(t, m) (-EINVAL)
>  #define audit_dupe_exe(n, o) (-EINVAL)
> @@ -311,8 +311,8 @@ extern struct list_head *audit_killed_trees(void);
>  #define audit_remove_tree_rule(rule) BUG()
>  #define audit_add_tree_rule(rule) -EINVAL
>  #define audit_make_tree(rule, str, op) -EINVAL
> -#define audit_trim_trees() (void)0
> -#define audit_put_tree(tree) (void)0
> +#define audit_trim_trees() do { } while (0)
> +#define audit_put_tree(tree) do { } while (0)
>  #define audit_tag_tree(old, new) -EINVAL
>  #define audit_tree_path(rule) ""	/* never called */
>  #define audit_kill_trees(context) BUG()
> -- 
> 2.29.2
> 

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635