linux-kernel - Re: [PATCH AUTOSEL 5.7 52/60] dyndbg: prefer declarative init in caller, to memset in callee

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Date:   Tue, 11 Aug 2020 07:13:32 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Sasha Levin <sashal@...nel.org>
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Jim Cromie <jim.cromie@...il.com>, jbaron@...mai.com
Subject: Re: [PATCH AUTOSEL 5.7 52/60] dyndbg: prefer declarative init in
 caller, to memset in callee

On Mon, Aug 10, 2020 at 03:10:20PM -0400, Sasha Levin wrote:
> From: Jim Cromie <jim.cromie@...il.com>
> 
> [ Upstream commit 9c9d0acbe2793315fa6945a19685ad2a51fb281b ]
> 
> ddebug_exec_query declares an auto var, and passes it to
> ddebug_parse_query, which memsets it before using it.  Drop that
> memset, instead initialize the variable in the caller; let the
> compiler decide how to do it.
> 
> Acked-by: <jbaron@...mai.com>
> Signed-off-by: Jim Cromie <jim.cromie@...il.com>
> Link: https://lore.kernel.org/r/20200719231058.1586423-10-jim.cromie@gmail.com
> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Signed-off-by: Sasha Levin <sashal@...nel.org>
> ---
>  lib/dynamic_debug.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
> index e3755d1f74bd2..4f0bd560478f7 100644
> --- a/lib/dynamic_debug.c
> +++ b/lib/dynamic_debug.c
> @@ -327,7 +327,6 @@ static int ddebug_parse_query(char *words[], int nwords,
>  		pr_err("expecting pairs of match-spec <value>\n");
>  		return -EINVAL;
>  	}
> -	memset(query, 0, sizeof(*query));
>  
>  	if (modname)
>  		/* support $modname.dyndbg=<multiple queries> */
> @@ -445,7 +444,7 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
>  static int ddebug_exec_query(char *query_string, const char *modname)
>  {
>  	unsigned int flags = 0, mask = 0;
> -	struct ddebug_query query;
> +	struct ddebug_query query = {};
>  #define MAXWORDS 9
>  	int nwords, nfound;
>  	char *words[MAXWORDS];
> -- 
> 2.25.1
> 

There's no need for this in stable kernels, please drop it from
everywhere.

thanks,

greg k-h