linux-kernel - Re: [PATCH v3 15/20] ratelimit: Warn if ->interval or ->burst are negative

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aBDEtcmUEhiL5-zO@pathway.suse.cz>
Date: Tue, 29 Apr 2025 14:23:17 +0200
From: Petr Mladek <pmladek@...e.com>
To: "Paul E. McKenney" <paulmck@...nel.org>
Cc: linux-kernel@...r.kernel.org, kernel-team@...a.com,
	Andrew Morton <akpm@...ux-foundation.org>,
	Kuniyuki Iwashima <kuniyu@...zon.com>,
	Mateusz Guzik <mjguzik@...il.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	John Ogness <john.ogness@...utronix.de>,
	Sergey Senozhatsky <senozhatsky@...omium.org>,
	Jon Pan-Doh <pandoh@...gle.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Karolina Stolarek <karolina.stolarek@...cle.com>
Subject: Re: [PATCH v3 15/20] ratelimit: Warn if ->interval or ->burst are
 negative

On Thu 2025-04-24 17:28:21, Paul E. McKenney wrote:
> From: Petr Mladek <pmladek@...e.com>
> 
> Currently, ___ratelimit() treats a negative ->interval or ->burst as
> if it was zero, but this is an accident of the current implementation.
> Therefore, splat in this case, which might have the benefit of detecting
> use of uninitialized ratelimit_state structures on the one hand or easing
> addition of new features on the other.
> 
> Link: https://lore.kernel.org/all/fbe93a52-365e-47fe-93a4-44a44547d601@paulmck-laptop/
> Link: https://lore.kernel.org/all/20250423115409.3425-1-spasswolf@web.de/
> Signed-off-by: Petr Mladek <pmladek@...e.com>
> Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
> Cc: Andrew Morton <akpm@...ux-foundation.org>
> Cc: Kuniyuki Iwashima <kuniyu@...zon.com>
> Cc: Mateusz Guzik <mjguzik@...il.com>
> Cc: Steven Rostedt <rostedt@...dmis.org>
> Cc: John Ogness <john.ogness@...utronix.de>
> Cc: Sergey Senozhatsky <senozhatsky@...omium.org>
> ---
>  lib/ratelimit.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/lib/ratelimit.c b/lib/ratelimit.c
> index 4f5d8fb6919f7..63efb1191d71a 100644
> --- a/lib/ratelimit.c
> +++ b/lib/ratelimit.c
> @@ -40,6 +40,7 @@ int ___ratelimit(struct ratelimit_state *rs, const char *func)
>  	 * says always limit.
>  	 */
>  	if (interval <= 0 || burst <= 0) {
> +		WARN_ONCE(interval < 0 || burst < 0, "Negative interval (%d) or burst (%d): Uninitialized ratelimit_state structure?\n", interval, burst);

Just for record, I agree with having this patch in this form
in this series.

That said, I think that we should warn even about using zero
initialized structure in the long term because of a possible use of
to-be-initialized spin lock. But it would require fixing
existing users and it is beyond scope of this patchset.
It is related to the discussion at
https://lore.kernel.org/r/aA-f0jpBBbdfsmn7@pathway.suse.cz .

Best Regards,
Petr