linux-kernel - Re: [PATCH] fault-inject: Avoid call to random32() if fault injection is disabled

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] [day] [month] [year] [list]

Date:	Fri, 1 Jun 2012 21:38:13 +0900
From:	Akinobu Mita <akinobu.mita@...il.com>
To:	Anton Blanchard <anton@...ba.org>
Cc:	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] fault-inject: Avoid call to random32() if fault injection
 is disabled

2012/6/1 Anton Blanchard <anton@...ba.org>:
>
> After enabling CONFIG_FAILSLAB I noticed random32 in profiles even
> if slub fault injection wasn't enabled at runtime.
>
> should_fail forces a comparison against random32() even if
> probability is 0:
>
>        if (attr->probability <= random32() % 100)
>                return false;
>
> Add a check up front for probability == 0 and avoid all of the more
> complicated checks.
>
> Signed-off-by: Anton Blanchard <anton@...ba.org>
> ---
>
> Index: linux-build/lib/fault-inject.c
> ===================================================================
> --- linux-build.orig/lib/fault-inject.c 2012-02-11 21:22:32.303459860 +1100
> +++ linux-build/lib/fault-inject.c      2012-02-11 22:38:10.470977505 +1100
> @@ -101,6 +101,10 @@ static inline bool fail_stacktrace(struc
>
>  bool should_fail(struct fault_attr *attr, ssize_t size)
>  {
> +       /* No need to check any other properties if the probability is 0 */
> +       if (attr->probability == 0)
> +               return false;
> +
>        if (attr->task_filter && !fail_task(attr, current))
>                return false;
>

Looks good to me.

Acked-by: Akinobu Mita <akinobu.mita@...il.com>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/