From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Jiri Kosina <jkosina@suse.cz>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Ben Hutchings <ben@decadent.org.uk>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] cpu/speculation: Warn on unsupported mitigations= parameter
Date: Thu, 16 May 2019 12:43:12 -0500 [thread overview]
Message-ID: <20190516174312.f3ipwv4io4tnulnn@treble> (raw)
In-Reply-To: <20190516070935.22546-1-geert@linux-m68k.org>
On Thu, May 16, 2019 at 09:09:35AM +0200, Geert Uytterhoeven wrote:
> Currently, if the user specifies an unsupported mitigation strategy on
> the kernel command line, it will be ignored silently. The code will
> fall back to the default strategy, possibly leaving the system more
> vulnerable than expected.
>
> This may happen due to e.g. a simple typo, or, for a stable kernel
> release, because not all mitigation strategies have been backported.
>
> Inform the user by printing a message.
>
> Fixes: 98af8452945c5565 ("cpu/speculation: Add 'mitigations=' cmdline option")
> Cc: stable@vger.kernel.org
> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
> ---
> kernel/cpu.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/kernel/cpu.c b/kernel/cpu.c
> index f2ef10460698e9ec..8458fda00e6ddb88 100644
> --- a/kernel/cpu.c
> +++ b/kernel/cpu.c
> @@ -2339,6 +2339,9 @@ static int __init mitigations_parse_cmdline(char *arg)
> cpu_mitigations = CPU_MITIGATIONS_AUTO;
> else if (!strcmp(arg, "auto,nosmt"))
> cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT;
> + else
> + pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n",
> + arg);
>
> return 0;
> }
> --
> 2.17.1
>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
--
Josh
next prev parent reply other threads:[~2019-05-16 17:43 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-16 7:09 [PATCH] cpu/speculation: Warn on unsupported mitigations= parameter Geert Uytterhoeven
2019-05-16 7:48 ` Jiri Kosina
2019-05-16 8:16 ` Ingo Molnar
2019-05-16 17:43 ` Josh Poimboeuf [this message]
2019-06-26 15:16 ` [tip:smp/urgent] " tip-bot for Geert Uytterhoeven
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