From: David Vrabel <dvrabel@cantab.net>
To: Tim Gardner <tim.gardner@canonical.com>
Cc: linux-kernel@vger.kernel.org,
Jeremy Fitzhardinge <jeremy@goop.org>,
xen-devel@lists.xensource.com,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
x86@kernel.org, stable@vger.kernel.org,
virtualization@lists.linux-foundation.org,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [Xen-devel] [PATCH linux-next] xen/multicall: xen_mc_callback(): avoid buffer overflow
Date: Fri, 08 Feb 2013 21:13:53 +0000 [thread overview]
Message-ID: <51156A91.5070801@cantab.net> (raw)
In-Reply-To: <1360355677-52442-1-git-send-email-tim.gardner@canonical.com>
On 08/02/2013 20:34, Tim Gardner wrote:
> This buffer overflow was introduced with 91e0c5f3dad47838cb2ecc1865ce789a0b7182b1
> (2.6.24).
There's no buffer overflow here. xen_mc_flush() resets b->cbidx.
David
> arch/x86/xen/multicalls.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/xen/multicalls.c b/arch/x86/xen/multicalls.c
> index 0d82003..5270407 100644
> --- a/arch/x86/xen/multicalls.c
> +++ b/arch/x86/xen/multicalls.c
> @@ -195,9 +195,10 @@ void xen_mc_callback(void (*fn)(void *), void *data)
> struct mc_buffer *b = &__get_cpu_var(mc_buffer);
> struct callback *cb;
>
> - if (b->cbidx == MC_BATCH) {
> + if (b->cbidx >= MC_BATCH) {
> trace_xen_mc_flush_reason(XEN_MC_FL_CALLBACK);
> xen_mc_flush();
> + return;
> }
>
> trace_xen_mc_callback(fn, data);
>
WARNING: multiple messages have this Message-ID (diff)
From: David Vrabel <dvrabel@cantab.net>
To: Tim Gardner <tim.gardner@canonical.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
xen-devel@lists.xensource.com,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org,
virtualization@lists.linux-foundation.org,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH linux-next] xen/multicall: xen_mc_callback(): avoid buffer overflow
Date: Fri, 08 Feb 2013 21:13:53 +0000 [thread overview]
Message-ID: <51156A91.5070801@cantab.net> (raw)
In-Reply-To: <1360355677-52442-1-git-send-email-tim.gardner@canonical.com>
On 08/02/2013 20:34, Tim Gardner wrote:
> This buffer overflow was introduced with 91e0c5f3dad47838cb2ecc1865ce789a0b7182b1
> (2.6.24).
There's no buffer overflow here. xen_mc_flush() resets b->cbidx.
David
> arch/x86/xen/multicalls.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/xen/multicalls.c b/arch/x86/xen/multicalls.c
> index 0d82003..5270407 100644
> --- a/arch/x86/xen/multicalls.c
> +++ b/arch/x86/xen/multicalls.c
> @@ -195,9 +195,10 @@ void xen_mc_callback(void (*fn)(void *), void *data)
> struct mc_buffer *b = &__get_cpu_var(mc_buffer);
> struct callback *cb;
>
> - if (b->cbidx == MC_BATCH) {
> + if (b->cbidx >= MC_BATCH) {
> trace_xen_mc_flush_reason(XEN_MC_FL_CALLBACK);
> xen_mc_flush();
> + return;
> }
>
> trace_xen_mc_callback(fn, data);
>
next prev parent reply other threads:[~2013-02-08 22:22 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-08 20:34 [PATCH linux-next] xen/multicall: xen_mc_callback(): avoid buffer overflow Tim Gardner
2013-02-08 21:13 ` David Vrabel [this message]
2013-02-08 21:13 ` David Vrabel
2013-02-08 21:13 ` [Xen-devel] " David Vrabel
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