From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: fix PTRACE_SETVFPREGS on SMP systems
Date: Tue, 31 May 2016 19:20:46 +0100 [thread overview]
Message-ID: <20160531182045.GZ24936@arm.com> (raw)
In-Reply-To: <E1b7oBz-0005wE-1t@rmk-PC.armlinux.org.uk>
On Tue, May 31, 2016 at 07:15:03PM +0100, Russell King wrote:
> PTRACE_SETVFPREGS fails to properly mark the VFP register set to be
> reloaded, because it undoes one of the effects of vfp_flush_hwstate().
>
> Specifically vfp_flush_hwstate() sets thread->vfpstate.hard.cpu to
> an invalid CPU number, but vfp_set() overwrites this with the original
> CPU number, thereby rendering the hardware state as apparently "valid",
> even though the software state is more recent.
>
> Fix this by reverting the previous change.
>
> Cc: <stable@vger.kernel.org>
> Fixes: 8130b9d7b9d8 ("ARM: 7308/1: vfp: flush thread hwstate before copying ptrace registers")
> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
> ---
> Will, please ack this.
Acked-by: Will Deacon <will.deacon@arm.com>
Will
>
> arch/arm/kernel/ptrace.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
> index ef9119f7462e..4d9375814b53 100644
> --- a/arch/arm/kernel/ptrace.c
> +++ b/arch/arm/kernel/ptrace.c
> @@ -733,8 +733,8 @@ static int vfp_set(struct task_struct *target,
> if (ret)
> return ret;
>
> - vfp_flush_hwstate(thread);
> thread->vfpstate.hard = new_vfp;
> + vfp_flush_hwstate(thread);
>
> return 0;
> }
> --
> 2.1.0
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
prev parent reply other threads:[~2016-05-31 18:20 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-31 18:15 [PATCH] ARM: fix PTRACE_SETVFPREGS on SMP systems Russell King
2016-05-31 18:20 ` Will Deacon [this message]
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