From: Dave Hansen <dave.hansen@linux.intel.com>
To: brgerst@gmail.com, bp@alien8.de, tglx@linutronix.de,
quentin.casasnovas@oracle.com, oleg@redhat.com,
torvalds@linux-foundation.org, linux-kernel@vger.kernel.org,
dvlasenk@redhat.com, mingo@kernel.org, haokexin@gmail.com,
hpa@zytor.com, fenghua.yu@intel.com, jpoimboe@redhat.com,
peterz@infradead.org, riel@redhat.com, yu-cheng.yu@intel.com,
luto@kernel.org
Subject: Re: [tip:x86/urgent] x86/fpu: Set the xcomp_bv when we fake up a XSAVES area
Date: Tue, 14 Feb 2017 08:47:42 -0800 [thread overview]
Message-ID: <fd2c48b4-431b-9ae5-90e2-459cd0f7c2a4@linux.intel.com> (raw)
In-Reply-To: <tip-4c833368f0bf748d4147bf301b1f95bc8eccb3c0@git.kernel.org>
On 01/23/2017 01:43 AM, tip-bot for Kevin Hao wrote:
> diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
> index 1d77704..e287b90 100644
> --- a/arch/x86/kernel/fpu/xstate.c
> +++ b/arch/x86/kernel/fpu/xstate.c
> @@ -1070,6 +1070,7 @@ int copyin_to_xsaves(const void *kbuf, const void __user *ubuf,
> * Add back in the features that came in from userspace:
> */
> xsave->header.xfeatures |= xfeatures;
> + xsave->header.xcomp_bv = XCOMP_BV_COMPACTED_FORMAT | xsave->header.xfeatures;
FYI, this commit bit me today. If userspace happens to have bits clear
in the 'xfeatures' field, this will *CLEAR* bits in xcomp_bv, changing
the format of the XSAVE buffer, and breaking anything that looks at the
buffer that doesn't use the instructions.
Yu-cheng's dffba9a31c commit removed this line and fixed it up, but this
might bite someone who is bisecting.
prev parent reply other threads:[~2017-02-14 16:48 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-22 8:50 [PATCH] x86/fpu: set " Kevin Hao
2017-01-23 8:28 ` [tip:x86/urgent] x86/fpu: Set " tip-bot for Kevin Hao
2017-01-23 15:36 ` Dave Hansen
2017-01-23 16:55 ` Yu-cheng Yu
2017-01-23 17:23 ` Dave Hansen
2017-01-23 20:57 ` Yu-cheng Yu
2017-01-23 21:10 ` Dave Hansen
2017-01-23 21:16 ` Yu-cheng Yu
2017-01-23 21:28 ` Dave Hansen
2017-01-24 0:14 ` Kevin Hao
2017-01-24 0:53 ` Dave Hansen
2017-01-24 1:50 ` Kevin Hao
2017-01-24 2:01 ` Dave Hansen
2017-01-24 2:09 ` Kevin Hao
2017-01-24 2:38 ` Dave Hansen
2017-01-24 5:18 ` Kevin Hao
2017-01-24 8:08 ` Ingo Molnar
2017-01-23 9:43 ` tip-bot for Kevin Hao
2017-02-14 16:47 ` Dave Hansen [this message]
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