linux-kernel - [tip: x86/urgent] x86/fpu/xstate: Fix the ARCH_REQ_XCOMP

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Message-ID: <164807830122.389.15178914175068421091.tip-bot2@tip-bot2>
Date:   Wed, 23 Mar 2022 23:31:41 -0000
From:   "tip-bot2 for Yang Zhong" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Yang Zhong <yang.zhong@...el.com>,
        "Chang S. Bae" <chang.seok.bae@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Paolo Bonzini <bonzini@....org>, stable@...r.kernel.org,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/urgent] x86/fpu/xstate: Fix the ARCH_REQ_XCOMP_PERM implementation

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     063452fd94d153d4eb38ad58f210f3d37a09cca4
Gitweb:        https://git.kernel.org/tip/063452fd94d153d4eb38ad58f210f3d37a09cca4
Author:        Yang Zhong <yang.zhong@...el.com>
AuthorDate:    Sat, 29 Jan 2022 09:36:46 -08:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Wed, 23 Mar 2022 21:28:34 +01:00

x86/fpu/xstate: Fix the ARCH_REQ_XCOMP_PERM implementation

ARCH_REQ_XCOMP_PERM is supposed to add the requested feature to the
permission bitmap of thread_group_leader()->fpu. But the code overwrites
the bitmap with the requested feature bit only rather than adding it.

Fix the code to add the requested feature bit to the master bitmask.

Fixes: db8268df0983 ("x86/arch_prctl: Add controls for dynamic XSTATE components")
Signed-off-by: Yang Zhong <yang.zhong@...el.com>
Signed-off-by: Chang S. Bae <chang.seok.bae@...el.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Paolo Bonzini <bonzini@....org>
Cc: stable@...r.kernel.org
Link: https://lore.kernel.org/r/20220129173647.27981-2-chang.seok.bae@intel.com

---
 arch/x86/kernel/fpu/xstate.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 7c7824a..dc6d5e9 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1639,7 +1639,7 @@ static int __xstate_request_perm(u64 permitted, u64 requested, bool guest)

 	perm = guest ? &fpu->guest_perm : &fpu->perm;
 	/* Pairs with the READ_ONCE() in xstate_get_group_perm() */
-	WRITE_ONCE(perm->__state_perm, requested);
+	WRITE_ONCE(perm->__state_perm, mask);
 	/* Protected by sighand lock */
 	perm->__state_size = ksize;
 	perm->__user_state_size = usize;