linux-kernel - [PATCH][Rebased for 5.16] x86/fpu/xstate: Fix the ARCH_REQ_XCOMP

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Date:   Tue,  5 Apr 2022 04:04:56 -0700
From:   "Chang S. Bae" <chang.seok.bae@...el.com>
To:     stable@...r.kernel.org, gregkh@...uxfoundation.org
Cc:     yang.zhong@...el.com, bonzini@....org, tglx@...utronix.de,
        linux-kernel@...r.kernel.org, chang.seok.bae@...el.com
Subject: [PATCH][Rebased for 5.16] x86/fpu/xstate: Fix the ARCH_REQ_XCOMP_PERM implementation

From: Yang Zhong <yang.zhong@...el.com>

This is backport for 5.16

Upstream commit 063452fd94d153d4eb38ad58f210f3d37a09cca4

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
[chang: Backport for 5.16]
Signed-off-by: Chang S. Bae <chang.seok.bae@...el.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 d28829403ed0..fc1ab0116f4e 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1626,7 +1626,7 @@ static int __xstate_request_perm(u64 permitted, u64 requested)
 		return ret;
 
 	/* Pairs with the READ_ONCE() in xstate_get_group_perm() */
-	WRITE_ONCE(fpu->perm.__state_perm, requested);
+	WRITE_ONCE(fpu->perm.__state_perm, mask);
 	/* Protected by sighand lock */
 	fpu->perm.__state_size = ksize;
 	fpu->perm.__user_state_size = usize;
-- 
2.17.1