[tip: x86/urgent] x86/fpu/xstate: Fix the ARCH_REQ_XCOMP_PERM implementation

tip-bot2 for Yang Zhong
2022-03-23T23:31:54Z

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@intel.com>
AuthorDate: Sat, 29 Jan 2022 09:36:46 -08:00
Committer: Thomas Gleixner <tglx@linutronix.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@intel.com>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Paolo Bonzini <bonzini@gnu.org>
Cc: stable@vger.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;