[PATCH 5.16 274/285] x86/fpu/xstate: Fix the ARCH_REQ_XCOMP_PERM implementation

Greg Kroah-Hartman
2022-04-12T08:11:08Z

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

commit 063452fd94d153d4eb38ad58f210f3d37a09cca4 upstream.

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
[chang: Backport for 5.16]
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/fpu/xstate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1626,7 +1626,7 @@ static int __xstate_request_perm(u64 per
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;