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Subject[PATCH v2 1/2] x86/arch_prctl: Fix the ARCH_REQ_XCOMP_PERM implementation
Date
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 request feature bit to the master bitmask.

Reported-by: Yang Zhong <yang.zhong@intel.com>
Fixes: db8268df0983 ("x86/arch_prctl: Add controls for dynamic XSTATE components")
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
---
Changes from v1:
* Change the mask value only and trim the changelog.
---
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
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