This is a note to let you know that I've just added the patch titled

    x86, fpu: __restore_xstate_sig()->math_state_restore() needs 
preempt_disable()

to the 3.17-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     x86-fpu-__restore_xstate_sig-math_state_restore-needs-preempt_disable.patch
and it can be found in the queue-3.17 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From df24fb859a4e200d9324e2974229fbb7adf00aef Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <[email protected]>
Date: Tue, 2 Sep 2014 19:57:17 +0200
Subject: x86, fpu: __restore_xstate_sig()->math_state_restore() needs 
preempt_disable()

From: Oleg Nesterov <[email protected]>

commit df24fb859a4e200d9324e2974229fbb7adf00aef upstream.

Add preempt_disable() + preempt_enable() around math_state_restore() in
__restore_xstate_sig(). Otherwise __switch_to() after __thread_fpu_begin()
can overwrite fpu->state we are going to restore.

Signed-off-by: Oleg Nesterov <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Reviewed-by: Suresh Siddha <[email protected]>
Signed-off-by: H. Peter Anvin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 arch/x86/kernel/xsave.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -402,8 +402,11 @@ int __restore_xstate_sig(void __user *bu
                        set_used_math();
                }
 
-               if (use_eager_fpu())
+               if (use_eager_fpu()) {
+                       preempt_disable();
                        math_state_restore();
+                       preempt_enable();
+               }
 
                return err;
        } else {


Patches currently in stable-queue which might be from [email protected] are

queue-3.17/x86-fpu-__restore_xstate_sig-math_state_restore-needs-preempt_disable.patch
queue-3.17/x86-fpu-shift-drop_init_fpu-from-save_xstate_sig-to-handle_signal.patch
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