| From | Kamal Mostafa <> | Subject | [PATCH 3.13 008/105] x86, fpu: __restore_xstate_sig()->math_state_restore() needs preempt_disable() | Date | Mon, 27 Oct 2014 11:55:43 -0700 |
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3.13.11.10 -stable review patch. If anyone has any objections, please let me know.
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From: Oleg Nesterov <oleg@redhat.com>
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 <oleg@redhat.com> Link: http://lkml.kernel.org/r/20140902175717.GA21649@redhat.com Reviewed-by: Suresh Siddha <sbsiddha@gmail.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- arch/x86/kernel/xsave.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c index 31f6bfd..f5869fc 100644 --- a/arch/x86/kernel/xsave.c +++ b/arch/x86/kernel/xsave.c @@ -397,8 +397,11 @@ int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size) set_used_math(); } - if (use_eager_fpu()) + if (use_eager_fpu()) { + preempt_disable(); math_state_restore(); + preempt_enable(); + } return err; } else { -- 1.9.1
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