Commit-ID: df24fb859a4e200d9324e2974229fbb7adf00aef
Gitweb: http://git.kernel.org/tip/df24fb859a4e200d9324e2974229fbb7adf00aef
Author: Oleg Nesterov <oleg@xxxxxxxxxx>
AuthorDate: Tue, 2 Sep 2014 19:57:17 +0200
Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
CommitDate: Tue, 2 Sep 2014 14:51:15 -0700
x86, fpu: __restore_xstate_sig()->math_state_restore() needs preempt_disable()
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@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/20140902175717.GA21649@xxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx> # v3.7+
Reviewed-by: Suresh Siddha <sbsiddha@xxxxxxxxx>
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
---
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 cf0b830..4c540c4 100644
--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -400,8 +400,11 @@ 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 {
--
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