x86, fpu: check __clear_user() return value

fix warning:

  arch/x86/kernel/xsave.c: In function ‘save_i387_xstate’:
  arch/x86/kernel/xsave.c:98: warning: ignoring return value of ‘__clear_user’, declared with attribute warn_unused_result

check the return value and act on it. We should not be ignoring faults
at this point.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 1 deletions

diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
index 2f98323716d..9abac8a9d82 100644
--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -95,7 +95,9 @@ int save_i387_xstate(void __user *buf)
                  * Start with clearing the user buffer. This will present a
                  * clean context for the bytes not touched by the fxsave/xsave.
                  */
-                __clear_user(buf, sig_xstate_size);
+                err = __clear_user(buf, sig_xstate_size);
+                if (err)
+                        return err;
 
                 if (task_thread_info(tsk)->status & TS_XSAVE)
                         err = xsave_user(buf);