[PATCH 4/4] x86, selftests: fix protection keys write() warining

[Dave Hansen <dave.hansen@linux.intel.com>]

From: Dave Hansen <dave.hansen@linux.intel.com>

write() is marked as having a must-check return value.  Check it and
abort if we fail to write an error message from a signal handler.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
---

 b/tools/testing/selftests/x86/pkey-helpers.h |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff -puN tools/testing/selftests/x86/pkey-helpers.h~x86-selftests-protection-keys-write-warning tools/testing/selftests/x86/pkey-helpers.h
--- a/tools/testing/selftests/x86/pkey-helpers.h~x86-selftests-protection-keys-write-warning	2017-11-10 15:29:29.240207938 -0800
+++ b/tools/testing/selftests/x86/pkey-helpers.h	2017-11-10 15:29:29.244207938 -0800
@@ -30,6 +30,7 @@ static inline void sigsafe_printf(const
 	if (!dprint_in_signal) {
 		vprintf(format, ap);
 	} else {
+		int ret;
 		int len = vsnprintf(dprint_in_signal_buffer,
 				    DPRINT_IN_SIGNAL_BUF_SIZE,
 				    format, ap);
@@ -39,7 +40,9 @@ static inline void sigsafe_printf(const
 		 */
 		if (len > DPRINT_IN_SIGNAL_BUF_SIZE)
 			len = DPRINT_IN_SIGNAL_BUF_SIZE;
-		write(1, dprint_in_signal_buffer, len);
+		ret = write(1, dprint_in_signal_buffer, len);
+		if (ret < 0)
+			abort();
 	}
 	va_end(ap);
 }
_