x86/pkeys/selftests: Fix protection keys write() warning

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>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20171111001232.94813E58@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/tools/testing/selftests/x86/pkey-helpers.h b/tools/testing/selftests/x86/pkey-helpers.h
index 3818f25391c2..b3cb7670e026 100644
--- a/tools/testing/selftests/x86/pkey-helpers.h
+++ b/tools/testing/selftests/x86/pkey-helpers.h
@@ -30,6 +30,7 @@ static inline void sigsafe_printf(const char *format, ...)
         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 char *format, ...)
                  */
                 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);
 }