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>

diff --git a/tools/testing/selftests/x86/pkey-helpers.h b/tools/testing/selftests/x86/pkey-helpers.h
index 3818f25391c24c34beeb20c2e9f937bdfc9b111a..b3cb7670e02661cd2ab66fd3da98b3940dd44c70 100644 (file)
--- 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);
 }