watchdog: Reduce message verbosity

Code is emitting the following error message during boot on systems
without PMU hardware support while probing NMI capability.

 NMI watchdog: Perf event create on CPU 0 failed with -2

This error is emitted as the perf subsystem returns -ENOENT due to lack of
PMUs in the system.

It is followed by the warning that NMI watchdog is disabled:

  NMI watchdog: Perf NMI watchdog permanently disabled

While NMI disabled information is useful for ordinary users, seeing a PERF
event create failed with error code -2 is not.

Reduce the message severity to debug so that if debugging is still possible
in case the error code returned by perf is required for analysis.

Signed-off-by: Sinan Kaya <okaya@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Don Zickus <dzickus@redhat.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=599368
Link: https://lkml.kernel.org/r/20180803060943.2643-1-okaya@kernel.org

diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c
index e449a23e9d5982e9069849a5f370c454dfe35383..1f7020d65d0aa2963708d3e44057e08ce2305ead 100644 (file)
--- a/kernel/watchdog_hld.c
+++ b/kernel/watchdog_hld.c
@@ -175,8 +175,8 @@ static int hardlockup_detector_event_create(void)
        evt = perf_event_create_kernel_counter(wd_attr, cpu, NULL,
                                               watchdog_overflow_callback, NULL);
        if (IS_ERR(evt)) {
-               pr_info("Perf event create on CPU %d failed with %ld\n", cpu,
-                       PTR_ERR(evt));
+               pr_debug("Perf event create on CPU %d failed with %ld\n", cpu,
+                        PTR_ERR(evt));
                return PTR_ERR(evt);
        }
        this_cpu_write(watchdog_ev, evt);