watchdog: Improve initialisation error message and documentation
The error message 'NMI watchdog failed to create perf event...'
does not make it clear that this is a fatal error for the
watchdog. It also currently prints the error value as a
pointer, rather than extracting the error code with PTR_ERR().
Fix that.
Add a note to the description of the 'nowatchdog' kernel
parameter to associate it with this message.
Reported-by: Cesare Leonardi <celeonar@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: 599368@bugs.debian.org
Cc: 608138@bugs.debian.org
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: <stable@kernel.org> # .37.x and later
LKML-Reference: <1294009362.3167.126.camel@localhost>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 6e3c41a..5b08215 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -364,7 +364,8 @@
goto out_save;
}
- printk(KERN_ERR "NMI watchdog failed to create perf event on cpu%i: %p\n", cpu, event);
+ printk(KERN_ERR "NMI watchdog disabled for cpu%i: unable to create perf event: %ld\n",
+ cpu, PTR_ERR(event));
return PTR_ERR(event);
/* success path */