| Message ID | 1407768567-171794-4-git-send-email-dzickus@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
* Don Zickus <dzickus@redhat.com> wrote: > From: Ulrich Obergfell <uobergfe@redhat.com> > > This patch avoids printing the message 'enabled on all CPUs, ...' > multiple times. For example, the issue can occur in the following > scenario: > > 1) watchdog_nmi_enable() fails to enable PMU counters and sets > cpu0_err. > > 2) 'echo [0|1] > /proc/sys/kernel/nmi_watchdog' is executed to > disable and re-enable the watchdog mechanism 'on the fly'. > > 3) If watchdog_nmi_enable() succeeds to enable PMU counters, each > CPU will print the message because step1 left behind a non-zero > cpu0_err. > > if (!IS_ERR(event)) { > if (cpu == 0 || cpu0_err) > pr_info("enabled on all CPUs, ...") > > The patch avoids this by clearing cpu0_err in watchdog_nmi_disable(). > > Signed-off-by: Ulrich Obergfell <uobergfe@redhat.com> > Signed-off-by: Andrew Jones <drjones@redhat.com> > Signed-off-by: Don Zickus <dzickus@redhat.com> > --- > kernel/watchdog.c | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/kernel/watchdog.c b/kernel/watchdog.c > index 6d0a891..0838685 100644 > --- a/kernel/watchdog.c > +++ b/kernel/watchdog.c > @@ -522,6 +522,9 @@ static void watchdog_nmi_disable(unsigned int cpu) > /* should be in cleanup, but blocks oprofile */ > perf_event_release_kernel(event); > } > + if (cpu == 0) > + /* watchdog_nmi_enable() expects this to be zero initially. */ > + cpu0_err = 0; Looks good except a small detail: two-line blocks need curly braces too, even if it's just a single C statement. I've fixed this up in the commit. thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
* Don Zickus <dzickus@redhat.com> wrote: > --- a/kernel/watchdog.c > +++ b/kernel/watchdog.c > @@ -522,6 +522,9 @@ static void watchdog_nmi_disable(unsigned int cpu) > /* should be in cleanup, but blocks oprofile */ > perf_event_release_kernel(event); > } > + if (cpu == 0) > + /* watchdog_nmi_enable() expects this to be zero initially. */ > + cpu0_err = 0; > return; > } While at it I also removed the stray 'return;'. Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Aug 18, 2014 at 11:07:57AM +0200, Ingo Molnar wrote: > > * Don Zickus <dzickus@redhat.com> wrote: > > > --- a/kernel/watchdog.c > > +++ b/kernel/watchdog.c > > @@ -522,6 +522,9 @@ static void watchdog_nmi_disable(unsigned int cpu) > > /* should be in cleanup, but blocks oprofile */ > > perf_event_release_kernel(event); > > } > > + if (cpu == 0) > > + /* watchdog_nmi_enable() expects this to be zero initially. */ > > + cpu0_err = 0; > > return; > > } > > While at it I also removed the stray 'return;'. Doh, sorry about that. Thanks! Cheers, Don -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 6d0a891..0838685 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -522,6 +522,9 @@ static void watchdog_nmi_disable(unsigned int cpu) /* should be in cleanup, but blocks oprofile */ perf_event_release_kernel(event); } + if (cpu == 0) + /* watchdog_nmi_enable() expects this to be zero initially. */ + cpu0_err = 0; return; } #else