Messages in this thread Patch in this message | | | Date | Mon, 18 Aug 2014 11:03:52 -0700 | From | tip-bot for Ulrich Obergfell <> | Subject | [tip:perf/watchdog] watchdog: Fix print-once on enable |
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Commit-ID: df577149594cefacd62740e86de080c6336d699e Gitweb: http://git.kernel.org/tip/df577149594cefacd62740e86de080c6336d699e Author: Ulrich Obergfell <uobergfe@redhat.com> AuthorDate: Mon, 11 Aug 2014 10:49:25 -0400 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Mon, 18 Aug 2014 11:17:46 +0200
watchdog: Fix print-once on enable
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> Cc: pbonzini@redhat.com Link: http://lkml.kernel.org/r/1407768567-171794-4-git-send-email-dzickus@redhat.com [ Applied small cleanups. ] Signed-off-by: Ingo Molnar <mingo@kernel.org> --- kernel/watchdog.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 4c2e11c..df5494e 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -506,7 +506,10 @@ static void watchdog_nmi_disable(unsigned int cpu) /* should be in cleanup, but blocks oprofile */ perf_event_release_kernel(event); } - return; + if (cpu == 0) { + /* watchdog_nmi_enable() expects this to be zero initially. */ + cpu0_err = 0; + } } #else static int watchdog_nmi_enable(unsigned int cpu) { return 0; }
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