Commit-ID: 63a809a2dc53b91268dd915bbcbd425063893676
Gitweb: http://git.kernel.org/tip/63a809a2dc53b91268dd915bbcbd425063893676
Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
AuthorDate: Fri, 1 May 2009 12:23:17 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Fri, 1 May 2009 13:23:44 +0200
perf_counter: fix nmi-watchdog interaction
When we don't have any perf-counters active, don't act like we know
what the NMI is for.
[ Impact: fix hard hang with nmi_watchdog=2 ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Corey Ashford <cjashfor@xxxxxxxxxxxxxxxxxx>
LKML-Reference: <20090501102533.109867793@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
arch/x86/kernel/cpu/perf_counter.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c
index fc06f4d..d4c0cc9 100644
--- a/arch/x86/kernel/cpu/perf_counter.c
+++ b/arch/x86/kernel/cpu/perf_counter.c
@@ -871,6 +871,9 @@ perf_counter_nmi_handler(struct notifier_block *self,
struct pt_regs *regs;
int ret;
+ if (!atomic_read(&num_counters))
+ return NOTIFY_DONE;
+
switch (cmd) {
case DIE_NMI:
case DIE_NMI_IPI:
--
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