diff options
authorLinus Walleij <>2012-04-10 12:37:42 +0100
committerRussell King <>2012-04-15 22:00:29 +0100
commit9f85550347f51c79a917b2aec04c90691c11e20a (patch)
parent6b8e5c912f4294611351aba151324764ebbefa1b (diff)
ARM: 7359/2: smp_twd: Only wait for reprogramming on active cpus
During booting of cpu1, there is a short window where cpu1 is online, but not active where cpu1 is occupied by waiting to become active. If cpu0 then decides to schedule something on cpu1 and wait for it to complete, before cpu0 has set cpu1 active, we have a deadlock. Typically it's this CPU frequency transition that happens at this time, so let's just not wait for it to happen, it will happen whenever the CPU eventually comes online instead. Cc: Peter Zijlstra <> Cc: Signed-off-by: Jonas Aaberg <> Reviewed-by: Rickard Andersson <> Signed-off-by: Linus Walleij <> Signed-off-by: Russell King <>
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c
index fef42b21cecb..5b150afb995b 100644
--- a/arch/arm/kernel/smp_twd.c
+++ b/arch/arm/kernel/smp_twd.c
@@ -118,10 +118,14 @@ static int twd_cpufreq_transition(struct notifier_block *nb,
* The twd clock events must be reprogrammed to account for the new
* frequency. The timer is local to a cpu, so cross-call to the
* changing cpu.
+ *
+ * Only wait for it to finish, if the cpu is active to avoid
+ * deadlock when cpu1 is spinning on while(!cpu_active(cpu1)) during
+ * booting of that cpu.
smp_call_function_single(freqs->cpu, twd_update_frequency,
- NULL, 1);
+ NULL, cpu_active(freqs->cpu));
return NOTIFY_OK;