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authorThomas Gleixner <tglx@linutronix.de>2017-12-27 21:37:25 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-01-02 20:31:15 +0100
commit6fae6de72ad44e98b5ae58a662d110c58594aad9 (patch)
tree286abe65f8f53333655523cffd0fc6e0f3a2fb23 /include/linux
parent8f1aa64ab08621cc3d2b1600ab80da5d3128abb6 (diff)
timers: Reinitialize per cpu bases on hotplug
commit 26456f87aca7157c057de65c9414b37f1ab881d1 upstream. The timer wheel bases are not (re)initialized on CPU hotplug. That leaves them with a potentially stale clk and next_expiry valuem, which can cause trouble then the CPU is plugged. Add a prepare callback which forwards the clock, sets next_expiry to far in the future and reset the control flags to a known state. Set base->must_forward_clk so the first timer which is queued will try to forward the clock to current jiffies. Fixes: 500462a9de65 ("timers: Switch to a non-cascading wheel") Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Anna-Maria Gleixner <anna-maria@linutronix.de> Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1712272152200.2431@nanos Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/cpuhotplug.h2
-rw-r--r--include/linux/timer.h4
2 files changed, 4 insertions, 2 deletions
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 2477a5cb5bd5..fb83dee528a1 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -86,7 +86,7 @@ enum cpuhp_state {
CPUHP_MM_ZSWP_POOL_PREPARE,
CPUHP_KVM_PPC_BOOK3S_PREPARE,
CPUHP_ZCOMP_PREPARE,
- CPUHP_TIMERS_DEAD,
+ CPUHP_TIMERS_PREPARE,
CPUHP_MIPS_SOC_PREPARE,
CPUHP_BP_PREPARE_DYN,
CPUHP_BP_PREPARE_DYN_END = CPUHP_BP_PREPARE_DYN + 20,
diff --git a/include/linux/timer.h b/include/linux/timer.h
index ac66f29c6916..e0ea1fe87572 100644
--- a/include/linux/timer.h
+++ b/include/linux/timer.h
@@ -246,9 +246,11 @@ unsigned long round_jiffies_up(unsigned long j);
unsigned long round_jiffies_up_relative(unsigned long j);
#ifdef CONFIG_HOTPLUG_CPU
+int timers_prepare_cpu(unsigned int cpu);
int timers_dead_cpu(unsigned int cpu);
#else
-#define timers_dead_cpu NULL
+#define timers_prepare_cpu NULL
+#define timers_dead_cpu NULL
#endif
#endif