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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2015-04-10 11:50:22 +0200
committerSteven Rostedt <rostedt@goodmis.org>2015-11-12 12:21:40 -0500
commit325310675870f9999a611245057029b254435c11 (patch)
tree6ee7566d133896a314aaf36a9efa99297d758afb
parentfc226afda31cc5879f78f6fce3a8c1c5df286858 (diff)
downloadlinux-rt-325310675870f9999a611245057029b254435c11.tar.gz
kernel/irq_work: fix no_hz deadlock
Invoking NO_HZ's irq_work callback from timer irq is not working very well if the callback decides to invoke hrtimer_cancel(): |hrtimer_try_to_cancel+0x55/0x5f |hrtimer_cancel+0x16/0x28 |tick_nohz_restart+0x17/0x72 |__tick_nohz_full_check+0x8e/0x93 |nohz_full_kick_work_func+0xe/0x10 |irq_work_run_list+0x39/0x57 |irq_work_tick+0x60/0x67 |update_process_times+0x57/0x67 |tick_sched_handle+0x4a/0x59 |tick_sched_timer+0x3b/0x64 |__run_hrtimer+0x7a/0x149 |hrtimer_interrupt+0x1cc/0x2c5 and here we deadlock while waiting for the lock which we are holding. To fix this I'm doing the same thing that upstream is doing: is the irq_work dedicated IRQ and use it only for what is marked as "hirq" which should only be the FULL_NO_HZ related work. Cc: stable-rt@vger.kernel.org Reported-by: Carsten Emde <C.Emde@osadl.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> [ Added check for in_irq() before calling irq_work_run() ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
-rw-r--r--arch/powerpc/kernel/time.c2
-rw-r--r--arch/sparc/kernel/pcr.c2
-rw-r--r--arch/x86/kernel/irq_work.c2
-rw-r--r--kernel/irq_work.c5
-rw-r--r--kernel/time/tick-sched.c5
-rw-r--r--kernel/timer.c2
6 files changed, 8 insertions, 10 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index fe66ccabb744..03c314694e58 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -423,7 +423,7 @@ unsigned long profile_pc(struct pt_regs *regs)
EXPORT_SYMBOL(profile_pc);
#endif
-#if defined(CONFIG_IRQ_WORK) && !defined(CONFIG_PREEMPT_RT_FULL)
+#if defined(CONFIG_IRQ_WORK)
/*
* 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable...
diff --git a/arch/sparc/kernel/pcr.c b/arch/sparc/kernel/pcr.c
index dbb51a6441a6..269af58497aa 100644
--- a/arch/sparc/kernel/pcr.c
+++ b/arch/sparc/kernel/pcr.c
@@ -43,12 +43,10 @@ void __irq_entry deferred_pcr_work_irq(int irq, struct pt_regs *regs)
set_irq_regs(old_regs);
}
-#ifndef CONFIG_PREEMPT_RT_FULL
void arch_irq_work_raise(void)
{
set_softint(1 << PIL_DEFERRED_PCR_WORK);
}
-#endif
const struct pcr_ops *pcr_ops;
EXPORT_SYMBOL_GPL(pcr_ops);
diff --git a/arch/x86/kernel/irq_work.c b/arch/x86/kernel/irq_work.c
index 129b8bb73de2..ca8f703a1e70 100644
--- a/arch/x86/kernel/irq_work.c
+++ b/arch/x86/kernel/irq_work.c
@@ -18,7 +18,6 @@ void smp_irq_work_interrupt(struct pt_regs *regs)
irq_exit();
}
-#ifndef CONFIG_PREEMPT_RT_FULL
void arch_irq_work_raise(void)
{
#ifdef CONFIG_X86_LOCAL_APIC
@@ -29,4 +28,3 @@ void arch_irq_work_raise(void)
apic_wait_icr_idle();
#endif
}
-#endif
diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index 35d21f93bbe8..5f7d93d89c7f 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -16,6 +16,7 @@
#include <linux/tick.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
+#include <linux/interrupt.h>
#include <asm/processor.h>
@@ -51,11 +52,7 @@ static bool irq_work_claim(struct irq_work *work)
return true;
}
-#ifdef CONFIG_PREEMPT_RT_FULL
-void arch_irq_work_raise(void)
-#else
void __weak arch_irq_work_raise(void)
-#endif
{
/*
* Lame architectures will get the timer tick callback
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index aedf4c21e2c1..b280dba280b3 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -174,6 +174,11 @@ static bool can_stop_full_tick(void)
return false;
}
+ if (!arch_irq_work_has_interrupt()) {
+ trace_tick_stop(0, "missing irq work interrupt\n");
+ return false;
+ }
+
/* sched_clock_tick() needs us? */
#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
/*
diff --git a/kernel/timer.c b/kernel/timer.c
index a2bfef4a8f23..4254253f2267 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1450,7 +1450,7 @@ void update_process_times(int user_tick)
scheduler_tick();
run_local_timers();
rcu_check_callbacks(cpu, user_tick);
-#if defined(CONFIG_IRQ_WORK)
+#if defined(CONFIG_IRQ_WORK) && !defined(CONFIG_PREEMPT_RT_FULL)
if (in_irq())
irq_work_run();
#endif