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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2020-03-21 12:26:04 +0100
committerPeter Zijlstra <peterz@infradead.org>2020-03-21 16:00:25 +0100
commitd53f2b62fcb63f6547c10d8c62bca19e957b0eef (patch)
treebd600c130fb6c4a189c81c2dbfb7bb70724f6296
parent49915ac35ca7b07c54295a72d905be5064afb89e (diff)
downloadlinux-d53f2b62fcb63f6547c10d8c62bca19e957b0eef.tar.bz2
lockdep: Add posixtimer context tracing bits
Splitting run_posix_cpu_timers() into two parts is work in progress which is stuck on other entry code related problems. The heavy lifting which involves locking of sighand lock will be moved into task context so the necessary execution time is burdened on the task and not on interrupt context. Until this work completes lockdep with the spinlock nesting rules enabled would emit warnings for this known context. Prevent it by setting "->irq_config = 1" for the invocation of run_posix_cpu_timers() so lockdep does not complain when sighand lock is acquried. This will be removed once the split is completed. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200321113242.751182723@linutronix.de
-rw-r--r--include/linux/irqflags.h12
-rw-r--r--kernel/time/posix-cpu-timers.c6
2 files changed, 17 insertions, 1 deletions
diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h
index f23f540e0ebb..a16adbb58f66 100644
--- a/include/linux/irqflags.h
+++ b/include/linux/irqflags.h
@@ -69,6 +69,16 @@ do { \
current->irq_config = 0; \
} while (0)
+# define lockdep_posixtimer_enter() \
+ do { \
+ current->irq_config = 1; \
+ } while (0)
+
+# define lockdep_posixtimer_exit() \
+ do { \
+ current->irq_config = 0; \
+ } while (0)
+
# define lockdep_irq_work_enter(__work) \
do { \
if (!(atomic_read(&__work->flags) & IRQ_WORK_HARD_IRQ))\
@@ -94,6 +104,8 @@ do { \
# define lockdep_softirq_exit() do { } while (0)
# define lockdep_hrtimer_enter(__hrtimer) do { } while (0)
# define lockdep_hrtimer_exit(__hrtimer) do { } while (0)
+# define lockdep_posixtimer_enter() do { } while (0)
+# define lockdep_posixtimer_exit() do { } while (0)
# define lockdep_irq_work_enter(__work) do { } while (0)
# define lockdep_irq_work_exit(__work) do { } while (0)
#endif
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 8ff6da77a01f..2c48a7233b19 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -1126,8 +1126,11 @@ void run_posix_cpu_timers(void)
if (!fastpath_timer_check(tsk))
return;
- if (!lock_task_sighand(tsk, &flags))
+ lockdep_posixtimer_enter();
+ if (!lock_task_sighand(tsk, &flags)) {
+ lockdep_posixtimer_exit();
return;
+ }
/*
* Here we take off tsk->signal->cpu_timers[N] and
* tsk->cpu_timers[N] all the timers that are firing, and
@@ -1169,6 +1172,7 @@ void run_posix_cpu_timers(void)
cpu_timer_fire(timer);
spin_unlock(&timer->it_lock);
}
+ lockdep_posixtimer_exit();
}
/*