lockdep: Add posixtimer context tracing bits (d53f2b62) · Commits · 戴 / test

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

include/linux/irqflags.h

+12 −0

Original line number	Diff line number	Diff line
		@@ -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

kernel/time/posix-cpu-timers.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -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();
		}

		/*

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