diff options
| author |   Thomas Gleixner <tglx@linutronix.de> | 2021-11-29 18:46:48 +0100 |
|---|---|---|
| committer |   Peter Zijlstra <peterz@infradead.org> | 2021-12-04 10:56:23 +0100 |
| commit | 0c1d7a2c2d32fac7ff4a644724b2d52a64184645 (patch) | |
| tree | 7d973e81c916d17c106e916ba9c3ec63cbf93865 | |
| parent | locking/rtmutex: Add rt_mutex_lock_nest_lock() and rt_mutex_lock_killable(). (diff) | |
| download | linux-dev-0c1d7a2c2d32fac7ff4a644724b2d52a64184645.tar.xz linux-dev-0c1d7a2c2d32fac7ff4a644724b2d52a64184645.zip | |
lockdep: Remove softirq accounting on PREEMPT_RT.
There is not really a softirq context on PREEMPT_RT. Softirqs on
PREEMPT_RT are always invoked within the context of a threaded
interrupt handler or within ksoftirqd. The "in-softirq" context is
preemptible and is protected by a per-CPU lock to ensure mutual
exclusion.
There is no difference on PREEMPT_RT between spin_lock_irq() and
spin_lock() because the former does not disable interrupts. Therefore
if a lock is used in_softirq() and locked once with spin_lock_irq()
then lockdep will report this with "inconsistent {SOFTIRQ-ON-W} ->
{IN-SOFTIRQ-W} usage".
Teach lockdep that we don't really do softirqs on -RT.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20211129174654.668506-6-bigeasy@linutronix.de
| -rw-r--r-- | include/linux/irqflags.h | 23 | ||||
| -rw-r--r-- | kernel/locking/lockdep.c | 2 |
2 files changed, 17 insertions, 8 deletions
diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h index 600c10da321a..4b140938b03e 100644 --- a/include/linux/irqflags.h +++ b/include/linux/irqflags.h @@ -71,14 +71,6 @@ do { \ do { \ __this_cpu_dec(hardirq_context); \ } while (0) -# define lockdep_softirq_enter() \ -do { \ - current->softirq_context++; \ -} while (0) -# define lockdep_softirq_exit() \ -do { \ - current->softirq_context--; \ -} while (0) # define lockdep_hrtimer_enter(__hrtimer) \ ({ \ @@ -140,6 +132,21 @@ do { \ # define lockdep_irq_work_exit(__work) do { } while (0) #endif +#if defined(CONFIG_TRACE_IRQFLAGS) && !defined(CONFIG_PREEMPT_RT) +# define lockdep_softirq_enter() \ +do { \ + current->softirq_context++; \ +} while (0) +# define lockdep_softirq_exit() \ +do { \ + current->softirq_context--; \ +} while (0) + +#else +# define lockdep_softirq_enter() do { } while (0) +# define lockdep_softirq_exit() do { } while (0) +#endif + #if defined(CONFIG_IRQSOFF_TRACER) || \ defined(CONFIG_PREEMPT_TRACER) extern void stop_critical_timings(void); diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 2270ec68f10a..4a882f83aeb9 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -5485,6 +5485,7 @@ static noinstr void check_flags(unsigned long flags) } } +#ifndef CONFIG_PREEMPT_RT /* * We dont accurately track softirq state in e.g. * hardirq contexts (such as on 4KSTACKS), so only @@ -5499,6 +5500,7 @@ static noinstr void check_flags(unsigned long flags) DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); } } +#endif if (!debug_locks) print_irqtrace_events(current); |