From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> To: kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org Cc: Dmitry Vyukov <dvyukov@google.com>, Andrey Konovalov <andreyknvl@gmail.com>, Thomas Gleixner <tglx@linutronix.de>, Steven Rostedt <rostedt@goodmis.org>, Marco Elver <elver@google.com>, Clark Williams <williams@redhat.com>, Sebastian Andrzej Siewior <bigeasy@linutronix.de> Subject: [PATCH 4/5] kcov: Avoid enable+disable interrupts if !in_task(). Date: Mon, 30 Aug 2021 19:26:26 +0200 [thread overview] Message-ID: <20210830172627.267989-5-bigeasy@linutronix.de> (raw) In-Reply-To: <20210830172627.267989-1-bigeasy@linutronix.de> kcov_remote_start() may need to allocate memory in the in_task() case (otherwise per-CPU memory has been pre-allocated) and therefore requires enabled interrupts. The interrupts are enabled before checking if the allocation is required so if no allocation is required then the interrupts are needlessly enabled and disabled again. Enable interrupts only if memory allocation is performed. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- kernel/kcov.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/kcov.c b/kernel/kcov.c index 4f910231d99a2..620dc4ffeb685 100644 --- a/kernel/kcov.c +++ b/kernel/kcov.c @@ -869,19 +869,19 @@ void kcov_remote_start(u64 handle) size = CONFIG_KCOV_IRQ_AREA_SIZE; area = this_cpu_ptr(&kcov_percpu_data)->irq_area; } - spin_unlock_irqrestore(&kcov_remote_lock, flags); + spin_unlock(&kcov_remote_lock); /* Can only happen when in_task(). */ if (!area) { + local_irqrestore(flags); area = vmalloc(size * sizeof(unsigned long)); if (!area) { kcov_put(kcov); return; } + local_irq_save(flags); } - local_irq_save(flags); - /* Reset coverage size. */ *(u64 *)area = 0; -- 2.33.0
next prev parent reply other threads:[~2021-08-30 17:26 UTC|newest] Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-08-30 17:26 [PATCH 0/5] kcov: PREEMPT_RT fixup + misc Sebastian Andrzej Siewior 2021-08-30 17:26 ` [PATCH 1/5] Documentation/kcov: Include types.h in the example Sebastian Andrzej Siewior 2021-09-17 14:34 ` Dmitry Vyukov 2021-08-30 17:26 ` [PATCH 2/5] Documentation/kcov: Define `ip' " Sebastian Andrzej Siewior 2021-09-17 14:37 ` Dmitry Vyukov 2021-08-30 17:26 ` [PATCH 3/5] kcov: Allocate per-CPU memory on the relevant node Sebastian Andrzej Siewior 2021-09-17 14:38 ` Dmitry Vyukov 2021-08-30 17:26 ` Sebastian Andrzej Siewior [this message] 2021-09-17 14:50 ` [PATCH 4/5] kcov: Avoid enable+disable interrupts if !in_task() Dmitry Vyukov 2021-08-30 17:26 ` [PATCH 5/5] kcov: Replace local_irq_save() with a local_lock_t Sebastian Andrzej Siewior 2021-09-17 14:58 ` Dmitry Vyukov 2021-09-06 16:13 ` [PATCH 0/5] kcov: PREEMPT_RT fixup + misc Marco Elver 2021-09-06 16:28 ` Sebastian Andrzej Siewior 2021-09-20 9:26 ` Marco Elver 2021-09-20 9:50 ` Sebastian Andrzej Siewior
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