From aede36fcefdc7ec2afbdb22411a563affe104a91 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Mon, 8 Nov 2021 18:35:37 -0800 Subject: [PATCH] kcov: avoid enable+disable interrupts if !in_task() 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. Link: https://lkml.kernel.org/r/20210923164741.1859522-5-bigeasy@linutronix.de Link: https://lore.kernel.org/r/20210830172627.267989-5-bigeasy@linutronix.de Signed-off-by: Sebastian Andrzej Siewior Acked-by: Dmitry Vyukov Acked-by: Marco Elver Tested-by: Marco Elver Reviewed-by: Andrey Konovalov Cc: Clark Williams Cc: Steven Rostedt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- 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; -- 2.39.5