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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2021-11-08 18:35:37 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-09 10:02:52 -0800
commit22036abe17c9f6e295bd9d767312cfb92fc9cf0a (patch)
tree416050aa9191810ecc570ab5bdfaf88e751f3918
parent741ddd4519c4d21eb7313e89a2c4ccc44a3dd6b9 (diff)
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 <bigeasy@linutronix.de> Acked-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Marco Elver <elver@google.com> Tested-by: Marco Elver <elver@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Cc: Clark Williams <williams@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/kcov.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/kcov.c b/kernel/kcov.c
index 4f910231d99a..620dc4ffeb68 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;