All of lore.kernel.org
 help / color / mirror / Atom feed
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


  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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210830172627.267989-5-bigeasy@linutronix.de \
    --to=bigeasy@linutronix.de \
    --cc=andreyknvl@gmail.com \
    --cc=dvyukov@google.com \
    --cc=elver@google.com \
    --cc=kasan-dev@googlegroups.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=rostedt@goodmis.org \
    --cc=tglx@linutronix.de \
    --cc=williams@redhat.com \
    --subject='Re: [PATCH 4/5] kcov: Avoid enable+disable interrupts if '\!'in_task().' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.