linux-kernel - [PATCH v2 2/3] x86/mce: Move message printing from mce_notify_irq to mce_early

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Message-ID: <20250210154707.114219-3-nik.borisov@suse.com>
Date: Mon, 10 Feb 2025 17:47:05 +0200
From: Nikolay Borisov <nik.borisov@...e.com>
To: linux-edac@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
	x86@...nel.org,
	tony.luck@...el.com,
	Nikolay Borisov <nik.borisov@...e.com>
Subject: [PATCH v2 2/3] x86/mce: Move message printing from mce_notify_irq to mce_early_notifier()

Informing the user that an MCE has been logged from mce_notify_irq() is
somewhat misleading because whether the MCE has been logged actually
depends on whether CONFIG_X86_MCELOG_LEGACY is turned on or not.

Furthermore it was reported that actually having a message triggered
when an MCE is generated can be helpful in certain scenarios. Improve
the situation by lifting the printing to the generic
mce_early_notifier() as it's executed always and is independent of any
compile-time option.

Link: https://lore.kernel.org/all/CY8PR11MB7134D97F82DC001AE009637889E32@CY8PR11MB7134.namprd11.prod.outlook.com/
Signed-off-by: Nikolay Borisov <nik.borisov@...e.com>
---
 arch/x86/kernel/cpu/mce/core.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 89625ff79c3b..d55b1903fde6 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -591,15 +591,8 @@ EXPORT_SYMBOL_GPL(mce_is_correctable);
  */
 static int mce_notify_irq(void)
 {
-	/* Not more than two messages every minute */
-	static DEFINE_RATELIMIT_STATE(ratelimit, 60*HZ, 2);
-
 	if (test_and_clear_bit(0, &mce_need_notify)) {
 		mce_work_trigger();
-
-		if (__ratelimit(&ratelimit))
-			pr_info(HW_ERR "Machine check events logged\n");
-
 		return 1;
 	}
 
@@ -609,6 +602,8 @@ static int mce_notify_irq(void)
 static int mce_early_notifier(struct notifier_block *nb, unsigned long val,
 			      void *data)
 {
+	/* Not more than two messages every minute */
+	static DEFINE_RATELIMIT_STATE(ratelimit, 60*HZ, 2);
 	struct mce_hw_err *err = to_mce_hw_err(data);
 
 	if (!err)
@@ -619,6 +614,9 @@ static int mce_early_notifier(struct notifier_block *nb, unsigned long val,
 
 	set_bit(0, &mce_need_notify);
 
+	if (__ratelimit(&ratelimit))
+		pr_info(HW_ERR "Machine check event detected\n");
+
 	mce_notify_irq();
 
 	return NOTIFY_DONE;
-- 
2.43.0