linux-kernel - [RFC][PATCH v2 30/31] timers: x86/mce: Use __init

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Message-ID: <20221027150930.891623466@goodmis.org>
Date:   Thu, 27 Oct 2022 11:05:55 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     linux-kernel@...r.kernel.org
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Stephen Boyd <sboyd@...nel.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Tony Luck <tony.luck@...el.com>,
        Borislav Petkov <bp@...en8.de>, Ingo Molnar <mingo@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        "H. Peter Anvin" <hpa@...or.com>, linux-edac@...r.kernel.org
Subject: [RFC][PATCH v2 30/31] timers: x86/mce: Use __init_timer() for resetting timers

From: "Steven Rostedt (Google)" <rostedt@...dmis.org>

DEBUG_OBJECTS_TIMERS is now checking if a timer is ever enqueued, and if
so, it must call del_timer_shutdown() before freeing, otherwise
debug objects will trigger. This requires that once a timer is initialized
(and initialized for debug objects) it must not be re-initialized using
timer_setup(), as that will call the debug objects initialization code
again and trigger a bug if it was ever used.

As the mce reinitializes its timers on CPU hotplug, it must use
__init_timer() instead of timer_setup(), which will only initialize the
debug objects once.

Link: https://lore.kernel.org/all/20220407161745.7d6754b3@gandalf.local.home/

Cc: Tony Luck <tony.luck@...el.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: x86@...nel.org
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: linux-edac@...r.kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>
---
 arch/x86/kernel/cpu/mce/core.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 2c8ec5c71712..d2653c7d40b3 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -2051,14 +2051,24 @@ static void __mcheck_cpu_setup_timer(void)
 {
 	struct timer_list *t = this_cpu_ptr(&mce_timer);
 
-	timer_setup(t, mce_timer_fn, TIMER_PINNED);
+	/*
+	 * timer_setup() may only be used on a timer for the
+	 * first time it is initialized. This resets the
+	 * timer on CPU hotplug, so use __init_timer() instead.
+	 */
+	__init_timer(t, mce_timer_fn, TIMER_PINNED);
 }
 
 static void __mcheck_cpu_init_timer(void)
 {
 	struct timer_list *t = this_cpu_ptr(&mce_timer);
 
-	timer_setup(t, mce_timer_fn, TIMER_PINNED);
+	/*
+	 * timer_setup() may only be used on a timer for the
+	 * first time it is initialized. This resets the
+	 * timer on CPU hotplug, so use __init_timer() instead.
+	 */
+	__init_timer(t, mce_timer_fn, TIMER_PINNED);
 	mce_start_timer(t);
 }
 
-- 
2.35.1