[RFC][PATCH v2 30/31] timers: x86/mce: Use __init_timer() for resetting timers

[Steven Rostedt]

From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>

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@xxxxxxxxxxxxxxxxxx/

Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: linux-edac@xxxxxxxxxxxxxxx
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
 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