[PATCH 6.12.y 3/3] x86/mce: Set up the polling timer before CMCI discovery

[Sasha Levin <sashal@kernel.org>]

From: Breno Leitao <leitao@debian.org>

[ Upstream commit a213dfaa2596c1c0dc4dae91c14fbfa499c03223 ]

I hit the following on one of my machines:

  mce: CPU0 BANK15 CMCI inherited storm
  ------------[ cut here ]------------
  ODEBUG: assert_init not available (active state 0) object: (____ptrval____) object type: timer_list hint: 0x0
  WARNING: lib/debugobjects.c:632 at debug_object_assert_init+0x178/0x230, CPU#0: swapper/0/0
  CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 7.2.0-rc5 #3 PREEMPTLAZY
  RIP: 0010:debug_object_assert_init+0x18f/0x230
  Call Trace:
   <TASK>
   __mod_timer
   mce_timer_kick
   cmci_discover
   intel_init_cmci
   mce_intel_feature_init
   mcheck_cpu_init
   identify_cpu
   identify_boot_cpu
   arch_cpu_finalize_init
   start_kernel

A second splat follows right after, from timer_setup() finding that same
timer already queued:

  ODEBUG: init active (active state 0) object: (____ptrval____) object type: timer_list hint: stub_timer+0x0/0x10

This is happening because CMCI storm detection is trying to modify the timer
before latter was properly set up.

Set up the timer first. __mcheck_cpu_setup_timer() only calls timer_setup(),
and depends on neither the generic nor the vendor init.

  [ bp: Massage commit message. ]

Fixes: 1f68ce2a0272 ("x86/mce: Handle Intel threshold interrupt storms")
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260803-mce_timer_init-v1-1-9539db424330@debian.org
[ kept 6.12's `__mcheck_cpu_init_clear_banks()`/`__mcheck_cpu_check_banks()` pair instead of the merged `__mcheck_cpu_init_prepare_banks()` ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kernel/cpu/mce/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index c95698dd648ac..01a17e729a80f 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -2251,11 +2251,11 @@ void mcheck_cpu_init(struct cpuinfo_x86 *c)
 
 	mca_cfg.initialized = 1;
 
+	__mcheck_cpu_setup_timer();
 	__mcheck_cpu_init_generic();
 	__mcheck_cpu_init_vendor(c);
 	__mcheck_cpu_init_clear_banks();
 	__mcheck_cpu_check_banks();
-	__mcheck_cpu_setup_timer();
 	cr4_set_bits(X86_CR4_MCE);
 }
 
-- 
2.53.0