CVE-2026-80727x86/mce: Set up the polling timer before CMCI discovery

Official description

In the Linux kernel, the following vulnerability has been resolved: x86/mce: Set up the polling timer before CMCI discovery 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. ]

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/17ab68d0cf6a41bff61b1e13c6141d9e463736ae
• https://git.kernel.org/stable/c/e708fc1566ebd4a2d3f2546e6310d64d362db80d
• https://git.kernel.org/stable/c/4f4cba3947d2f0eceb32727e198ca2c149a653a9
• https://git.kernel.org/stable/c/a213dfaa2596c1c0dc4dae91c14fbfa499c03223