centos-3.10-i686-fix-pcid-bug17925.patch 

https://bugs.centos.org/view.php?id=17925

When booting a recent 32-bit i686 kernel on a multi-cpu system with 'pcid' cpu feature, only the boot cpu is correctly initialized. The other cpu's fail to initialize, resulting in a badly running or crashing kernel.

The reason is two missing patches present in vanilla upstream kernels:

x86/mm: Disable PCID on 32-bit kernels

x86/mm/32: Move setup_clear_cpu_cap(X86_FEATURE_PCID) earlier

Submitted-by: Jerome Borsboom

Applied-by: Akemi Yagi <toracat@centos.org>

--- a/arch/x86/kernel/cpu/common.c	2020-10-21 10:17:08.000000000 -0700

+++ b/arch/x86/kernel/cpu/common.c	2020-12-09 22:10:47.945329193 -0800

@@ -1131,6 +1131,14 @@ static void __init early_identify_cpu(st

 		this_cpu->c_bsp_init(c);

 	cpu_set_bug_bits(c);

+

+#ifdef CONFIG_X86_32

+	/*

+	* Regardless of whether PCID is enumerated, the SDM says

+	* that it can't be enabled in 32-bit mode.

+	*/

+	setup_clear_cpu_cap(X86_FEATURE_PCID);

+#endif

 }

 void __init early_cpu_init(void)