This is v5 post. Newly added patch 0002 includes the change related to KEXEC_JUMP path. Patch 0003 only includes the regression fix.
A regression bug was introduced in below commit. commit 522e66464467 ("x86/apic: Disable I/O APIC before shutdown of the local APIC") It caused the action to fail that we try to restore boot irq mode in reboot and kexec/kdump. Details can be seen in patch 0003. Warning can always be seen during kdump kernel boot on qemu/kvm platform. Our customer even saw casual kdump kernel hang once in ~30 attempts during stress testing of kdump on KVM machine. v4->v5: Take out the change related to KEXEC_JUMP to a new patch 0002 according to Eric's suggestion. Patch 0003 in this series only includes the regression fix. v3->v4: Eric pointed out that in patch 0002 the change related to KEXEC_JUMP is not right. Correct it. Add Fixes tag and Cc to stable. v2->v3: Change as Eric suggested: Rerrange patches and change code and messy function/variable naming. Change patch subject and log to make it more understandable. *** BLURB HERE *** Baoquan He (6): x86/apic: Split out restore_boot_irq_mode from disable_IO_APIC x86/apic: Replace disable_IO_APIC for KEXEC_JUMP x86/apic: Fix restoring boot irq mode in reboot and kexec/kdump x86/apic: Remove useless disable_IO_APIC x86/apic: Rename variable/function related to x86_io_apic_ops x86/apic: Set up through-local-APIC on boot CPU if 'noapic' specified arch/x86/include/asm/io_apic.h | 9 +++++---- arch/x86/include/asm/x86_init.h | 8 ++++---- arch/x86/kernel/apic/apic.c | 2 +- arch/x86/kernel/apic/io_apic.c | 16 ++++------------ arch/x86/kernel/crash.c | 3 ++- arch/x86/kernel/machine_kexec_32.c | 8 ++++---- arch/x86/kernel/machine_kexec_64.c | 8 ++++---- arch/x86/kernel/reboot.c | 3 ++- arch/x86/kernel/x86_init.c | 6 +++--- arch/x86/xen/apic.c | 2 +- drivers/iommu/irq_remapping.c | 4 ++-- 11 files changed, 32 insertions(+), 37 deletions(-) -- 2.13.6