When an HA cluster software or administrator detects non-response
of a host, they issue an NMI to the host to completely stop current
works and take a crash dump. If the kernel has already panicked
or is capturing a crash dump at that time, further NMI can cause
a crash dump failure.
To solve this issue, this patch set does two things:
- Don't panic on NMI if the kernel has already panicked
- Introduce "noextnmi" boot option which masks external NMI at the
boot time (supported only for x86)
V2:
- Use atomic_cmpxchg() instead of current spin_trylock() to exclude
concurrent accesses to panic() and crash_kexec()
- Don't introduce no-lock version of panic() and crash_kexec()
---
Hidehiro Kawai (3):
x86/panic: Fix re-entrance problem due to panic on NMI
kexec: Fix race between panic() and crash_kexec() called directly
x86/apic: Introduce noextnmi boot option
Documentation/kernel-parameters.txt | 4 ++++
arch/x86/kernel/apic/apic.c | 17 ++++++++++++++++-
arch/x86/kernel/nmi.c | 15 +++++++++++----
include/linux/kernel.h | 1 +
kernel/kexec.c | 20 ++++++++++++++++++++
kernel/panic.c | 13 ++++++++++---
6 files changed, 62 insertions(+), 8 deletions(-)
--
Hidehiro Kawai
Hitachi, Ltd. Research & Development Group
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