[V2 PATCH 0/3] x86: Fix panic vs. NMI issues

Hidehiro Kawai
2015-07-27T05:11:15Z

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