Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162606AbbKTKZW (ORCPT ); Fri, 20 Nov 2015 05:25:22 -0500 Received: from mailx.hitachi.co.jp ([133.145.228.49]:50396 "EHLO mailx.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752209AbbKTKZR (ORCPT ); Fri, 20 Nov 2015 05:25:17 -0500 X-AuditID: 85900ec0-9afc5b9000001a57-97-564eeaaa9fb8 X-Mailbox-Line: From nobody Fri Nov 20 18:36:44 2015 Subject: [V5 PATCH 0/4] Fix race issues among panic, NMI and crash_kexec To: Jonathan Corbet , Peter Zijlstra , Ingo Molnar , "Eric W. Biederman" , "H. Peter Anvin" , Andrew Morton , Thomas Gleixner , Vivek Goyal From: Hidehiro Kawai Cc: Baoquan He , linux-doc@vger.kernel.org, x86@kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, Michal Hocko , Borislav Petkov , Masami Hiramatsu Date: Fri, 20 Nov 2015 18:36:42 +0900 Message-ID: <20151120093641.4285.97253.stgit@softrs> User-Agent: StGit/0.16 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3266 Lines: 82 When an HA clustering software or administrator detects unresponsiveness 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. Also, crash_kexec() called from oops context and panic() can cause race conditions. To solve these issues, this patch set does following things: - Don't call panic() on NMI if the kernel has already panicked - Extend exclusion control currently done by panic_lock to crash_kexec - Introduce "apic_extnmi=none" boot option which masks external NMI NMI at the boot time Additionally, "apic_extnmi=all" is provieded. This option unmasks external NMI for all CPUs. This would help cause kernel panic even if CPU 0 can't handle an external NMI due to hang-up in NMI context or being handled by other NMI handlers. This patch set can be applied to current -tip tree. V5: - Use WRITE_ONCE() for crash_ipi_done to keep the instruction order (PATCH 2/4) - Address concurrent unknown/external NMI case, too (PATCH 2/4) - Fix build errors (PATCH 3/4) - Rename "noextnmi" boot option to "apic_extnmi" and expand its feature (PATCH 4/4) V4: https://lkml.org/lkml/2015/9/25/193 - Improve comments and descriptions (PATCH 1/4 to 3/4) - Use new __crash_kexec(), no exclusion check version of crash_kexec(), instead of checking if panic_cpu is the current cpu or not (PATCH 3/4) V3: https://lkml.org/lkml/2015/8/6/39 - Introduce nmi_panic() macro to reduce code duplication - In the case of panic on NMI, don't return from NMI handlers if another cpu already panicked V2: https://lkml.org/lkml/2015/7/27/31 - 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() V1: https://lkml.org/lkml/2015/7/22/81 --- Hidehiro Kawai (4): panic/x86: Fix re-entrance problem due to panic on NMI panic/x86: Allow cpus to save registers even if they are looping in NMI context kexec: Fix race between panic() and crash_kexec() called directly x86/apic: Introduce apic_extnmi boot option Documentation/kernel-parameters.txt | 9 +++++++++ arch/x86/include/asm/apic.h | 5 +++++ arch/x86/include/asm/reboot.h | 1 + arch/x86/kernel/apic/apic.c | 31 ++++++++++++++++++++++++++++++- arch/x86/kernel/nmi.c | 27 ++++++++++++++++++++++----- arch/x86/kernel/reboot.c | 28 ++++++++++++++++++++++++++++ include/linux/kernel.h | 21 +++++++++++++++++++++ include/linux/kexec.h | 2 ++ kernel/kexec_core.c | 26 +++++++++++++++++++++++++- kernel/panic.c | 29 ++++++++++++++++++++++++----- kernel/watchdog.c | 2 +- 11 files changed, 168 insertions(+), 13 deletions(-) -- Hidehiro Kawai Hitachi, Ltd. Research & Development Group -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/