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Date: Thu, 02 Dec 2010 00:16:58 -0800
From: Yinghai Lu <yinghai@...nel.org>
To: Don Zickus <dzickus@...hat.com>
CC: Ingo Molnar <mingo@...e.hu>, fweisbec@...il.com,
gorcunov@...nvz.org, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] x86, NMI: add back unknown_nmi_panic and nmi_watchdog
sysctls
On 11/29/2010 02:07 PM, Don Zickus wrote:
> Originally adapted from Huang Ying's patch which moved the unknown_nmi_panic
> to the traps.c file. Because the old nmi watchdog was deleted before this
> change happened, the unknown_nmi_panic sysctl was lost. This re-adds it.
>
> Also, the nmi_watchdog sysctl was re-implemented and its documentation
> updated accordingly.
>
> Patch-inspired-by: Huang Ying <ying.huang@...el.com>
> Signed-off-by: Don Zickus <dzickus@...hat.com>
> ---
> Documentation/kernel-parameters.txt | 10 +---------
> arch/x86/kernel/apic/hw_nmi.c | 3 ---
> arch/x86/kernel/traps.c | 16 +++++++++++-----
> kernel/sysctl.c | 16 ++++++++++++++++
> kernel/sysctl_binary.c | 1 -
> kernel/watchdog.c | 2 ++
> 6 files changed, 30 insertions(+), 18 deletions(-)
>
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index cdd2a6e..5e55e46 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -1579,20 +1579,12 @@ and is between 256 and 4096 characters. It is defined in the file
>
> nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
> Format: [panic,][num]
> - Valid num: 0,1,2
> + Valid num: 0
> 0 - turn nmi_watchdog off
> - 1 - use the IO-APIC timer for the NMI watchdog
> - 2 - use the local APIC for the NMI watchdog using
> - a performance counter. Note: This will use one
> - performance counter and the local APIC's performance
> - vector.
> When panic is specified, panic when an NMI watchdog
> timeout occurs.
> This is useful when you use a panic=... timeout and
> need the box quickly up again.
> - Instead of 1 and 2 it is possible to use the following
> - symbolic names: lapic and ioapic
> - Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
>
> netpoll.carrier_timeout=
> [NET] Specifies amount of time (in seconds) that
> diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c
> index d13081e..a86840c 100644
> --- a/arch/x86/kernel/apic/hw_nmi.c
> +++ b/arch/x86/kernel/apic/hw_nmi.c
> @@ -100,6 +100,3 @@ static int __init register_trigger_all_cpu_backtrace(void)
> }
> early_initcall(register_trigger_all_cpu_backtrace);
> #endif
> -
> -/* STUB calls to mimic old nmi_watchdog behaviour */
> -int unknown_nmi_panic;
> diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
> index f02c179..bb6f041 100644
> --- a/arch/x86/kernel/traps.c
> +++ b/arch/x86/kernel/traps.c
> @@ -83,6 +83,8 @@ EXPORT_SYMBOL_GPL(used_vectors);
>
> static int ignore_nmis;
>
> +int unknown_nmi_panic;
> +
> static inline void conditional_sti(struct pt_regs *regs)
> {
> if (regs->flags & X86_EFLAGS_IF)
> @@ -300,6 +302,13 @@ gp_in_kernel:
> die("general protection fault", regs, error_code);
> }
>
> +static int __init setup_unknown_nmi_panic(char *str)
> +{
> + unknown_nmi_panic = 1;
> + return 1;
> +}
> +__setup("unknown_nmi_panic", setup_unknown_nmi_panic);
> +
> static notrace __kprobes void
> mem_parity_error(unsigned char reason, struct pt_regs *regs)
> {
> @@ -371,7 +380,7 @@ unknown_nmi_error(unsigned char reason, struct pt_regs *regs)
> reason, smp_processor_id());
>
> printk(KERN_EMERG "Do you have a strange power saving mode enabled?\n");
> - if (panic_on_unrecovered_nmi)
> + if (unknown_nmi_panic || panic_on_unrecovered_nmi)
> panic("NMI: Not continuing");
>
> printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
> @@ -397,11 +406,8 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
> if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
> == NOTIFY_STOP)
> return;
> -
> - unknown_nmi_error(reason, regs);
> -#else
> - unknown_nmi_error(reason, regs);
> #endif
> + unknown_nmi_error(reason, regs);
>
> return;
> }
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index d91b07d..140344d 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -733,6 +733,22 @@ static struct ctl_table kern_table[] = {
> .extra1 = &zero,
> .extra2 = &one,
> },
> + {
> + .procname = "nmi_watchdog",
> + .data = &watchdog_enabled,
> + .maxlen = sizeof (int),
> + .mode = 0644,
> + .proc_handler = proc_dowatchdog_enabled,
> + },
> +#endif
> +#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
> + {
> + .procname = "unknown_nmi_panic",
> + .data = &unknown_nmi_panic,
> + .maxlen = sizeof (int),
> + .mode = 0644,
> + .proc_handler = proc_dointvec,
> + },
> #endif
> #if defined(CONFIG_X86)
> {
> diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c
> index 1357c57..4b2545a 100644
> --- a/kernel/sysctl_binary.c
> +++ b/kernel/sysctl_binary.c
> @@ -136,7 +136,6 @@ static const struct bin_table bin_kern_table[] = {
> { CTL_INT, KERN_IA64_UNALIGNED, "ignore-unaligned-usertrap" },
> { CTL_INT, KERN_COMPAT_LOG, "compat-log" },
> { CTL_INT, KERN_MAX_LOCK_DEPTH, "max_lock_depth" },
> - { CTL_INT, KERN_NMI_WATCHDOG, "nmi_watchdog" },
> { CTL_INT, KERN_PANIC_ON_NMI, "panic_on_unrecovered_nmi" },
> {}
> };
> diff --git a/kernel/watchdog.c b/kernel/watchdog.c
> index fd77b69..e0f44dc 100644
> --- a/kernel/watchdog.c
> +++ b/kernel/watchdog.c
> @@ -57,6 +57,8 @@ static int __init hardlockup_panic_setup(char *str)
> {
> if (!strncmp(str, "panic", 5))
> hardlockup_panic = 1;
> + else if (!strncmp(str, "0", 1))
> + no_watchdog = 1;
> return 1;
> }
> __setup("nmi_watchdog=", hardlockup_panic_setup);
Thanks, unknown_nmi_panic works again.
Acked-by: Yinghai Lu <yinghai@...nel.org>
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