x86: Add sysctl to allow panic on IOCK NMI error (5211a242) · Commits · 戴 / test

This patch introduces a new sysctl: /proc/sys/kernel/panic_on_io_nmi which defaults to 0 (off). When enabled, the kernel panics when the kernel receives an NMI caused by an IO error. The IO error triggered NMI indicates a serious system condition, which could result in IO data corruption. Rather than contiuing, panicing and dumping might be a better choice, so one can figure out what's causing the IO error. This could be especially important to companies running IO intensive applications where corruption must be avoided, e.g. a bank's databases. [ SuSE has been shipping it for a while, it was done at the request of a large database vendor, for their users. ] Signed-off-by:

Kurt Garloff <garloff@suse.de> Signed-off-by:

Roberto Angelino <robertangelino@gmail.com> Signed-off-by:

Greg Kroah-Hartman <gregkh@suse.de> Cc: "Eric W. Biederman" <ebiederm@xmission.com> LKML-Reference: <20090624213211.GA11291@kroah.com> Signed-off-by:

Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/dumpstack.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -22,6 +22,7 @@
		#include "dumpstack.h"

		int panic_on_unrecovered_nmi;
		int panic_on_io_nmi;
		unsigned int code_bytes = 64;
		int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;
		static int die_counter;

arch/x86/kernel/traps.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -346,6 +346,9 @@ io_check_error(unsigned char reason, struct pt_regs *regs)
		printk(KERN_EMERG "NMI: IOCK error (debug interrupt?)\n");
		show_registers(regs);

		if (panic_on_io_nmi)
		panic("NMI IOCK error: Not continuing");

		/* Re-enable the IOCK line, wait for a few seconds */
		reason = (reason & 0xf) \| 8;
		outb(reason, 0x61);

include/linux/kernel.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -303,6 +303,7 @@ extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in
		extern int panic_timeout;
		extern int panic_on_oops;
		extern int panic_on_unrecovered_nmi;
		extern int panic_on_io_nmi;
		extern const char *print_tainted(void);
		extern void add_taint(unsigned flag);
		extern int test_taint(unsigned flag);

kernel/sysctl.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -743,6 +743,14 @@ static struct ctl_table kern_table[] = {
		.mode = 0644,
		.proc_handler = &proc_dointvec,
		},
		{
		.ctl_name = CTL_UNNUMBERED,
		.procname = "panic_on_io_nmi",
		.data = &panic_on_io_nmi,
		.maxlen = sizeof(int),
		.mode = 0644,
		.proc_handler = &proc_dointvec,
		},
		{
		.ctl_name = KERN_BOOTLOADER_TYPE,
		.procname = "bootloader_type",

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