Commit 04c6862c authored by Seiji Aguchi's avatar Seiji Aguchi Committed by Linus Torvalds
Browse files

kmsg_dump: add kmsg_dump() calls to the reboot, halt, poweroff and emergency_restart paths 



We need to know the reason why system rebooted in support service.
However, we can't inform our customers of the reason because final
messages are lost on current Linux kernel.

This patch improves the situation above because the final messages are
saved by adding kmsg_dump() to reboot, halt, poweroff and
emergency_restart path.

Signed-off-by: default avatarSeiji Aguchi <seiji.aguchi@hds.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Marco Stornelli <marco.stornelli@gmail.com>
Reviewed-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Reviewed-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent fc2d557c

include/linux/kmsg_dump.h

+4 −0
Original line number Diff line number Diff line
@@ -18,6 +18,10 @@ enum kmsg_dump_reason { 
	KMSG_DUMP_OOPS,

	KMSG_DUMP_PANIC,

	KMSG_DUMP_KEXEC,

	KMSG_DUMP_RESTART,

	KMSG_DUMP_HALT,

	KMSG_DUMP_POWEROFF,

	KMSG_DUMP_EMERG,

};



/**

kernel/printk.c

+4 −0
Original line number Diff line number Diff line
@@ -1539,6 +1539,10 @@ static const char * const kmsg_reasons[] = { 
	[KMSG_DUMP_OOPS]	= "oops",

	[KMSG_DUMP_PANIC]	= "panic",

	[KMSG_DUMP_KEXEC]	= "kexec",

	[KMSG_DUMP_RESTART]	= "restart",

	[KMSG_DUMP_HALT]	= "halt",

	[KMSG_DUMP_POWEROFF]	= "poweroff",

	[KMSG_DUMP_EMERG]	= "emergency_restart",

};



static const char *kmsg_to_str(enum kmsg_dump_reason reason)

kernel/sys.c

+6 −0
Original line number Diff line number Diff line
@@ -43,6 +43,8 @@ 
#include <linux/kprobes.h>

#include <linux/user_namespace.h>



#include <linux/kmsg_dump.h>



#include <asm/uaccess.h>

#include <asm/io.h>

#include <asm/unistd.h>
@@ -285,6 +287,7 @@ out_unlock: 
 */

void emergency_restart(void)

{

	kmsg_dump(KMSG_DUMP_EMERG);

	machine_emergency_restart();

}

EXPORT_SYMBOL_GPL(emergency_restart);
@@ -312,6 +315,7 @@ void kernel_restart(char *cmd) 
		printk(KERN_EMERG "Restarting system.\n");

	else

		printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);

	kmsg_dump(KMSG_DUMP_RESTART);

	machine_restart(cmd);

}

EXPORT_SYMBOL_GPL(kernel_restart);
@@ -333,6 +337,7 @@ void kernel_halt(void) 
	kernel_shutdown_prepare(SYSTEM_HALT);

	sysdev_shutdown();

	printk(KERN_EMERG "System halted.\n");

	kmsg_dump(KMSG_DUMP_HALT);

	machine_halt();

}
@@ -351,6 +356,7 @@ void kernel_power_off(void) 
	disable_nonboot_cpus();

	sysdev_shutdown();

	printk(KERN_EMERG "Power down.\n");

	kmsg_dump(KMSG_DUMP_POWEROFF);

	machine_power_off();

}

EXPORT_SYMBOL_GPL(kernel_power_off);

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