[2.4][TRIVIAL] Use of uninitialized vars in arch/i386/kernel/process.c

Sorry for the longish To list, not sure who's responsible for this particular piece. (And if I got it wrong even after all that, please let me know..)

This is for 2.4; in 2.5 reboot.c has identical code with an identical problem. (I'll send a separate patch after getting feedback on this one.)

If you don't pass reboot=, reboot_mode and reboot_thru_bios are used uninitialized and (in the case of reboot_mode) written directly to memory for the bios.

This patch sets reboot_mode to 0x1234 by default, and reboot_thru_bios (used in "if(!reboot_thru_bios)") to 1.

void machine_restart(char * __unused)
{
..[smp shutdown]..

  if(!reboot_thru_bios) {
        /* rebooting needs to touch the page at absolute addr 0 */
        *((unsigned short *)__va(0x472)) = reboot_mode;
...
        machine_real_restart(jump_to_bios, sizeof(jump_to_bios));
}

void machine_real_restart(unsigned char *code, int length) {
.....
/* Write 0x1234 to absolute memory location 0x472. The BIOS reads
this on booting to tell it to "Bypass memory test (also warm boot)". This seems like a fairly standard thing that gets set by REBOOT.COM programs, and the previous reset routine did this too. */

*((unsigned short *)0x472) = reboot_mode;
...
}

Disconnect <[email protected]>

# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
# ChangeSet 1.1042 -> 1.1043
# arch/i386/kernel/process.c 1.14 -> 1.15
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 03/07/07 dis@slappy.(none) 1.1043
# Initialize reboot_mode to defaults (according to comments) even if reboot= is lacking. Ditto for reboot_thru_bios. # (Warm boot, use bios.)
# --------------------------------------------
#

diff -Nru a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
@@ -152,8 +152,8 @@
 __setup("idle=", idle_setup);
 
 static long no_idt[2];
-static int reboot_mode;
-int reboot_thru_bios;
+static int reboot_mode=0x1234;
+int reboot_thru_bios=1;
 
 #ifdef CONFIG_SMP
 int reboot_smp = 0;

reboot_mode is static so defaults to zero.