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

From: Disconnect (lkml@sigkill.net)
Date: Mon Jul 07 2003 - 11:01:42 EST

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

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 <lkml@sigkill.net>

# 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 --- a/arch/i386/kernel/process.c Mon Jul 7 11:42:50 2003 +++ b/arch/i386/kernel/process.c Mon Jul 7 11:42:50 2003 @@ -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;

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