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[PATCH] x86_64: Disallow kprobes on NMI handlers 

A kprobe executes IRET early and that could cause NMI recursion
and stack corruption.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Andi Kleen 2006-02-03 21:50:41 +01:00 committed by Linus Torvalds
parent 2f01942536
commit eddb6fb9a5
3 changed files with 18 additions and 13 deletions
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3
arch/x86_64/kernel/entry.S
View File

@ -922,7 +922,7 @@ KPROBE_ENTRY(debug)
.previous .text
/* runs on exception stack */
ENTRY(nmi)
KPROBE_ENTRY(nmi)
INTR_FRAME
pushq $-1
CFI_ADJUST_CFA_OFFSET 8
@ -969,6 +969,7 @@ paranoid_schedule:
cli
jmp paranoid_userspace
CFI_ENDPROC
.previous .text
KPROBE_ENTRY(int3)
INTR_FRAME

7
arch/x86_64/kernel/nmi.c
View File

@ -24,6 +24,7 @@
#include <linux/sysdev.h>
#include <linux/nmi.h>
#include <linux/sysctl.h>
#include <linux/kprobes.h>
#include <asm/smp.h>
#include <asm/mtrr.h>
@ -468,7 +469,7 @@ void touch_nmi_watchdog (void)
touch_softlockup_watchdog();
}
void nmi_watchdog_tick (struct pt_regs * regs, unsigned reason)
void __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason)
{
int sum;
int touched = 0;
@ -512,14 +513,14 @@ void nmi_watchdog_tick (struct pt_regs * regs, unsigned reason)
}
}
static int dummy_nmi_callback(struct pt_regs * regs, int cpu)
static __kprobes int dummy_nmi_callback(struct pt_regs * regs, int cpu)
{
return 0;
}
static nmi_callback_t nmi_callback = dummy_nmi_callback;
asmlinkage void do_nmi(struct pt_regs * regs, long error_code)
asmlinkage __kprobes void do_nmi(struct pt_regs * regs, long error_code)
{
int cpu = safe_smp_processor_id();

21
arch/x86_64/kernel/traps.c
View File

@ -372,7 +372,7 @@ void out_of_line_bug(void)
static DEFINE_SPINLOCK(die_lock);
static int die_owner = -1;
unsigned long oops_begin(void)
unsigned __kprobes long oops_begin(void)
{
int cpu = safe_smp_processor_id();
unsigned long flags;
@ -391,7 +391,7 @@ unsigned long oops_begin(void)
return flags;
}
void oops_end(unsigned long flags)
void __kprobes oops_end(unsigned long flags)
{
die_owner = -1;
bust_spinlocks(0);
@ -400,7 +400,7 @@ void oops_end(unsigned long flags)
panic("Oops");
}
void __die(const char * str, struct pt_regs * regs, long err)
void __kprobes __die(const char * str, struct pt_regs * regs, long err)
{
static int die_counter;
printk(KERN_EMERG "%s: %04lx [%u] ", str, err & 0xffff,++die_counter);
@ -432,7 +432,7 @@ void die(const char * str, struct pt_regs * regs, long err)
do_exit(SIGSEGV);
}
void die_nmi(char *str, struct pt_regs *regs)
void __kprobes die_nmi(char *str, struct pt_regs *regs)
{
unsigned long flags = oops_begin();
@ -575,7 +575,8 @@ asmlinkage void __kprobes do_general_protection(struct pt_regs * regs,
}
}
static void mem_parity_error(unsigned char reason, struct pt_regs * regs)
static __kprobes void
mem_parity_error(unsigned char reason, struct pt_regs * regs)
{
printk("Uhhuh. NMI received. Dazed and confused, but trying to continue\n");
printk("You probably have a hardware problem with your RAM chips\n");
@ -585,7 +586,8 @@ static void mem_parity_error(unsigned char reason, struct pt_regs * regs)
outb(reason, 0x61);
}
static void io_check_error(unsigned char reason, struct pt_regs * regs)
static __kprobes void
io_check_error(unsigned char reason, struct pt_regs * regs)
{
printk("NMI: IOCK error (debug interrupt?)\n");
show_registers(regs);
@ -598,7 +600,8 @@ static void io_check_error(unsigned char reason, struct pt_regs * regs)
outb(reason, 0x61);
}
static void unknown_nmi_error(unsigned char reason, struct pt_regs * regs)
static __kprobes void
unknown_nmi_error(unsigned char reason, struct pt_regs * regs)
{ printk("Uhhuh. NMI received for unknown reason %02x.\n", reason);
printk("Dazed and confused, but trying to continue\n");
printk("Do you have a strange power saving mode enabled?\n");
@ -606,7 +609,7 @@ static void unknown_nmi_error(unsigned char reason, struct pt_regs * regs)
/* Runs on IST stack. This code must keep interrupts off all the time.
Nested NMIs are prevented by the CPU. */
asmlinkage void default_do_nmi(struct pt_regs *regs)
asmlinkage __kprobes void default_do_nmi(struct pt_regs *regs)
{
unsigned char reason = 0;
int cpu;
@ -658,7 +661,7 @@ asmlinkage void __kprobes do_int3(struct pt_regs * regs, long error_code)
/* Help handler running on IST stack to switch back to user stack
for scheduling or signal handling. The actual stack switch is done in
entry.S */
asmlinkage struct pt_regs *sync_regs(struct pt_regs *eregs)
asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs)
{
struct pt_regs *regs = eregs;
/* Did already sync */