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Commit 29b6cd79 authored Dec 18, 2007 by Masami Hiramatsu Committed by Ingo Molnar Dec 18, 2007

x86: jprobe bugfix



jprobe for x86-64 may cause kernel page fault when the jprobe_return()
is called from incorrect function.

- Use jprobe_saved_regs instead getting it from stack.
  (Especially on x86-64, it may get incorrect data, because
   pt_regs can not be get by using container_of(rsp))
- Change the type of stack pointer to unsigned long *.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

parent b4be6258

arch/x86/kernel/kprobes_32.c

+1 −3

Original line number	Original line	Diff line number	Diff line
	@@ -727,9 +727,7 @@ int __kprobes longjmp_break_handler(struct kprobe p, struct pt_regs regs)

	if ((addr > (u8 ) jprobe_return) && (addr < (u8 ) jprobe_return_end)) {		if ((addr > (u8 ) jprobe_return) && (addr < (u8 ) jprobe_return_end)) {
	if (&regs->esp != kcb->jprobe_saved_esp) {		if (&regs->esp != kcb->jprobe_saved_esp) {
	struct pt_regs *saved_regs =		struct pt_regs *saved_regs = &kcb->jprobe_saved_regs;
	container_of(kcb->jprobe_saved_esp,
	struct pt_regs, esp);
	printk("current esp %p does not match saved esp %p\n",		printk("current esp %p does not match saved esp %p\n",
	&regs->esp, kcb->jprobe_saved_esp);		&regs->esp, kcb->jprobe_saved_esp);
	printk("Saved registers for jprobe %p\n", jp);		printk("Saved registers for jprobe %p\n", jp);

arch/x86/kernel/kprobes_64.c

+2 −4

Original line number	Original line	Diff line number	Diff line
	@@ -716,10 +716,8 @@ int __kprobes longjmp_break_handler(struct kprobe p, struct pt_regs regs)
	struct jprobe *jp = container_of(p, struct jprobe, kp);		struct jprobe *jp = container_of(p, struct jprobe, kp);

	if ((addr > (u8 ) jprobe_return) && (addr < (u8 ) jprobe_return_end)) {		if ((addr > (u8 ) jprobe_return) && (addr < (u8 ) jprobe_return_end)) {
	if ((long *)regs->rsp != kcb->jprobe_saved_rsp) {		if ((unsigned long *)regs->rsp != kcb->jprobe_saved_rsp) {
	struct pt_regs *saved_regs =		struct pt_regs *saved_regs = &kcb->jprobe_saved_regs;
	container_of(kcb->jprobe_saved_rsp,
	struct pt_regs, rsp);
	printk("current rsp %p does not match saved rsp %p\n",		printk("current rsp %p does not match saved rsp %p\n",
	(long *)regs->rsp, kcb->jprobe_saved_rsp);		(long *)regs->rsp, kcb->jprobe_saved_rsp);
	printk("Saved registers for jprobe %p\n", jp);		printk("Saved registers for jprobe %p\n", jp);

include/asm-x86/kprobes_32.h

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -73,7 +73,7 @@ struct kprobe_ctlblk {
	unsigned long kprobe_status;		unsigned long kprobe_status;
	unsigned long kprobe_old_eflags;		unsigned long kprobe_old_eflags;
	unsigned long kprobe_saved_eflags;		unsigned long kprobe_saved_eflags;
	long *jprobe_saved_esp;		unsigned long *jprobe_saved_esp;
	struct pt_regs jprobe_saved_regs;		struct pt_regs jprobe_saved_regs;
	kprobe_opcode_t jprobes_stack[MAX_STACK_SIZE];		kprobe_opcode_t jprobes_stack[MAX_STACK_SIZE];
	struct prev_kprobe prev_kprobe;		struct prev_kprobe prev_kprobe;

include/asm-x86/kprobes_64.h

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -66,7 +66,7 @@ struct kprobe_ctlblk {
	unsigned long kprobe_status;		unsigned long kprobe_status;
	unsigned long kprobe_old_rflags;		unsigned long kprobe_old_rflags;
	unsigned long kprobe_saved_rflags;		unsigned long kprobe_saved_rflags;
	long *jprobe_saved_rsp;		unsigned long *jprobe_saved_rsp;
	struct pt_regs jprobe_saved_regs;		struct pt_regs jprobe_saved_regs;
	kprobe_opcode_t jprobes_stack[MAX_STACK_SIZE];		kprobe_opcode_t jprobes_stack[MAX_STACK_SIZE];
	struct prev_kprobe prev_kprobe;		struct prev_kprobe prev_kprobe;