[PATCH] kprobe handler: discard user space trap
Currently kprobe handler traps only happen in kernel space, so function
kprobe_exceptions_notify should skip traps which happen in user space.
This patch modifies this, and it is based on 2.6.16-rc4.
Signed-off-by: bibo mao <bibo.mao@intel.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: "Keshavamurthy, Anil S" <anil.s.keshavamurthy@intel.com>
Cc: <hiramatu@sdl.hitachi.co.jp>
Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c
index acdcc64..df1b346 100644
--- a/arch/i386/kernel/kprobes.c
+++ b/arch/i386/kernel/kprobes.c
@@ -203,13 +203,14 @@
{
struct kprobe *p;
int ret = 0;
- kprobe_opcode_t *addr = NULL;
- unsigned long *lp;
+ kprobe_opcode_t *addr;
struct kprobe_ctlblk *kcb;
#ifdef CONFIG_PREEMPT
unsigned pre_preempt_count = preempt_count();
#endif /* CONFIG_PREEMPT */
+ addr = (kprobe_opcode_t *)(regs->eip - sizeof(kprobe_opcode_t));
+
/*
* We don't want to be preempted for the entire
* duration of kprobe processing
@@ -217,17 +218,6 @@
preempt_disable();
kcb = get_kprobe_ctlblk();
- /* Check if the application is using LDT entry for its code segment and
- * calculate the address by reading the base address from the LDT entry.
- */
- if ((regs->xcs & 4) && (current->mm)) {
- lp = (unsigned long *) ((unsigned long)((regs->xcs >> 3) * 8)
- + (char *) current->mm->context.ldt);
- addr = (kprobe_opcode_t *) (get_desc_base(lp) + regs->eip -
- sizeof(kprobe_opcode_t));
- } else {
- addr = (kprobe_opcode_t *)(regs->eip - sizeof(kprobe_opcode_t));
- }
/* Check we're not actually recursing */
if (kprobe_running()) {
p = get_kprobe(addr);
@@ -579,6 +569,9 @@
struct die_args *args = (struct die_args *)data;
int ret = NOTIFY_DONE;
+ if (args->regs && user_mode(args->regs))
+ return ret;
+
switch (val) {
case DIE_INT3:
if (kprobe_handler(args->regs))
diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index 50ae8c7..45b8479 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -740,6 +740,9 @@
struct die_args *args = (struct die_args *)data;
int ret = NOTIFY_DONE;
+ if (args->regs && user_mode(args->regs))
+ return ret;
+
switch(val) {
case DIE_BREAK:
/* err is break number from ia64_bad_break() */
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index cb1fe58..aea25dd 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -396,6 +396,9 @@
struct die_args *args = (struct die_args *)data;
int ret = NOTIFY_DONE;
+ if (args->regs && user_mode(args->regs))
+ return ret;
+
switch (val) {
case DIE_BPT:
if (kprobe_handler(args->regs))
diff --git a/arch/sparc64/kernel/kprobes.c b/arch/sparc64/kernel/kprobes.c
index b9a9ce70..d91c3187 100644
--- a/arch/sparc64/kernel/kprobes.c
+++ b/arch/sparc64/kernel/kprobes.c
@@ -324,6 +324,9 @@
struct die_args *args = (struct die_args *)data;
int ret = NOTIFY_DONE;
+ if (args->regs && user_mode(args->regs))
+ return ret;
+
switch (val) {
case DIE_DEBUG:
if (kprobe_handler(args->regs))
diff --git a/arch/x86_64/kernel/kprobes.c b/arch/x86_64/kernel/kprobes.c
index 14f0ced..218e015 100644
--- a/arch/x86_64/kernel/kprobes.c
+++ b/arch/x86_64/kernel/kprobes.c
@@ -601,6 +601,9 @@
struct die_args *args = (struct die_args *)data;
int ret = NOTIFY_DONE;
+ if (args->regs && user_mode(args->regs))
+ return ret;
+
switch (val) {
case DIE_INT3:
if (kprobe_handler(args->regs))
