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Subject[PATCH 3/3] x86: WARN_ON breakpoints from .kprobes.text section
Identify breakpoints in .kprobes.text section. These certainly aren't kprobe traps. However, we make an exception for the breakpoint hardcoded into jprobe_return.

Signed-off-by: Abhishek Sagar <sagar.abhishek@gmail.com>
---

diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index 45f2949..f3d13d0 100644
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -961,6 +961,7 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data)
{
struct die_args *args = data;
+ unsigned long addr = kprobe_bkpt_addr(args->regs);
int ret = NOTIFY_DONE;

if (args->regs && user_mode_vm(args->regs))
@@ -968,7 +969,14 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,

switch (val) {
case DIE_INT3:
- if (kprobe_handler(args->regs))
+ if (in_kprobes_functions(addr) &&
+ !is_jprobe_bkpt((u8 *)addr)) {
+ /* A breakpoint has made it's way to the .kprobes.text
+ * section (excluding jprobe_return). This could be
+ * due to an external debugger. */
+ WARN_ON(1);
+
+ } else if (kprobe_handler(args->regs))
ret = NOTIFY_STOP;
break;
case DIE_DEBUG:

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