~15 years ago kprobes grew the 'arch_deref_entry_point()' __weak function:
3d7e33825d87: ("jprobes: make jprobes a little safer for users")
But this is just open-coded dereference_symbol_descriptor() in essence, and
its obscure nature was causing bugs.
Just use the real thing and remove arch_deref_entry_point().
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Tested-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
---
Changes in v9:
- Update changelog according to Ingo's suggestion.
Changes in v6:
- Use dereference_symbol_descriptor() so that it can handle address in
modules correctly.
---
arch/ia64/kernel/kprobes.c | 5 -----
arch/powerpc/kernel/kprobes.c | 11 -----------
include/linux/kprobes.h | 1 -
kernel/kprobes.c | 7 +------
lib/error-inject.c | 3 ++-
5 files changed, 3 insertions(+), 24 deletions(-)
diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index d4048518a1d7..0f8573bbf520 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -891,11 +891,6 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
return ret;
}
-unsigned long arch_deref_entry_point(void *entry)
-{
- return ((struct fnptr *)entry)->ip;
-}
-
static struct kprobe trampoline_p = {
.pre_handler = trampoline_probe_handler
};
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index cbc28d1a2e1b..077ab73e6e56 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -541,17 +541,6 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
}
NOKPROBE_SYMBOL(kprobe_fault_handler);
-unsigned long arch_deref_entry_point(void *entry)
-{
-#ifdef PPC64_ELF_ABI_v1
- if (!kernel_text_address((unsigned long)entry))
- return ppc_global_function_entry(entry);
- else
-#endif
- return (unsigned long)entry;
-}
-NOKPROBE_SYMBOL(arch_deref_entry_point);
-
static struct kprobe trampoline_p = {
.addr = (kprobe_opcode_t *) &kretprobe_trampoline,
.pre_handler = trampoline_probe_handler
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 7d0d21f2315a..c9e0c13db84a 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -378,7 +378,6 @@ int register_kprobe(struct kprobe *p);
void unregister_kprobe(struct kprobe *p);
int register_kprobes(struct kprobe **kps, int num);
void unregister_kprobes(struct kprobe **kps, int num);
-unsigned long arch_deref_entry_point(void *);
int register_kretprobe(struct kretprobe *rp);
void unregister_kretprobe(struct kretprobe *rp);
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 2029d7ceaa11..2540cd56fa81 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1866,11 +1866,6 @@ static struct notifier_block kprobe_exceptions_nb = {
.priority = 0x7fffffff /* we need to be notified first */
};
-unsigned long __weak arch_deref_entry_point(void *entry)
-{
- return (unsigned long)entry;
-}
-
#ifdef CONFIG_KRETPROBES
unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
@@ -2332,7 +2327,7 @@ static int __init populate_kprobe_blacklist(unsigned long *start,
int ret;
for (iter = start; iter < end; iter++) {
- entry = arch_deref_entry_point((void *)*iter);
+ entry = (unsigned long)dereference_symbol_descriptor((void *)*iter);
ret = kprobe_add_ksym_blacklist(entry);
if (ret == -EINVAL)
continue;
diff --git a/lib/error-inject.c b/lib/error-inject.c
index c73651b15b76..2ff5ef689d72 100644
--- a/lib/error-inject.c
+++ b/lib/error-inject.c
@@ -8,6 +8,7 @@
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/slab.h>
+#include <asm/sections.h>
/* Whitelist of symbols that can be overridden for error injection. */
static LIST_HEAD(error_injection_list);
@@ -64,7 +65,7 @@ static void populate_error_injection_list(struct error_injection_entry *start,
mutex_lock(&ei_mutex);
for (iter = start; iter < end; iter++) {
- entry = arch_deref_entry_point((void *)iter->addr);
+ entry = (unsigned long)dereference_symbol_descriptor((void *)iter->addr);
if (!kernel_text_address(entry) ||
!kallsyms_lookup_size_offset(entry, &size, &offset)) {
