During ftrace_init(), if an early kprobe has already probed at an
instruction, don't fire ftrace_bug(). Instead,
kprobe_fix_ftrace_make_nop() is for this fixing. It calls
arch_fix_ftrace_early_kprobe() to adjust arch specific data. Following
patches will convert such kprobes into ftrace.
It's kprobe's responsibility for setting and clearing
FTRACE_FL_EARLY_KPROBES flag. When ftrace try to makenop, set this flag.
When ftrace try to create call instruction on it, unset it.
Signed-off-by: Wang Nan <wangn...@huawei.com>
---
include/linux/ftrace.h | 5 +++--
include/linux/kprobes.h | 7 +++++++
kernel/kprobes.c | 39 +++++++++++++++++++++++++++++++++++++++
kernel/trace/ftrace.c | 17 ++++++++++++-----
4 files changed, 61 insertions(+), 7 deletions(-)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 8db315a..fe99166 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -341,10 +341,11 @@ enum {
FTRACE_FL_TRAMP = (1UL << 28),
FTRACE_FL_TRAMP_EN = (1UL << 27),
FTRACE_FL_IPMODIFY = (1UL << 26),
+ FTRACE_FL_EARLY_KPROBES = (1UL << 25),
};
-#define FTRACE_REF_MAX_SHIFT 26
-#define FTRACE_FL_BITS 6
+#define FTRACE_REF_MAX_SHIFT 25
+#define FTRACE_FL_BITS 7
#define FTRACE_FL_MASKED_BITS ((1UL << FTRACE_FL_BITS) - 1)
#define FTRACE_FL_MASK (FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT)
#define FTRACE_REF_MAX ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index f8f2ac2..ab1a330 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -282,10 +282,17 @@ extern void arch_fix_ftrace_early_kprobe(struct kprobe
*kp,
struct optimized_kprobe *op, int optimized);
extern void init_kprobes_on_ftrace(void);
+extern bool kprobe_fix_ftrace_make_nop(struct dyn_ftrace *rec);
#else
static inline void init_kprobes_on_ftrace(void)
{
}
+
+static inline bool kprobe_fix_ftrace_make_nop(struct dyn_ftrace *_unused)
+{
+
+ return false;
+}
#endif // CONFIG_EARLY_KPROBES && CONFIG_KPROBES_ON_FTRACE
#ifdef CONFIG_EARLY_KPROBES
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index b5e13ba..20b6ab8 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2584,6 +2584,45 @@ module_init(init_kprobes);
EXPORT_SYMBOL_GPL(jprobe_return);
#if defined(CONFIG_KPROBES_ON_FTRACE) && defined(CONFIG_EARLY_KPROBES)
+bool kprobe_fix_ftrace_make_nop(struct dyn_ftrace *rec)
+{
+ struct optimized_kprobe *op;
+ struct kprobe *kp;
+ int optimized;
+ void *addr;
+
+ if (kprobes_on_ftrace_initialized)
+ return false;
+
+ addr = (void *)rec->ip;
+ mutex_lock(&kprobe_mutex);
+ kp = get_kprobe(addr);
+
+ if (!kp || !(kp->flags & KPROBE_FLAG_FTRACE_EARLY)) {
+ mutex_unlock(&kprobe_mutex);
+ return false;
+ }
+
+ op = kprobe_aggrprobe(kp) ?
+ container_of(kp, struct optimized_kprobe, kp)
+ : NULL;
+
+ optimized = op ? op->kp.flags & KPROBE_FLAG_OPTIMIZED : 0;
+ arch_fix_ftrace_early_kprobe(kp, op, optimized);
+ if (op != NULL) {
+ struct kprobe *list_p;
+
+ /* Fix all kprobes connected to it */
+ list_for_each_entry_rcu(list_p, &op->kp.list, list)
+ arch_fix_ftrace_early_kprobe(list_p, NULL, optimized);
+ }
+
+ mutex_unlock(&kprobe_mutex);
+
+ rec->flags |= FTRACE_FL_EARLY_KPROBES;
+ return true;
+}
+
void init_kprobes_on_ftrace(void)
{
kprobes_on_ftrace_initialized = true;
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 5cb0269..78787d4 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2387,11 +2387,18 @@ ftrace_code_disable(struct module *mod, struct
dyn_ftrace *rec)
return 0;
ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
- if (ret) {
- ftrace_bug(ret, rec);
- return 0;
- }
- return 1;
+
+ if (!ret)
+ return 1;
+
+#if defined(CONFIG_KPROBES_ON_FTRACE) && defined(CONFIG_EARLY_KPROBES)
+ /* FTRACE_FL_EARLY_KPROBES should have been set for rec */
+ if (kprobe_fix_ftrace_make_nop(rec))
+ return 1;
+#endif
+
+ ftrace_bug(ret, rec);
+ return 0;
}
/*
--
1.8.4
--
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