[PATCH v9.1 01/11] fprobe: Pass return address to the handlers

Masami Hiramatsu (Google)
2023-05-02T02:17:37Z

Pass return address as 'ret_ip' to the fprobe entry and return handlers.

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
include/linux/fprobe.h | 6 ++++--
include/linux/rethook.h | 2 +-
kernel/kprobes.c | 1 +
kernel/trace/bpf_trace.c | 6 ++++--
kernel/trace/fprobe.c | 6 +++---
kernel/trace/rethook.c | 3 ++-
lib/test_fprobe.c | 10 +++++++---
samples/fprobe/fprobe_example.c | 6 ++++--
8 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/include/linux/fprobe.h b/include/linux/fprobe.h
index 47fefc7f363b..134f0f59ffa8 100644
--- a/include/linux/fprobe.h
+++ b/include/linux/fprobe.h
@@ -35,9 +35,11 @@ struct fprobe {
int nr_maxactive;

int (*entry_handler)(struct fprobe *fp, unsigned long entry_ip,
- struct pt_regs *regs, void *entry_data);
+ unsigned long ret_ip, struct pt_regs *regs,
+ void *entry_data);
void (*exit_handler)(struct fprobe *fp, unsigned long entry_ip,
- struct pt_regs *regs, void *entry_data);
+ unsigned long ret_ip, struct pt_regs *regs,
+ void *entry_data);
};

/* This fprobe is soft-disabled. */
diff --git a/include/linux/rethook.h b/include/linux/rethook.h
index c8ac1e5afcd1..fdf26cd0e742 100644
--- a/include/linux/rethook.h
+++ b/include/linux/rethook.h
@@ -14,7 +14,7 @@

struct rethook_node;

-typedef void (*rethook_handler_t) (struct rethook_node *, void *, struct pt_regs *);
+typedef void (*rethook_handler_t) (struct rethook_node *, void *, unsigned long, struct pt_regs *);

/**
* struct rethook - The rethook management data structure.
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 00e177de91cc..ce13f1a35251 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2127,6 +2127,7 @@ static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
NOKPROBE_SYMBOL(pre_handler_kretprobe);

static void kretprobe_rethook_handler(struct rethook_node *rh, void *data,
+ unsigned long ret_addr,
struct pt_regs *regs)
{
struct kretprobe *rp = (struct kretprobe *)data;
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index d804172b709c..c0a32118f08f 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2646,7 +2646,8 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link,

static int
kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip,
- struct pt_regs *regs, void *data)
+ unsigned long ret_ip, struct pt_regs *regs,
+ void *data)
{
struct bpf_kprobe_multi_link *link;

@@ -2657,7 +2658,8 @@ kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip,

static void
kprobe_multi_link_exit_handler(struct fprobe *fp, unsigned long fentry_ip,
- struct pt_regs *regs, void *data)
+ unsigned long ret_ip, struct pt_regs *regs,
+ void *data)
{
struct bpf_kprobe_multi_link *link;

diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index 9abb3905bc8e..973bc664fcc1 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -52,7 +52,7 @@ static void fprobe_handler(unsigned long ip, unsigned long parent_ip,
}

if (fp->entry_handler)
- ret = fp->entry_handler(fp, ip, ftrace_get_regs(fregs), entry_data);
+ ret = fp->entry_handler(fp, ip, parent_ip, ftrace_get_regs(fregs), entry_data);

/* If entry_handler returns !0, nmissed is not counted. */
if (rh) {
@@ -81,7 +81,7 @@ static void fprobe_kprobe_handler(unsigned long ip, unsigned long parent_ip,
}

static void fprobe_exit_handler(struct rethook_node *rh, void *data,
- struct pt_regs *regs)
+ unsigned long ret_ip, struct pt_regs *regs)
{
struct fprobe *fp = (struct fprobe *)data;
struct fprobe_rethook_node *fpr;
@@ -91,7 +91,7 @@ static void fprobe_exit_handler(struct rethook_node *rh, void *data,

fpr = container_of(rh, struct fprobe_rethook_node, node);

- fp->exit_handler(fp, fpr->entry_ip, regs,
+ fp->exit_handler(fp, fpr->entry_ip, ret_ip, regs,
fp->entry_data_size ? (void *)fpr->data : NULL);
}
NOKPROBE_SYMBOL(fprobe_exit_handler);
diff --git a/kernel/trace/rethook.c b/kernel/trace/rethook.c
index 32c3dfdb4d6a..fc196e186737 100644
--- a/kernel/trace/rethook.c
+++ b/kernel/trace/rethook.c
@@ -301,7 +301,8 @@ unsigned long rethook_trampoline_handler(struct pt_regs *regs,
break;
handler = READ_ONCE(rhn->rethook->handler);
if (handler)
- handler(rhn, rhn->rethook->data, regs);
+ handler(rhn, rhn->rethook->data,
+ correct_ret_addr, regs);

if (first == node)
break;
diff --git a/lib/test_fprobe.c b/lib/test_fprobe.c
index 0fe5273e960b..ade7e3d93dac 100644
--- a/lib/test_fprobe.c
+++ b/lib/test_fprobe.c
@@ -39,7 +39,8 @@ static noinline u32 fprobe_selftest_nest_target(u32 value, u32 (*nest)(u32))
}

static notrace int fp_entry_handler(struct fprobe *fp, unsigned long ip,
- struct pt_regs *regs, void *data)
+ unsigned long ret_ip,
+ struct pt_regs *regs, void *data)
{
KUNIT_EXPECT_FALSE(current_test, preemptible());
/* This can be called on the fprobe_selftest_target and the fprobe_selftest_target2 */
@@ -57,6 +58,7 @@ static notrace int fp_entry_handler(struct fprobe *fp, unsigned long ip,
}

static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip,
+ unsigned long ret_ip,
struct pt_regs *regs, void *data)
{
unsigned long ret = regs_return_value(regs);
@@ -78,14 +80,16 @@ static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip,
}

static notrace int nest_entry_handler(struct fprobe *fp, unsigned long ip,
- struct pt_regs *regs, void *data)
+ unsigned long ret_ip,
+ struct pt_regs *regs, void *data)
{
KUNIT_EXPECT_FALSE(current_test, preemptible());
return 0;
}

static notrace void nest_exit_handler(struct fprobe *fp, unsigned long ip,
- struct pt_regs *regs, void *data)
+ unsigned long ret_ip,
+ struct pt_regs *regs, void *data)
{
KUNIT_EXPECT_FALSE(current_test, preemptible());
KUNIT_EXPECT_EQ(current_test, ip, target_nest_ip);
diff --git a/samples/fprobe/fprobe_example.c b/samples/fprobe/fprobe_example.c
index 4efc8feb6277..64e715e7ed11 100644
--- a/samples/fprobe/fprobe_example.c
+++ b/samples/fprobe/fprobe_example.c
@@ -49,6 +49,7 @@ static void show_backtrace(void)
}

static int sample_entry_handler(struct fprobe *fp, unsigned long ip,
+ unsigned long ret_ip,
struct pt_regs *regs, void *data)
{
if (use_trace)
@@ -65,10 +66,11 @@ static int sample_entry_handler(struct fprobe *fp, unsigned long ip,
return 0;
}

-static void sample_exit_handler(struct fprobe *fp, unsigned long ip, struct pt_regs *regs,
+static void sample_exit_handler(struct fprobe *fp, unsigned long ip,
+ unsigned long ret_ip, struct pt_regs *regs,
void *data)
{
- unsigned long rip = instruction_pointer(regs);
+ unsigned long rip = ret_ip;

if (use_trace)
/*