fprobe: Pass return address to the handlers
authorMasami Hiramatsu (Google) <mhiramat@kernel.org>
Tue, 6 Jun 2023 12:39:55 +0000 (21:39 +0900)
committerMasami Hiramatsu (Google) <mhiramat@kernel.org>
Tue, 6 Jun 2023 12:39:55 +0000 (21:39 +0900)
Pass return address as 'ret_ip' to the fprobe entry and return handlers
so that the fprobe user handler can get the reutrn address without
analyzing arch-dependent pt_regs.

Link: https://lore.kernel.org/all/168507467664.913472.11642316698862778600.stgit@mhiramat.roam.corp.google.com/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
include/linux/fprobe.h
include/linux/rethook.h
kernel/kprobes.c
kernel/trace/bpf_trace.c
kernel/trace/fprobe.c
kernel/trace/rethook.c
lib/test_fprobe.c
samples/fprobe/fprobe_example.c

index 47fefc7f363bf35539367ac29add3d31d6ba6dac..134f0f59ffa8168bb4c35ad403b9b3b254fb7c44 100644 (file)
@@ -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. */
index c8ac1e5afcd1de4ad5613a5cbcaff767cc23b28e..fdf26cd0e7424e29a3552b515980d1455b6461cd 100644 (file)
@@ -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.
index 00e177de91ccd501f0cdaa3ec66009bb44bad74f..ce13f1a352514b23341ade70fa748dd9f9fb2750 100644 (file)
@@ -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;
index 9a050e36dc6c2e5b9389dbe36576cc2c1545ddc4..987c76d94604788d2de36fdcaeb28857cd8e8ba0 100644 (file)
@@ -2642,7 +2642,8 @@ 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;
 
@@ -2653,7 +2654,8 @@ 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;
 
index 18d36842faf575d2057439aa22f5b8b4064858af..32994815edf6755214fe56bbc3a3e851f7ccefab 100644 (file)
@@ -46,7 +46,7 @@ static inline 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) {
@@ -112,7 +112,7 @@ 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;
@@ -133,7 +133,7 @@ static void fprobe_exit_handler(struct rethook_node *rh, void *data,
                return;
        }
 
-       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);
        ftrace_test_recursion_unlock(bit);
 }
index 60f6cb2b486bf466227ca2ac68070349e07556e7..f32ee484391adfc80f7727db903a5de3d09fe3f3 100644 (file)
@@ -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;
index 079435a2e26c42aaf7a331cc58bcc3278520ceaa..24de0e5ff85998c9d927719f4452b129e1cc0e62 100644 (file)
@@ -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);
index 4efc8feb6277dd33b608fcf32a765fe9f3ba04bb..64e715e7ed11df4b9f46de87f1fbafa666daf6e2 100644 (file)
@@ -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)
                /*