[PATCH v11 01/11] fprobe: Pass return address to the handlers
From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Date: 2023-05-17 11:00:30
Also in:
bpf, lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [security & lsm] (security audit and enforcement using bpf), bpf [tracing], kprobes, library code, the rest, tracing · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, KP Singh, Matt Bobrowski, Song Liu, Naveen N Rao, "David S. Miller", Masami Hiramatsu, Andrew Morton, Linus Torvalds, Steven Rostedt
From: Masami Hiramatsu (Google) <mhiramat@kernel.org> 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. Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> --- Changes in v10: - Add the reason why this requires in patch description. --- 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) /*