[PATCH v21 20/20] bpf: Use ftrace_get_symaddr() for kprobe_multi probes

Masami Hiramatsu (Google)
2024-12-10T02:13:03Z

Add ftrace_get_entry_ip() which is only for ftrace based probes, and use
it for kprobe multi probes because they are based on fprobe which uses
ftrace instead of kprobes.

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
Changes in v21:
- Use new ftreace_get_symaddr() only for kprobe multi probes.
Changes in v19:
- Use ftrace_get_symaddr() instead of introducing new arch dependent code.
- Also, replace x86 code with ftrace_get_symaddr(), which does the same
thing.
---
kernel/trace/bpf_trace.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 852400170c5c..91c18e9aac6b 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1070,6 +1070,13 @@ static unsigned long get_entry_ip(unsigned long fentry_ip)
#define get_entry_ip(fentry_ip) fentry_ip
#endif

+static unsigned long ftrace_get_entry_ip(unsigned long fentry_ip)
+{
+ unsigned long ip = ftrace_get_symaddr(fentry_ip);
+
+ return ip ? : fentry_ip;
+}
+
BPF_CALL_1(bpf_get_func_ip_kprobe, struct pt_regs *, regs)
{
struct bpf_trace_run_ctx *run_ctx __maybe_unused;
@@ -2818,7 +2825,8 @@ kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip,
int err;

link = container_of(fp, struct bpf_kprobe_multi_link, fp);
- err = kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), fregs, false, data);
+ err = kprobe_multi_link_prog_run(link, ftrace_get_entry_ip(fentry_ip),
+ fregs, false, data);
return is_kprobe_session(link->link.prog) ? err : 0;
}

@@ -2830,7 +2838,8 @@ kprobe_multi_link_exit_handler(struct fprobe *fp, unsigned long fentry_ip,
struct bpf_kprobe_multi_link *link;

link = container_of(fp, struct bpf_kprobe_multi_link, fp);
- kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), fregs, true, data);
+ kprobe_multi_link_prog_run(link, ftrace_get_entry_ip(fentry_ip),
+ fregs, true, data);
}

static int symbols_cmp_r(const void *a, const void *b, const void *priv)