linux-kernel - [for-next][PATCH] bpf: Use ftrace_get_symaddr() for kprobe

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Message-ID: <20250114211815.589e01f2@gandalf.local.home>
Date: Tue, 14 Jan 2025 21:18:15 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Masami Hiramatsu <mhiramat@...nel.org>, Mark Rutland
 <mark.rutland@....com>, Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Subject: [for-next][PATCH] bpf: Use ftrace_get_symaddr() for kprobe_multi
 probes

  git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
ftrace/for-next

Head SHA1: 4f7caaa2f92b47e9d27d85f8a60bb7634becd669


Masami Hiramatsu (Google) (1):
      bpf: Use ftrace_get_symaddr() for kprobe_multi probes

----
 kernel/trace/bpf_trace.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)
---------------------------
commit 4f7caaa2f92b47e9d27d85f8a60bb7634becd669
Author: Masami Hiramatsu (Google) <mhiramat@...nel.org>
Date:   Wed Jan 1 01:00:14 2025 +0900

    bpf: Use ftrace_get_symaddr() for kprobe_multi probes
    
    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.
    
    Cc: Alexei Starovoitov <alexei.starovoitov@...il.com>
    Cc: Florent Revest <revest@...omium.org>
    Cc: Martin KaFai Lau <martin.lau@...ux.dev>
    Cc: bpf <bpf@...r.kernel.org>
    Cc: Alexei Starovoitov <ast@...nel.org>
    Cc: Jiri Olsa <jolsa@...nel.org>
    Cc: Alan Maguire <alan.maguire@...cle.com>
    Cc: Mark Rutland <mark.rutland@....com>
    Link: https://lore.kernel.org/173566081414.878879.10631096557346094362.stgit@devnote2
    Signed-off-by: Masami Hiramatsu (Google) <mhiramat@...nel.org>
    Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 863351559334..9bfd52913a5b 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2591,6 +2591,13 @@ static DEFINE_PER_CPU(struct pt_regs, bpf_kprobe_multi_pt_regs);
 #define bpf_kprobe_multi_pt_regs_ptr()	(NULL)
 #endif
 
+static unsigned long ftrace_get_entry_ip(unsigned long fentry_ip)
+{
+	unsigned long ip = ftrace_get_symaddr(fentry_ip);
+
+	return ip ? : fentry_ip;
+}
+
 static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms, u32 cnt)
 {
 	unsigned long __user usymbol;
@@ -2829,7 +2836,8 @@ 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;
 }
 
@@ -2841,7 +2849,8 @@ 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)