[for-next][PATCH] bpf: Use ftrace_get_symaddr() for kprobe_multi probes

From: Steven Rostedt
Date: Tue Jan 14 2025 - 21:18:20 EST


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@xxxxxxxxxx>
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@xxxxxxxxx>
Cc: Florent Revest <revest@xxxxxxxxxxxx>
Cc: Martin KaFai Lau <martin.lau@xxxxxxxxx>
Cc: bpf <bpf@xxxxxxxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Alan Maguire <alan.maguire@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Link: https://lore.kernel.org/173566081414.878879.10631096557346094362.stgit@devnote2
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>

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)