From: Jiri Olsa <jolsa@kernel.org>
Date: Wed, 15 Jun 2022 13:21:16 +0200
Subject: ftrace: Keep address offset in ftrace_lookup_symbols
Patch-mainline: v5.19-rc4
Git-commit: eb1b2985fe5c5f02e43e4c0d47bbe7ed835007f3
References: jsc#PED-1377

We want to store the resolved address on the same index as
the symbol string, because that's the user (bpf kprobe link)
code assumption.

Also making sure we don't store duplicates that might be
present in kallsyms.

Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Fixes: bed0d9a50dac ("ftrace: Add ftrace_lookup_symbols function")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220615112118.497303-3-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
 kernel/trace/ftrace.c |   13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -7692,15 +7692,23 @@ static int kallsyms_callback(void *data,
 			     struct module *mod, unsigned long addr)
 {
 	struct kallsyms_data *args = data;
+	const char **sym;
+	int idx;
 
-	if (!bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp))
+	sym = bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp);
+	if (!sym)
+		return 0;
+
+	idx = sym - args->syms;
+	if (args->addrs[idx])
 		return 0;
 
 	addr = ftrace_location(addr);
 	if (!addr)
 		return 0;
 
-	args->addrs[args->found++] = addr;
+	args->addrs[idx] = addr;
+	args->found++;
 	return args->found == args->cnt ? 1 : 0;
 }
 
@@ -7725,6 +7733,7 @@ int ftrace_lookup_symbols(const char **s
 	struct kallsyms_data args;
 	int err;
 
+	memset(addrs, 0, sizeof(*addrs) * cnt);
 	args.addrs = addrs;
 	args.syms = sorted_syms;
 	args.cnt = cnt;