ftrace: Keep address offset in ftrace_lookup_symbols

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 <[email protected]>
Acked-by: Steven Rostedt (Google) <[email protected]>
Fixes: bed0d9a50dac ("ftrace: Add ftrace_lookup_symbols function")
Signed-off-by: Jiri Olsa <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>

1 files changed, 11 insertions, 2 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index e750fe141a60..601ccf1b2f09 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -8029,15 +8029,23 @@ static int kallsyms_callback(void *data, const char *name,
 			     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;
 }
 
@@ -8062,6 +8070,7 @@ int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *a
 	struct kallsyms_data args;
 	int err;
 
+	memset(addrs, 0, sizeof(*addrs) * cnt);
 	args.addrs = addrs;
 	args.syms = sorted_syms;
 	args.cnt = cnt;