[PATCHv3 bpf-next 2/8] ftrace: Add support to resolve module symbols in ftrace_lookup_symbols

Jiri Olsa
2022-10-25T13:42:19Z

Currently ftrace_lookup_symbols iterates only over core symbols,
adding module_kallsyms_on_each_symbol call to check on modules
symbols as well.

Also removing 'args.found == args.cnt' condition, because it's
already checked in kallsyms_callback function.

Also removing 'err < 0' check, because both *kallsyms_on_each_symbol
functions do not return error.

Reported-by: Martynas Pumputis <m@lambda.lt>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
kernel/trace/ftrace.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index fbf2543111c0..72de9009a6a0 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -8267,6 +8267,10 @@ struct kallsyms_data {
size_t found;
};

+/* This function gets called for all kernel and module symbols
+ * and returns 1 in case we resolved all the requested symbols,
+ * 0 otherwise.
+ */
static int kallsyms_callback(void *data, const char *name,
struct module *mod, unsigned long addr)
{
@@ -8309,17 +8313,19 @@ static int kallsyms_callback(void *data, const char *name,
int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
{
struct kallsyms_data args;
- int err;
+ int found_all;

memset(addrs, 0, sizeof(*addrs) * cnt);
args.addrs = addrs;
args.syms = sorted_syms;
args.cnt = cnt;
args.found = 0;
- err = kallsyms_on_each_symbol(kallsyms_callback, &args);
- if (err < 0)
- return err;
- return args.found == args.cnt ? 0 : -ESRCH;
+
+ found_all = kallsyms_on_each_symbol(kallsyms_callback, &args);
+ if (found_all)
+ return 0;
+ found_all = module_kallsyms_on_each_symbol(kallsyms_callback, &args);
+ return found_all ? 0 : -ESRCH;
}

#ifdef CONFIG_SYSCTL
--
2.37.3