bpf: Use RCU in all users of __module_text_address().

__module_address() can be invoked within a RCU section, there is no
requirement to have preemption disabled.

Replace the preempt_disable() section around __module_address() with
RCU.

Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matt Bobrowski <mattbobrowski@google.com>
Cc: Song Liu <song@kernel.org>
Cc: Stanislav Fomichev <sdf@fomichev.me>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: bpf@vger.kernel.org
Cc: linux-trace-kernel@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20250129084751.tH6iidUO@linutronix.de
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index adc947587eb8132ebbd54778d2db937b3b8861de..e6a17a60d8787c26a6513d645dc4dd5ac4a97f7e 100644 (file)
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2345,10 +2345,9 @@ void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp)
 {
        struct module *mod;
 
-       preempt_disable();
+       guard(rcu)();
        mod = __module_address((unsigned long)btp);
        module_put(mod);
-       preempt_enable();
 }
 
 static __always_inline
@@ -2932,18 +2931,21 @@ static int get_modules_for_addrs(struct module ***mods, unsigned long *addrs, u3
        u32 i, err = 0;
 
        for (i = 0; i < addrs_cnt; i++) {
+               bool skip_add = false;
                struct module *mod;
 
-               preempt_disable();
-               mod = __module_address(addrs[i]);
-               /* Either no module or we it's already stored  */
-               if (!mod || has_module(&arr, mod)) {
-                       preempt_enable();
-                       continue;
+               scoped_guard(rcu) {
+                       mod = __module_address(addrs[i]);
+                       /* Either no module or it's already stored  */
+                       if (!mod || has_module(&arr, mod)) {
+                               skip_add = true;
+                               break; /* scoped_guard */
+                       }
+                       if (!try_module_get(mod))
+                               err = -EINVAL;
                }
-               if (!try_module_get(mod))
-                       err = -EINVAL;
-               preempt_enable();
+               if (skip_add)
+                       continue;
                if (err)
                        break;
                err = add_module(&arr, mod);