tracing/kprobes: Fix symbol counting logic by looking at modules as well

Recent changes to count number of matching symbols when creating
a kprobe event failed to take into account kernel modules. As such, it
breaks kprobes on kernel module symbols, by assuming there is no match.

Fix this my calling module_kallsyms_on_each_symbol() in addition to
kallsyms_on_each_match_symbol() to perform a proper counting.

Link: https://lore.kernel.org/all/20231027233126.2073148-1-andrii@kernel.org/
Cc: Francis Laniel <flaniel@linux.microsoft.com>
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Fixes: b022f0c7e404 ("tracing/kprobes: Return EADDRNOTAVAIL when func matches several symbols")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 95c5b06..e834f14 100644 (file)
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -714,14 +714,30 @@ static int count_symbols(void *data, unsigned long unused)
        return 0;
 }
 
+struct sym_count_ctx {
+       unsigned int count;
+       const char *name;
+};
+
+static int count_mod_symbols(void *data, const char *name, unsigned long unused)
+{
+       struct sym_count_ctx *ctx = data;
+
+       if (strcmp(name, ctx->name) == 0)
+               ctx->count++;
+
+       return 0;
+}
+
 static unsigned int number_of_same_symbols(char *func_name)
 {
-       unsigned int count;
+       struct sym_count_ctx ctx = { .count = 0, .name = func_name };
+
+       kallsyms_on_each_match_symbol(count_symbols, func_name, &ctx.count);
 
-       count = 0;
-       kallsyms_on_each_match_symbol(count_symbols, func_name, &count);
+       module_kallsyms_on_each_symbol(NULL, count_mod_symbols, &ctx);
 
-       return count;
+       return ctx.count;
 }
 
 static int __trace_kprobe_create(int argc, const char *argv[])