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.
Cc: Francis Laniel <flaniel@xxxxxxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Fixes: b022f0c7e404 ("tracing/kprobes: Return EADDRNOTAVAIL when func matches several symbols")
Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
---
kernel/trace/trace_kprobe.c | 24 ++++++++++++++++++++----
1 file changed, 20 insertions(+), 4 deletions(-)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index effcaede4759..1efb27f35963 100644
--- 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[])
--
2.34.1
