From: Andrii Nakryiko andrii@kernel.org
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 (cherry picked from commit 926fe783c8a64b33997fec405cf1af3e61aed441) --- 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 a34a4fcdab7b..de11845df6d1 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[])