diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c index 4acdab165793..af7d6e2060d9 100644 --- a/kernel/trace/trace_fprobe.c +++ b/kernel/trace/trace_fprobe.c @@ -888,9 +888,15 @@ static void __find_tracepoint_module_cb(struct tracepoint *tp, struct module *mo struct __find_tracepoint_cb_data *data = priv; if (!data->tpoint && !strcmp(data->tp_name, tp->name)) { - data->tpoint = tp; - if (!data->mod) + /* If module is not specified, try getting module refcount. */ + if (!data->mod && mod) { + /* If failed to get refcount, ignore this tracepoint. */ + if (!try_module_get(mod)) + return; + data->mod = mod; + } + data->tpoint = tp; } } @@ -902,7 +908,11 @@ static void __find_tracepoint_cb(struct tracepoint *tp, void *priv) data->tpoint = tp; } -/* Find a tracepoint from kernel and module. */ +/* + * Find a tracepoint from kernel and module. If the tracepoint is on the module, + * the module's refcount is incremented and returned as *@tp_mod. Thus, if it is + * not NULL, caller must call module_put(*tp_mod) after used the tracepoint. + */ static struct tracepoint *find_tracepoint(const char *tp_name, struct module **tp_mod) { @@ -931,7 +941,10 @@ static void reenable_trace_fprobe(struct trace_fprobe *tf) } } -/* Find a tracepoint from specified module. */ +/* + * Find a tracepoint from specified module. In this case, this does not get the + * module's refcount. The caller must ensure the module is not freed. + */ static struct tracepoint *find_tracepoint_in_module(struct module *mod, const char *tp_name) { @@ -1167,11 +1180,6 @@ static int __trace_fprobe_create(int argc, const char *argv[]) if (is_tracepoint) { ctx.flags |= TPARG_FL_TPOINT; tpoint = find_tracepoint(symbol, &tp_mod); - /* lock module until register this tprobe. */ - if (tp_mod && !try_module_get(tp_mod)) { - tpoint = NULL; - tp_mod = NULL; - } if (tpoint) { ctx.funcname = kallsyms_lookup( (unsigned long)tpoint->probestub,