From: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx> Subject: dynamic_debug: use pointer comparison in ddebug_remove_module Now that we store the passed-in string directly in ddebug_add_module, we can use pointer equality instead of strcmp. This is a little more efficient, but more importantly, this also makes the code somewhat more correct: Currently, if one loads and then unloads a module whose name happens to match the KBUILD_MODNAME of some built-in functionality (which need not even be modular at all), all of their dynamic debug entries vanish along with those of the actual module. For example, loading and unloading a core.ko hides all pr_debugs from drivers/base/core.c and other built-in files called core.c (incidentally, there is an in-tree module whose name is core, but I just tested this with an out-of-tree trivial one). Link: http://lkml.kernel.org/r/20190212214150.4807-7-linux@xxxxxxxxxxxxxxxxxx Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx> Acked-by: Jason Baron <jbaron@xxxxxxxxxx> Cc: David Sterba <dsterba@xxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Petr Mladek <pmladek@xxxxxxxx> Cc: "Rafael J . Wysocki" <rafael.j.wysocki@xxxxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- --- a/lib/dynamic_debug.c~dynamic_debug-use-pointer-comparison-in-ddebug_remove_module +++ a/lib/dynamic_debug.c @@ -929,9 +929,10 @@ int ddebug_remove_module(const char *mod mutex_lock(&ddebug_lock); list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) { - if (!strcmp(dt->mod_name, mod_name)) { + if (dt->mod_name == mod_name) { ddebug_table_free(dt); ret = 0; + break; } } mutex_unlock(&ddebug_lock); _
