Commit cdf6d006 authored Mar 07, 2019 by Rasmus Villemoes Committed by Linus Torvalds Mar 07, 2019

dynamic_debug: don't duplicate modname in ddebug_add_module

For built-in modules, we're already reusing the passed-in string via
kstrdup_const().  But for actual modules (i.e.  when we're called from
dynamic_debug_setup in module.c), the passed-in string (which points at
the name[] array inside struct module) is also guaranteed to live at
least as long as the struct ddebug_table, since free_module() calls
ddebug_remove_module().

Link: http://lkml.kernel.org/r/20190212214150.4807-6-linux@rasmusvillemoes.dk


Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Jason Baron <jbaron@akamai.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 2bdde670

lib/dynamic_debug.c

+7 −8

Original line number	Diff line number	Diff line
		@@ -847,17 +847,17 @@ int ddebug_add_module(struct _ddebug *tab, unsigned int n,
		const char *name)
		{
		struct ddebug_table *dt;
		const char *new_name;

		dt = kzalloc(sizeof(*dt), GFP_KERNEL);
		if (dt == NULL)
		return -ENOMEM;
		new_name = kstrdup_const(name, GFP_KERNEL);
		if (new_name == NULL) {
		kfree(dt);
		return -ENOMEM;
		}
		dt->mod_name = new_name;
		/*
		* For built-in modules, name lives in .rodata and is
		* immortal. For loaded modules, name points at the name[]
		* member of struct module, which lives at least as long as
		* this struct ddebug_table.
		*/
		dt->mod_name = name;
		dt->num_ddebugs = n;
		dt->ddebugs = tab;

		@@ -913,7 +913,6 @@ int ddebug_dyndbg_module_param_cb(char param, char val, const char *module)
		static void ddebug_table_free(struct ddebug_table *dt)
		{
		list_del_init(&dt->link);
		kfree_const(dt->mod_name);
		kfree(dt);
		}

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