Commit 52796312 authored by Zhou Chengming's avatar Zhou Chengming Committed by Jessica Yu
Browse files

module: fix ddebug_remove_module() 



ddebug_remove_module() use mod->name to find the ddebug_table of the
module and remove it. But dynamic_debug_setup() use the first
_ddebug->modname to create ddebug_table for the module. It's ok when
the _ddebug->modname is the same with the mod->name.

But livepatch module is special, it may contain _ddebugs of other
modules, the modname of which is different from the name of livepatch
module. So ddebug_remove_module() can't use mod->name to find the
right ddebug_table and remove it. It can cause kernel crash when we cat
the file <debugfs>/dynamic_debug/control.

Signed-off-by: default avatarZhou Chengming <zhouchengming1@huawei.com>
Signed-off-by: default avatarJessica Yu <jeyu@kernel.org>
parent 4fd3e4ef

kernel/module.c

+6 −6
Original line number Diff line number Diff line
@@ -2707,21 +2707,21 @@ static void add_kallsyms(struct module *mod, const struct load_info *info) 
}

#endif /* CONFIG_KALLSYMS */



static void dynamic_debug_setup(struct _ddebug *debug, unsigned int num)

static void dynamic_debug_setup(struct module *mod, struct _ddebug *debug, unsigned int num)

{

	if (!debug)

		return;

#ifdef CONFIG_DYNAMIC_DEBUG

	if (ddebug_add_module(debug, num, debug->modname))

	if (ddebug_add_module(debug, num, mod->name))

		pr_err("dynamic debug error adding module: %s\n",

			debug->modname);

#endif

}



static void dynamic_debug_remove(struct _ddebug *debug)

static void dynamic_debug_remove(struct module *mod, struct _ddebug *debug)

{

	if (debug)

		ddebug_remove_module(debug->modname);

		ddebug_remove_module(mod->name);

}



void * __weak module_alloc(unsigned long size)
@@ -3715,7 +3715,7 @@ static int load_module(struct load_info *info, const char __user *uargs, 
		goto free_arch_cleanup;

	}



	dynamic_debug_setup(info->debug, info->num_debug);

	dynamic_debug_setup(mod, info->debug, info->num_debug);



	/* Ftrace init must be called in the MODULE_STATE_UNFORMED state */

	ftrace_module_init(mod);
@@ -3779,7 +3779,7 @@ static int load_module(struct load_info *info, const char __user *uargs, 
	module_disable_nx(mod);



 ddebug_cleanup:

	dynamic_debug_remove(info->debug);

	dynamic_debug_remove(mod, info->debug);

	synchronize_sched();

	kfree(mod->args);

 free_arch_cleanup:

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