From 231b895daa0224864858df3e936fdbcdef8f9912 Mon Sep 17 00:00:00 2001 From: Petr Pavlu Date: Fri, 13 Mar 2026 14:48:02 +0100 Subject: [PATCH] module: Fix freeing of charp module parameters when CONFIG_SYSFS=n [ Upstream commit deffe1edba626d474fef38007c03646ca5876a0e ] When setting a charp module parameter, the param_set_charp() function allocates memory to store a copy of the input value. Later, when the module is potentially unloaded, the destroy_params() function is called to free this allocated memory. However, destroy_params() is available only when CONFIG_SYSFS=y, otherwise only a dummy variant is present. In the unlikely case that the kernel is configured with CONFIG_MODULES=y and CONFIG_SYSFS=n, this results in a memory leak of charp values when a module is unloaded. Fix this issue by making destroy_params() always available when CONFIG_MODULES=y. Rename the function to module_destroy_params() to clarify that it is intended for use by the module loader. Fixes: e180a6b7759a ("param: fix charp parameters set via sysfs") Signed-off-by: Petr Pavlu Signed-off-by: Sami Tolvanen Signed-off-by: Sasha Levin --- include/linux/moduleparam.h | 11 +++-------- kernel/module/main.c | 4 ++-- kernel/params.c | 27 ++++++++++++++++++--------- 3 files changed, 23 insertions(+), 19 deletions(-) diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h index 061e19c94a6b..f73ca4d62683 100644 --- a/include/linux/moduleparam.h +++ b/include/linux/moduleparam.h @@ -392,14 +392,9 @@ extern char *parse_args(const char *name, const char *doing, void *arg)); /* Called by module remove. */ -#ifdef CONFIG_SYSFS -extern void destroy_params(const struct kernel_param *params, unsigned num); -#else -static inline void destroy_params(const struct kernel_param *params, - unsigned num) -{ -} -#endif /* !CONFIG_SYSFS */ +#ifdef CONFIG_MODULES +void module_destroy_params(const struct kernel_param *params, unsigned int num); +#endif /* All the helper functions */ /* The macros to do compile-time type checking stolen from Jakub diff --git a/kernel/module/main.c b/kernel/module/main.c index 76d90c20de67..ac528fbb6282 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -1261,7 +1261,7 @@ static void free_module(struct module *mod) module_unload_free(mod); /* Free any allocated parameters. */ - destroy_params(mod->kp, mod->num_kp); + module_destroy_params(mod->kp, mod->num_kp); if (is_livepatch_module(mod)) free_module_elf(mod); @@ -2998,7 +2998,7 @@ static int load_module(struct load_info *info, const char __user *uargs, mod_sysfs_teardown(mod); coming_cleanup: mod->state = MODULE_STATE_GOING; - destroy_params(mod->kp, mod->num_kp); + module_destroy_params(mod->kp, mod->num_kp); blocking_notifier_call_chain(&module_notify_list, MODULE_STATE_GOING, mod); klp_module_going(mod); diff --git a/kernel/params.c b/kernel/params.c index 2cfa12404ed0..9d09ea99363f 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -744,15 +744,6 @@ void module_param_sysfs_remove(struct module *mod) } #endif -void destroy_params(const struct kernel_param *params, unsigned num) -{ - unsigned int i; - - for (i = 0; i < num; i++) - if (params[i].ops->free) - params[i].ops->free(params[i].arg); -} - struct module_kobject * __init_or_module lookup_or_create_module_kobject(const char *name) { @@ -987,3 +978,21 @@ static int __init param_sysfs_builtin_init(void) late_initcall(param_sysfs_builtin_init); #endif /* CONFIG_SYSFS */ + +#ifdef CONFIG_MODULES + +/* + * module_destroy_params - free all parameters for one module + * @params: module parameters (array) + * @num: number of module parameters + */ +void module_destroy_params(const struct kernel_param *params, unsigned int num) +{ + unsigned int i; + + for (i = 0; i < num; i++) + if (params[i].ops->free) + params[i].ops->free(params[i].arg); +} + +#endif /* CONFIG_MODULES */