Sometimes, device drivers are bound into each other via try_module_get(), making such references invisible when looking at /proc/modules or lsmod.
Add a function to allow setting up module references for such cases, and call it when try_module_get() is used.
Reviewed-by: Dan Williams dan.j.williams@intel.com Reviewed-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Mauro Carvalho Chehab mchehab@kernel.org ---
See [PATCH v4 0/2] at: https://lore.kernel.org/all/cover.1651338466.git.mchehab@kernel.org/
include/linux/module.h | 8 +++++--- kernel/module/main.c | 33 +++++++++++++++++++++++++++++++-- 2 files changed, 36 insertions(+), 5 deletions(-)
diff --git a/include/linux/module.h b/include/linux/module.h index 46d4d5f2516e..3b67720faf3b 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -620,12 +620,12 @@ extern void __module_get(struct module *module);
/* This is the Right Way to get a module: if it fails, it's being removed, * so pretend it's not there. */ -extern bool try_module_get(struct module *module); +extern bool __try_module_get(struct module *module, struct module *this);
extern void module_put(struct module *module);
#else /*!CONFIG_MODULE_UNLOAD*/ -static inline bool try_module_get(struct module *module) +static inline bool __try_module_get(struct module *module, struct module *this) { return !module || module_is_live(module); } @@ -740,7 +740,7 @@ static inline void __module_get(struct module *module) { }
-static inline bool try_module_get(struct module *module) +static inline bool __try_module_get(struct module *module, struct module *this) { return true; } @@ -875,6 +875,8 @@ static inline bool module_sig_ok(struct module *module) } #endif /* CONFIG_MODULE_SIG */
+#define try_module_get(mod) __try_module_get(mod, THIS_MODULE) + int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *, unsigned long), void *data); diff --git a/kernel/module/main.c b/kernel/module/main.c index 05a42d8fcd7a..d63ebf52392b 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -631,6 +631,33 @@ static int ref_module(struct module *a, struct module *b) return 0; }
+static int ref_module_dependency(struct module *mod, struct module *this) +{ + int ret; + + if (!this || !this->name) + return -EINVAL; + + if (mod == this) + return 0; + + mutex_lock(&module_mutex); + + ret = ref_module(this, mod); + +#ifdef CONFIG_MODULE_UNLOAD + if (ret) + goto ret; + + ret = sysfs_create_link(mod->holders_dir, + &this->mkobj.kobj, this->name); +#endif + +ret: + mutex_unlock(&module_mutex); + return ret; +} + /* Clear the unload stuff of the module. */ static void module_unload_free(struct module *mod) { @@ -841,7 +868,7 @@ void __module_get(struct module *module) } EXPORT_SYMBOL(__module_get);
-bool try_module_get(struct module *module) +bool __try_module_get(struct module *module, struct module *this) { bool ret = true;
@@ -856,9 +883,11 @@ bool try_module_get(struct module *module)
preempt_enable(); } + if (ret) + ref_module_dependency(module, this); return ret; } -EXPORT_SYMBOL(try_module_get); +EXPORT_SYMBOL(__try_module_get);
void module_put(struct module *module) {