+++ Zhiqiang Liu [28/06/19 20:32 +0800]:
From: Zhiqiang Liu <[email protected]>Problem: Users can call ref_module func in their modules to construct relationships with other modules. However, the holders '/sys/module/<mod-name>/holders' of the target module donot include the users` module. So lsmod command misses detailed info of 'Used by'. When load module, the process is given as follows, load_module() -> mod_sysfs_setup() -> add_usage_links -> do_init_module -> mod->init() add_usage_links func creates holders of target modules linking to this module. If ref_module is called in mod->init() func, the usage links cannot be added. Here, we will add usage link of a to b's holder_dir. Fixes: 9bea7f239 ("module: fix bne2 "gave up waiting for init of module libcrc32c")
I think we can drop this tag; it doesn't fix a bug specifically introduced by that particular commit.
Signed-off-by: Zhiqiang Liu <[email protected]> --- kernel/module.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/module.c b/kernel/module.c index 80c7c09584cf..11c6aff37b1f 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -871,6 +871,11 @@ int ref_module(struct module *a, struct module *b) module_put(b); return err; } + + err = sysfs_create_link(b->holders_dir, &a->mkobj.kobj, a->name); + if (err) + return err;
We need to fix the error handling here - the module_use struct allocated in the call to add_module_usage() needs to be freed (you could just modify add_module_usage() to return the use pointer so that it's easier to free from within ref_module()), module_put() needs to be called, and the use struct should be removed from its respective lists (see module_unload_free()). Thanks, Jessica
