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SubjectRe: [PATCH 05/37] kdb: core for kgdb back end
Peter Zijlstra wrote:

> On Wed, 2009-12-23 at 15:19 -0600, Jason Wessel wrote:
>
>> diff --git a/kernel/module.c b/kernel/module.c
>> index e96b8ed..25f6a7b 100644
>> --- a/kernel/module.c
>> +++ b/kernel/module.c
>> @@ -79,6 +80,10 @@ EXPORT_TRACEPOINT_SYMBOL(module_get);
>> DEFINE_MUTEX(module_mutex);
>> EXPORT_SYMBOL_GPL(module_mutex);
>> static LIST_HEAD(modules);
>> +#ifdef CONFIG_KGDB_KDB
>> +struct list_head *kdb_modules = &modules; /* kdb needs the list of
>> modules */
>> +#endif /* CONFIG_KGDB_KDB */
>> +
>>

Above we export "modules" so that kdb can emulate lsmod.


The remainder was a port from the original kdb, and should not been
needed. The preempt_disable and preempt_enable should be able to be
safely called while the system in the kgdb exception context, so this
chunk of code is going to get axed and re-tested.

Thanks,
Jason.

>>
>> /* Block module loading/unloading? */
>> int modules_disabled = 0;
>> @@ -2654,8 +2659,14 @@ int module_get_kallsym(unsigned int symnum,
>> unsigned long *value, char *type,
>> char *name, char *module_name, int *exported)
>> {
>> struct module *mod;
>> +#ifdef CONFIG_KGDB_KDB
>> + int get_lock = !KDB_IS_RUNNING();
>> +#else
>> +#define get_lock 1
>> +#endif
>>
>> - preempt_disable();
>> + if (get_lock)
>> + preempt_disable();
>> list_for_each_entry_rcu(mod, &modules, list) {
>> if (symnum < mod->num_symtab) {
>> *value = mod->symtab[symnum].st_value;
>> @@ -2664,12 +2675,14 @@ int module_get_kallsym(unsigned int symnum,
>> unsigned long *value, char *type,
>> KSYM_NAME_LEN);
>> strlcpy(module_name, mod->name,
>> MODULE_NAME_LEN);
>> *exported = is_exported(name, *value, mod);
>> - preempt_enable();
>> + if (get_lock)
>> + preempt_enable();
>> return 0;
>> }
>> symnum -= mod->num_symtab;
>> }
>> - preempt_enable();
>> + if (get_lock)
>> + preempt_enable();
>> return -ERANGE;
>> }
>>



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