params: cleanup sysfs allocation
commit 63662139e5
attempted to patch a
leak (which would only happen on OOM, ie. never), but it didn't quite
work.
This rewrites the code to be as simple as possible. add_sysfs_param()
adds a parameter. If it fails, it's the caller's responsibility to
clean up the parameters which already exist.
The kzalloc-then-always-krealloc pattern is perhaps overly simplistic,
but this code has clearly confused people. It worked on me...
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
parent
6da0b56515
commit
18eb74fa94
@ -603,73 +603,64 @@ static __modinit int add_sysfs_param(struct module_kobject *mk,
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const struct kernel_param *kp,
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const char *name)
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{
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struct module_param_attrs *new;
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struct attribute **attrs;
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int err, num;
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struct module_param_attrs *new_mp;
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struct attribute **new_attrs;
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unsigned int i;
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/* We don't bother calling this with invisible parameters. */
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BUG_ON(!kp->perm);
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if (!mk->mp) {
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num = 0;
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attrs = NULL;
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} else {
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num = mk->mp->num;
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attrs = mk->mp->grp.attrs;
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}
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/* Enlarge. */
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new = krealloc(mk->mp,
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sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (num+1),
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/* First allocation. */
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mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL);
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if (!mk->mp)
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return -ENOMEM;
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mk->mp->grp.name = "parameters";
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/* NULL-terminated attribute array. */
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mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]),
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GFP_KERNEL);
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if (!new) {
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kfree(attrs);
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err = -ENOMEM;
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goto fail;
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}
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/* Despite looking like the typical realloc() bug, this is safe.
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* We *want* the old 'attrs' to be freed either way, and we'll store
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* the new one in the success case. */
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attrs = krealloc(attrs, sizeof(new->grp.attrs[0])*(num+2), GFP_KERNEL);
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if (!attrs) {
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err = -ENOMEM;
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goto fail_free_new;
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/* Caller will cleanup via free_module_param_attrs */
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if (!mk->mp->grp.attrs)
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return -ENOMEM;
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}
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/* Sysfs wants everything zeroed. */
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memset(new, 0, sizeof(*new));
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memset(&new->attrs[num], 0, sizeof(new->attrs[num]));
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memset(&attrs[num], 0, sizeof(attrs[num]));
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new->grp.name = "parameters";
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new->grp.attrs = attrs;
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/* Enlarge allocations. */
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new_mp = krealloc(mk->mp,
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sizeof(*mk->mp) +
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sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1),
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GFP_KERNEL);
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if (!new_mp)
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return -ENOMEM;
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mk->mp = new_mp;
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/* Extra pointer for NULL terminator */
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new_attrs = krealloc(mk->mp->grp.attrs,
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sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2),
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GFP_KERNEL);
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if (!new_attrs)
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return -ENOMEM;
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mk->mp->grp.attrs = new_attrs;
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/* Tack new one on the end. */
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sysfs_attr_init(&new->attrs[num].mattr.attr);
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new->attrs[num].param = kp;
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new->attrs[num].mattr.show = param_attr_show;
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new->attrs[num].mattr.store = param_attr_store;
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new->attrs[num].mattr.attr.name = (char *)name;
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new->attrs[num].mattr.attr.mode = kp->perm;
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new->num = num+1;
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sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr);
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mk->mp->attrs[mk->mp->num].param = kp;
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mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show;
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mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store;
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mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name;
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mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm;
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mk->mp->num++;
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/* Fix up all the pointers, since krealloc can move us */
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for (num = 0; num < new->num; num++)
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new->grp.attrs[num] = &new->attrs[num].mattr.attr;
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new->grp.attrs[num] = NULL;
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mk->mp = new;
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for (i = 0; i < mk->mp->num; i++)
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mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr;
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mk->mp->grp.attrs[mk->mp->num] = NULL;
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return 0;
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fail_free_new:
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kfree(new);
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fail:
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mk->mp = NULL;
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return err;
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}
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#ifdef CONFIG_MODULES
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static void free_module_param_attrs(struct module_kobject *mk)
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{
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if (mk->mp)
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kfree(mk->mp->grp.attrs);
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kfree(mk->mp);
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mk->mp = NULL;
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@ -695,8 +686,10 @@ int module_param_sysfs_setup(struct module *mod,
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if (kparam[i].perm == 0)
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continue;
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err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
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if (err)
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if (err) {
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free_module_param_attrs(&mod->mkobj);
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return err;
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}
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params = true;
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}
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