On Thu, Apr 05, 2007 at 05:05:14PM +0200, Cornelia Huck wrote: >On Thu, 5 Apr 2007 22:44:09 +0800, >WANG Cong <[EMAIL PROTECTED]> wrote: > >> On Thu, Apr 05, 2007 at 11:11:42AM +0200, Cornelia Huck wrote: >> >On Thu, 5 Apr 2007 12:54:11 +0800, >> >WANG Cong <[EMAIL PROTECTED]> wrote: >> > >> >> --- linux-2.6.21-rc5-mm3/fs/partitions/check.c.orig 2007-03-30 >> >> 21:35:45.000000000 +0800 >> >> +++ linux-2.6.21-rc5-mm3/fs/partitions/check.c 2007-04-02 >> >> 21:29:02.000000000 +0800 >> >> @@ -385,10 +385,18 @@ void add_partition(struct gendisk *disk, >> >> p->kobj.parent = &disk->kobj; >> >> p->kobj.ktype = &ktype_part; >> >> kobject_init(&p->kobj); >> >> - kobject_add(&p->kobj); >> >> + if (kobject_add(&p->kobj)) { >> >> + kfree(p); >> >> + return; >> >> + } >> >> if (!disk->part_uevent_suppress) >> >> kobject_uevent(&p->kobj, KOBJ_ADD); >> >> - sysfs_create_link(&p->kobj, &block_subsys.kset.kobj, "subsystem"); >> >> + if (sysfs_create_link(&p->kobj, &block_subsys.kset.kobj, "subsystem")) { >> >> + kobject_uevent(&p->kobj, KOBJ_REMOVE); >> >> + kobject_del(&p->kobj); >> >> + kfree(p); >> > >> >You should use kobject_put instead of kfree, since someone could have >> >(theoretically) obtained a reference on the object after the >> >kobject_add. (Or just use kobject_unregister, if the delete uevent >> >isn't suppressed anyway.) >> > >> >> I can't understand that. The memory pointed by 'p' is obtained via >> kmalloc(), _not_ kobject_get. How can we use kobject_put instead? > >The hd_struct *p embeds a kobject kobj (which, amongst other things, >provides reference counting for the hd_struct). The release function >for the kobject will free the embedding object (note that kobject_init >sets the reference count to 1). That means, if kobject_put(&p->kobj) >will drop the reference to 0, the release function (part_release) will >free p. (See also Documentation/kobject.txt.)
Thank you very much! I know. So I should replace all kfree with kobject_put, like this one: - sysfs_create_link(&p->kobj, &block_subsys.kset.kobj, "subsystem"); + if (sysfs_create_link(&p->kobj, &block_subsys.kset.kobj, "subsystem")) { + kobject_uevent(&p->kobj, KOBJ_REMOVE); + kobject_del(&p->kobj); + kobject_put(&p->kobj); + return; + } Is that all right? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/