On Wed, 26 Dec 2007, Al Viro wrote: > Erm... Let me spell it out: current lifetime rules are completely broken. > As it is, create/destroy/create cache sequence will do kobject_put() on > kfree'd object. Even without people playing with holding sysfs files > open or doing IO on those.
Urgh. Help! Isnt there some sanity with sysfs? > a) you have kobject embedded into struct with the lifetime rules of its > own. When its refcount hits zero you kfree() the sucker, even if you > still have references to embedded kobject. So alloate it separately? > b) your symlinks stick around. Even when cache is long gone you still > have a sysfs symlink with its embedded kobject as a target. They are > eventually removed when cache with the same name gets created. _Then_ > you get the target kobject dropped - when the memory it used to be in > had been freed for hell knows how long and reused by something that would > not appreciate slub.c code suddenly deciding to decrement some word in > that memory. Hmmmm.. That would also be addressed by a having a separately allocated kobject? > c) you leak references to these kobject; kobject_del() only removes it > from the tree undoing the effect of kobject_add() and you still need > kobject_put() to deal with the last reference. Patches would be appreciated.... Had a hard time to get the sysfs support to work 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/
