Hi Rusty, I was going through the splendidly written document, "Unreliable Guide to Locking". I thought of something that should be mentioned in the section "Using Atomic Operations For The Reference Count" (link : http://www.kernel.org/pub/linux/kernel/people/rusty/kernel-locking/x352.html#EXAMPLES-REFCNT-ATOMIC)
I guess, probably the section should also mention that " There is one race condition while using atomic_t, which is as follows : * The refcount of the object is "1". * Process A tries to perform atomic_dec_and_test(), gets "0" and hence performs a kfree() on the object. * Process B tries to perform atomic_inc() on the object. * It may so happen that the atomic_inc() of Process B is called after atomic_dec_and_test(), but before the kfree() call, which is a race condition. Usually, this race condition is avoided as: when the last atomic_dec_and_test() (the last == the one which returns 0) is being called on the object, the object is usually not accessible to others (list_del()) and hence the simultaneous atomic_inc() call never occurs. " Do you think this race condition should be included in the document? Thanks, Kedar. - 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/