On 05/11, Linus Torvalds wrote: > > On Sat, 12 May 2007, Oleg Nesterov wrote: > > > > without task_lock() we can see "p->mm != NULL" but not PF_BORROWED_MM. > > Let me explain it one more time: > - shouldn't the *caller* protect this? > > Afaik, there's two situations: > - either things don't change (in which case you don't need locking at > all, since things are statically one way or the other) > - or things change (in which case the caller can't rely on the return > value anyway, since they might change *after* you release the lock)
things change, ->mm is not stable if the kernel thread does use_mm/unuse_mm. However, the return value == 0 does not change in that particular case, exactly because is_user_space() takes task_lock(). Oleg. - 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/
