> > > > > > I agree, sometimes it makes sense to protect against the stupid mistakes, > > > but if we want to check against NULL we should do > > > > > > if (WARN_ON(!inode)) > > > return; > > > > > > > agree, that warn_on is better than a simple check > > and this one > > if (WARN_ON(inode < PAGE_OFFSET)) > > is even better ;)
Okay. > > > > Especially in uprobe_unregister(). The current code is really "hide > > > the possible problem" and nothing more. It is better to crash imho > > > than silently return. > > > > > > > > register() also checks uc->next == NULL, probably to prevent the > > > > > double-register but the caller can do other stupid/wrong things. > > > > > > > > Users can surely do more stupid things. But this is again something that > > > > kernel can identify. By allowing a double-register of a consumer, thats > > > > already registered, we might end up allowing circular loop of consumers. > > > > > > I understand. But in this case we should document that uc->next must > > > be cleared before uprobe_register(). Or add init_consumer(). > > > > > > And we should change uprobe_unregister() to clear uc->next as well. > > > I think that the code like this > > > > > > uprobe_register(uc); > > > uprobe_unregister(uc); > > > > > > uprobe_register(uc); > > > > > > should work. Currently it doesn't because of this check. > > > > > > > yes, these should work and makes a case to nullify ->next on unregister. > > > > However, what if someone tries > > > > uprobe_register(uc1); > > uprobe_register(uc2); > > uprobe_register(uc1); > > > > i.e somebody tries to re-register uc1, while its active and has a valid > > next. After the re-registration of uc1, the uprobe->consumers will no more > > reference uc2. > > Yes. And even without uprobe_register(uc2) the result won't be good. > This is like list_add(node). > > > Should we leave this case as a fool shooting himself? > > IMHO yes, or we should create init_consumer() or at least document that > the private ->next member should be nullified. > Okay, Since we agree that its a user mistake. So lets document this and continue with what you propose. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
