> > > > > > So. We are adding the new mapping, we should find all breakpoints this > > > file has in the start/end range. > > > > > > We are holding ->mmap_sem... this seems enough to protect against the > > > races with register/unregister. Except, what if __register_uprobe() > > > fails? In this case __unregister_uprobe() does delete_uprobe() at the > > > very end. What if mmap mmap_uprobe() is called right before delete_? > > > > > > > Because consumers would be NULL before _unregister_uprobe kicks in, we > > shouldnt have a problem here. > > Hmm. But it is not NULL. > > Once again, I didn't mean unregister_uprobe(). I meant register_uprobe(). > In this case, if __register_uprobe() fails, we are doing __unregister > but uprobe->consumer != NULL. Oh Okay, I missed setting uprobe->consumer = NULL once __register_uprobe fails. I shall go ahead and set uprobe->consumer = NULL; (the other option is calling del_consumer() but I dont see a need for calling this.) just before calling __unregister_uprobe() if and only if __register_uprobe fails. > > Just suppose that the caller of register_uprobe() gets a (long) preemption > right before __unregister_uprobe()->delete_uprobe(). What if mmap() is > called at this time? > > > Am I missing something? > > May be you, may be me. Please recheck ;) Rechecked and found the issue. Thanks. > > > I think this would be taken care of if we move the munmap_uprobe() hook > > from unmap_vmas to unlink_file_vma(). > > Probably yes, we should rely on prio_tree locking/changes. > > > The other thing that I need to investigate a bit more is if I have > > handle all cases of mremap correctly. > > Yes. May be mmap_uprobe() should be "closer" to vma_prio_tree_add/insert > too, but I am not sure. Okay, that seems like a good idea. > > Oleg. > -- Thanks and Regards Srikar -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>