Quoting r. Hugh Dickins <[EMAIL PROTECTED]>: > > > The other reason I dislike the patch is that the problem it fixes is > > > an old one, and I'd much rather have get_user_pages fix it for itself, > > > > Please note that the problem this attempts to solve is not limited > > to pages locked by get_user_pages: in an infiniband userspace initiator, > > a hardware page is mapped into process memory and must not be inherited > > by a child processes, otherwise hardware protection breaks. > > Interesting. > > But (correct me if I'm wrong, I know nothing about InfiniBand userspace > initiators) that would be done by a driver, which can set VM_DONTCOPY > on the vma, without us having to extend the mprotect or madvise API
Roland, Hugh here proposes setting VM_DONTCOPY on user-mapped PIO memory from driver on mmap, to protect against child process corrupting parent's user access region. IIRC, we used to set this bit, but it was removed later - could you please clarify why? Do you think its a good idea to restore this behaviour? -- MST - 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/
