On 11/29/15 00:05, Ingo Molnar wrote: > > * Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote: > >>>> - print a warning and a backtrace, and just mark the page read-write >>>> so that the machine survives, but we get notified and can fix whatever >>>> broken code >>> >>> This seems very easy to add. Should I basically reverse the effects of >>> mark_rodata_ro(), or should I only make the new ro-after-init section as RW? >>> (I think the former would be easier.) >> >> I'd suggest verifying that the page in question is .data..ro_after_init and, if >> so, marking that one page RW. > > Yes, this was PaX's suggestion as well, and I agree: doing that turns a quite > possibly unrecoverable boot/shutdown time or suspend/resume time (suspend is > really a special category of 'bootup') crasher oops into a more informative stack > dump. > > These ro related faults tend to trigger when init/deinit is running, and oopsing > in those sequences is typically a lot less survivable than say oopsing in a high > level system call while not holding locks. > I think what should do is have a debug option which can be set to "rw", "log" or "oops"; the latter should probably be the default. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
