On Wed, 3 Aug 2016 13:53:10 +0800 zhong jiang <zhongjiang@xxxxxxxxxx> wrote: > On 2016/8/2 18:40, Andrey Ryabinin wrote: > > > > On 08/01/2016 10:54 PM, Andrew Morton wrote: > >> On Mon, 1 Aug 2016 23:00:51 +0800 zhongjiang <zhongjiang@xxxxxxxxxx> wrote: > >> > >>> From: zhong jiang <zhongjiang@xxxxxxxxxx> > >>> > >>> At present, It is obvious that memory online and offline will fail > >>> when KASAN enable, > >> huh, I didn't know that. > > Ahem... https://lkml.kernel.org/r/<20150130133552.580f73b97a9bd007979b5419@xxxxxxxxxxxxxxxxxxxx> > > > > Also > > > > commit 786a8959912eb94fc2381c2ae487a96ce55dabca > > kasan: disable memory hotplug > > > > Currently memory hotplug won't work with KASan. As we don't have shadow > > for hotplugged memory, kernel will crash on the first access to it. To > > make this work we will need to allocate shadow for new memory. > > > > At some future point proper memory hotplug support will be implemented. > > Until then, print a warning at startup and disable memory hot-add. > > > > > > > >> What's the problem and are there plans to fix it? > > Nobody complained, so I didn't bother to fix it. > > The fix for this should be simple, I'll look into this. > > > >>> therefore, it is necessary to add the condition > >>> to limit the memory_hotplug when KASAN enable. > >>> > > I don't understand why we need Kconfig dependency. > > Why is that better than runtime warn message? > The user rarely care about the runtime warn message when the > system is good running. In fact, They are confilct with each other. > For me, I know the reason. but I always forget to do so. As a result, > I test the memory hotplug fails again. so, I hope to add the explicit dependency. Yes, I think it's better to disable the configuration than to permit people to run known-to-be-broken kernel setups - that will just cause confusion and pointless bug reports. Let's undo the Kconfig change when this gets fixed up. -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>