On Sun, Feb 18, 2024 at 06:08:14PM +0800, Tong Tiangen wrote: > 1. The copy_mc_to_kernel() is used in the coredump, KSM, and COW > scenarios, in these scenarios, the src mem stores the user data and the > kernel use kernel address to access the src mem(using kmap()). > > 2. the src mem of copy_mc_to_user() is currently only used by the DAX: You mean just because it currently is used somewhere which probably is ok - no clue what DAX does - and even if the source address is still *kernel* memory and even at the danger that someone else might use it in the future and think the handling on a potential #MC is ok, you're still arguing that this is the right thing to do perhaps because it fits your use case?! Sorry Tiangen, not gonna happen. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette