On Fri, Feb 02, 2024 at 03:51:12PM +0800, Tong Tiangen wrote: > Currently, there are some kernel memory copy scenarios is also mc safe > which use copy_mc_to_kernel() or copy_mc_user_highpage(), these kernel- > to-kernel copy use fixup_type EX_TYPE_DEFAULT_MCE_SAFE. In these > scenarios, posion pages need to be isolated too and the current So you have, for example: unsigned long __must_check copy_mc_to_kernel(void *dst, const void *src, unsigned len) Now imagine you get a MCE for *dst which is some kernel page which cannot be poisoned: direct map, kernel text, and so on. Attempting to poison such a page would not work, to put it mildly. So, again, what *exactly* are you "fixing" here? When I read "Currently, there are some kernel memory copy scenarios" and there's nothing more explaining what those scenarios are, I'm tempted to ignore this completely until you give a detailed and concrete example what the problem is: What exactly are you doing, what goes wrong, why does this need to be fixed and so on... If there isn't such a real-life use case you're encountering, then this all is waste of time. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette