Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> writes: > On Sat, May 09, 2020 at 12:20:14AM -0700, syzbot wrote: >> memtype_reserve failed: [mem 0xffffffffff000-0x00008fff], req write-back >> WARNING: CPU: 1 PID: 7025 at arch/x86/mm/pat/memtype.c:589 memtype_reserve+0x69f/0x820 arch/x86/mm/pat/memtype.c:589 > > So should memtype_reserve() not do a WARN if given invalid parameters as > it can be triggered by userspace requests? > > A normal "invalid request" debug line is probably all that is needed, > right? I disagree. The callsite espcially if user space triggerable should not attempt to ask for a reservation where start > end: >> memtype_reserve failed: [mem 0xffffffffff000-0x00008fff], req write-back The real question is which part of the call chain is responsible for this. That needs to be fixed. Thanks, tglx