> On Jan 4, 2018, at 12:29 PM, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > >> On Thu, Jan 4, 2018 at 12:16 PM, Thomas Voegtle <tv@xxxxxxxx> wrote: >> >> Attached a screenshot. >> Is that useful? Are there some debug options I can add? > > Not much of an oops, because the SIGSEGV happens in user space. The > only reason you get any kernel stack printout at all is because 'init' > dying will make the kernel print that out. > > The segfault address for init looks like the fixmap area to me (first > byte in the last page of the fixmap?). "Error 5" means that it's a > user-space read that got a protection fault. So it's not a LDT of GDT > update or anything like that, it's a normal access from user space (or > a qemu emulation bug, but that sounds unlikely). > > Is that the vsyscall page? > > Adding Luto to the participants. I think he noticed one of the > vsyscall patches missing earlier in the 4.9 series. Maybe the 4.4 > series had something similar.. > That's almost certainly it. I'll try to find some time today or tomorrow to add a proper selftest. > Linus