-
Andy Lutomirski authored
commit 83c133cf upstream. The NMI entry code that switches to the normal kernel stack needs to be very careful not to clobber any extra stack slots on the NMI stack. The code is fine under the assumption that SWAPGS is just a normal instruction, but that assumption isn't really true. Use SWAPGS_UNSAFE_STACK instead. This is part of a fix for some random crashes that Sasha saw. Fixes: 9b6e6a83 ("x86/nmi/64: Switch stacks on userspace NMI entry") Reported-and-tested-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andy Lutomirski <luto@kernel.org> Link: http://lkml.kernel.org/r/974bc40edffdb5c2950a5c4977f821a446b76178.1442791737.git.luto@kernel.orgSigned-off-by: Thomas Gleixner <tglx@linutronix.de> [ luis: backported to 3.16: - file rename: arch/x86/entry/entry_64.S -> arch/x86/kernel/entry_64.S - adjusted context ] Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
528d9753