From: Andy Lutomirski <l...@kernel.org> If something goes wrong with pagetable setup, vsyscall=native will accidentally fall back to emulation. Make it warn and fail so that we notice.
Signed-off-by: Andy Lutomirski <l...@kernel.org> Signed-off-by: Ingo Molnar <mi...@kernel.org> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Cc: Borislav Petkov <b...@alien8.de> Cc: Brian Gerst <brge...@gmail.com> Cc: David Laight <david.lai...@aculab.com> Cc: Kees Cook <keesc...@chromium.org> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> --- arch/x86/entry/vsyscall/vsyscall_64.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/arch/x86/entry/vsyscall/vsyscall_64.c +++ b/arch/x86/entry/vsyscall/vsyscall_64.c @@ -138,6 +138,10 @@ bool emulate_vsyscall(struct pt_regs *re WARN_ON_ONCE(address != regs->ip); + /* This should be unreachable in NATIVE mode. */ + if (WARN_ON(vsyscall_mode == NATIVE)) + return false; + if (vsyscall_mode == NONE) { warn_bad_vsyscall(KERN_INFO, regs, "vsyscall attempted with vsyscall=none");