On Wed, Aug 16, 2017 at 09:08:08PM +0200, Alexander Potapenko wrote: > __startup_64() is normally using fixup_pointer() to access globals in a > position-independent fashion. However |next_early_pgt| was accessed > directly, which wasn't guaranteed to work. > > Luckily GCC was generating a R_X86_64_PC32 PC-relative relocation for > |next_early_pgt|, but Clang emitted a R_X86_64_32S, which led to > accessing invalid memory and rebooting the kernel.
Thanks for tracking this down. Acked-by: Kirill A. Shutemov <[email protected]> > Cc: Kirill A. Shutemov <[email protected]> > Cc: Dmitry Vyukov <[email protected]> > Cc: Michael Davidson <[email protected]> > Fixes: c88d71508e36 ("x86/boot/64: Rewrite startup_64() in C") Cc: <[email protected]> # 4.12 -- Kirill A. Shutemov
