Andreas Schwab <sch...@linux-m68k.org> writes: > # > # Automatically generated file; DO NOT EDIT. > # Linux/powerpc 5.10.0-rc1 Kernel Configuration > # > CONFIG_CC_VERSION_TEXT="gcc-4.9 (SUSE Linux) 4.9.3"
So it seems to be a combination of GCC 4.9 and ... > # CONFIG_PPC_RADIX_MMU is not set That ^, which specifically causes PPC_KUAP=n. When PPC_KUAP=y allow_user_access() inlines an isync and mtspr, both of which contain a memory clobber, and that seems to hide the bug. I think for now we just have to stop using asm goto for put_user() on GCC 4.9. I'll send a patch for that. cheers
