On Wed, Aug 28, 2019 at 11:00 AM Arnd Bergmann <a...@arndb.de> wrote: > On Tue, Aug 27, 2019 at 11:22 PM 'Nick Desaulniers' via Clang Built Linux > <clang-built-li...@googlegroups.com> wrote: I figured this one out as well:
> http://paste.ubuntu.com/p/XjdDsypRxX/ > 0x5BA1B7A1:arch/x86/ia32/ia32_signal.o: warning: objtool: > ia32_setup_rt_frame()+0x238: call to memset() with UACCESS enabled > 0x5BA1B7A1:arch/x86/kernel/signal.o: warning: objtool: > __setup_rt_frame()+0x5b8: call to memset() with UACCESS enabled When CONFIG_KASAN is set, clang decides to use memset() to set the first two struct members in this function: static inline void sas_ss_reset(struct task_struct *p) { p->sas_ss_sp = 0; p->sas_ss_size = 0; p->sas_ss_flags = SS_DISABLE; } and that is called from save_altstack_ex(). Adding a barrier() after the sas_ss_sp() works around the issue, but is certainly not the best solution. Any other ideas? Arnd
