On Tue, Apr 28, 2020 at 04:49:15PM +0200, Arnd Bergmann wrote: > I noticed the number of objtool warnings in randconfig kernels have gone down > recently, maybe it's possible to eliminate the remaining ones? > > Here are the ones I ran into recently, using gcc-9.3: > > ==> build/x86/0x3D2B5D6D_defconfig/log <== > arch/x86/kvm/vmx/vmx.o: warning: objtool: vmx_handle_exit_irqoff()+0x24: > unreachable instruction
This is a legit warning caused by CONFIG_UBSAN_TRAP + CONFIG_UBSAN_ALIGNMENT, I think Kees is going to do a fix. > ==> build/x86/0xFD7B7323_defconfig/log <== > arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x991: unreachable > instruction This warning looks correct, did you make a change to entry_64.S? > ==> build/x86/0x7942F24A_defconfig/log <== > samples/ftrace/ftrace-direct.o: warning: objtool: .text+0x0: unreachable > instruction > samples/ftrace/ftrace-direct-too.o: warning: objtool: .text+0x0: unreachable > instruction > samples/ftrace/ftrace-direct-modify.o: warning: objtool: .text+0x0: > unreachable instruction I posted a fix for these a few days ago: https://lkml.kernel.org/r/86c1cbca67cb353da9f335643ef5fd19bd82988f.1587761369.git.jpoim...@redhat.com > ==> build/x86/0xE0F2ACFF_defconfig/log <== > kernel/time/posix-stubs.o: warning: objtool: __x64_sys_timer_create()+0x23: > sibling call from callable instruction with modified stack frame > > ==> build/x86/0x2EA4CE4F_defconfig/log <== > kernel/kcov.o: warning: objtool: write_comp_data()+0x1b: call to > check_kcov_mode() with UACCESS enabled > kernel/kcov.o: warning: objtool: __sanitizer_cov_trace_pc()+0x15: call to > check_kcov_mode() with UACCESS enabled > > ==> build/x86/0x500B1B82_defconfig/log <== > kernel/bpf/core.o: warning: objtool: ___bpf_prog_run()+0x1269: call > without frame pointer save/setup I'll look into these. -- Josh
