On Mon, Mar 17, 2025 at 10:27:12PM +0100, Ingo Molnar wrote: > > +config OBJTOOL_WERROR > > + bool "Upgrade objtool warnings to errors" > > + depends on OBJTOOL && !COMPILE_TEST > > + help > > + Fail the build on objtool warnings. > > + > > + Objtool warnings can indicate kernel instability, including boot > > + failures. This option is highly recommended. > > + > > + If unsure, say Y. > > My randconfig build tests found this failure of 36 warnings upgraded to > a build failure: > > vmlinux.o: error: objtool: 36 warning(s) upgraded to errors Hm, I'm actually surprised randconfig doesn't set COMPILE_TEST. Anyway, the warnings are valid: vmlinux.o: error: objtool: do_syscall_64+0x40: call to ftrace_likely_update() leaves .noinstr.text section vmlinux.o: error: objtool: do_int80_emulation+0x30: call to ftrace_likely_update() leaves .noinstr.text section vmlinux.o: error: objtool: do_fast_syscall_32+0x7b: call to ftrace_likely_update() leaves .noinstr.text section ... Those are triggered by CONFIG_TRACE_BRANCH_PROFILING which adds a function call to ftrace_likely_update() for every likely() / unlikely(). Which obliterates the noinstr rules. Steven, do you still want to keep that config option? If so, I suppose we could make OBJTOOL_WERROR depend on !TRACE_BRANCH_PROFILING. -- Josh
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