Re: [PATCH v2 3/8] objtool: stack validation 2.0

From: Ingo Molnar
Date: Fri Jun 30 2017 - 04:32:14 EST



* Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:

> This is a major rewrite of objtool. Instead of only tracking frame
> pointer changes, it now tracks all stack-related operations, including
> all register saves/restores.
>
> In addition to making stack validation more robust, this also paves the
> way for undwarf generation.
>
> Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>

Note, I have applied the first 3 patches, and got a bunch of new warnings on x86
64-bit allmodconfig:

arch/x86/kernel/alternative.o: warning: objtool: do_sync_core()+0x1b: unsupported instruction in callable function
arch/x86/kernel/alternative.o: warning: objtool: text_poke()+0x1a8: unsupported instruction in callable function
arch/x86/kernel/ftrace.o: warning: objtool: do_sync_core()+0x16: unsupported instruction in callable function
arch/x86/kernel/cpu/mcheck/mce.o: warning: objtool: machine_check_poll()+0x166: unsupported instruction in callable function
arch/x86/kernel/cpu/mcheck/mce.o: warning: objtool: do_machine_check()+0x147: unsupported instruction in callable function

(That's the vmlinux build - plus 4 more warnings in the modules build.)

That's with GCC 5.3.1.

Let me know if you need any more info.

Thanks,

Ingo