Re: [PATCH 00/21] objtool: vmlinux.o and CLANG LTO support

From: Nick Desaulniers
Date: Thu Jan 14 2021 - 19:50:19 EST


On Thu, Jan 14, 2021 at 4:41 PM Sami Tolvanen <samitolvanen@xxxxxxxxxx> wrote:
>
> I can confirm that all the warnings I previously saw are now fixed,
> but I'm seeing a few new ones:
>
> vmlinux.o: warning: objtool: balance_leaf_when_delete()+0x17d4: stack
> state mismatch: cfa1=7+192 cfa2=7+176
> vmlinux.o: warning: objtool: internal_move_pointers_items()+0x9f7:
> stack state mismatch: cfa1=7+160 cfa2=7+176
> vmlinux.o: warning: objtool: strncpy_from_user()+0x181: call to
> do_strncpy_from_user() with UACCESS enabled
> vmlinux.o: warning: objtool: strnlen_user()+0x12b: call to
> do_strnlen_user() with UACCESS enabled
> vmlinux.o: warning: objtool: i915_gem_execbuffer2_ioctl()+0x390: call
> to __ubsan_handle_negate_overflow() with UACCESS enabled

^ https://github.com/ClangBuiltLinux/linux/issues/1246, FWIW

> vmlinux.o: warning: objtool: .text.snd_trident_free_voice: unexpected
> end of section
>
> I haven't had a chance to take a closer look yet, but some of these
> are probably related to
> https://github.com/ClangBuiltLinux/linux/issues/1192. However, I can
> reproduce these also with ToT Clang, not just with Clang 11.
>
> Sami



--
Thanks,
~Nick Desaulniers