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Piccoli" , Michael Kelley , kernel test robot Subject: Re: [PATCH 02/11] init: Mark start_kernel() __noreturn Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On Fri, Apr 07, 2023 at 05:09:55PM -0700, Josh Poimboeuf wrote: > Fixes the following warning: > > vmlinux.o: warning: objtool: x86_64_start_reservations+0x28: unreachable instruction > > Reported-by: kernel test robot > Link: https://lore.kernel.org/r/202302161142.K3ziREaj-lkp@intel.com/ > Signed-off-by: Josh Poimboeuf Ah, I just realized that my series will conflict with this. https://lore.kernel.org/llvm/20230412-no_stackp-v1-1-46a69b507a4b@google.com/ Perhaps if my series gets positive feedback; I can rebase it on top of this and it can become part of your series? For this patch, Reviewed-by: Nick Desaulniers Though I'm curious, it does look like it's necessary because of 01/11 in the series? Any idea how the 0day bot report happened before 1/11 existed? (Surely gcc isn't assuming a weak function is implicitly noreturn and make optimizations based on that (that's one hazard I'm worried about)?) It looks like perhaps the link to https://lore.kernel.org/all/202302161142.K3ziREaj-lkp@intel.com/ on 2/11 was 0day testing the arch-cpu-idle-dead-noreturn branch of your kernel tree https://git.kernel.org/pub/scm/linux/kernel/git/jpoimboe/linux.git/log/?h=arch-cpu-idle-dead-noreturn , which had 1/11 in it, IIUC? Perhaps this link should go on 1/11 rather than 2/11? Looking back at 1/11, 3/11, 8/11 I noticed not all patches have links to 0day reports. Are you able to flesh out more info how/what/when such objtool warnings are observed? Are the warnings ever results of patches earlier in the series?