From patchwork Tue Apr 12 06:29:54 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 560510 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 969F4C3527B for ; Tue, 12 Apr 2022 07:29:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231795AbiDLHah (ORCPT ); Tue, 12 Apr 2022 03:30:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60302 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353059AbiDLHZM (ORCPT ); Tue, 12 Apr 2022 03:25:12 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CADC84D638; Tue, 12 Apr 2022 00:00:07 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6B4E3615B4; Tue, 12 Apr 2022 07:00:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77A3EC385AA; Tue, 12 Apr 2022 07:00:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649746806; bh=qT4rRxjdgHvgFLUUTFXORG38wBgzvPAGzYgrVrQ2Wyk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jcveiLWjT1mWudMNksZFPKHY90jUtRRcyHc1bz8L1WaZNDzPkK3XkM8UmGxBwzrVr EGzsrpxSgeP1gnd4+Q8h6cHveaDFZJLLywJGR+aMSs+FQ/smOiHt6BEB5BjjqhXiQh r5TrfxEXBg1WNqbL3srf/GG9Igov5Wt1p8vl/hcY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Peter Zijlstra (Intel)" , Josh Poimboeuf , Sasha Levin Subject: [PATCH 5.16 137/285] x86: Annotate call_on_stack() Date: Tue, 12 Apr 2022 08:29:54 +0200 Message-Id: <20220412062947.621591678@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220412062943.670770901@linuxfoundation.org> References: <20220412062943.670770901@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Peter Zijlstra [ Upstream commit be0075951fde739f14ee2b659e2fd6e2499c46c0 ] vmlinux.o: warning: objtool: page_fault_oops()+0x13c: unreachable instruction 0000 000000000005b460 : ... 0128 5b588: 49 89 23 mov %rsp,(%r11) 012b 5b58b: 4c 89 dc mov %r11,%rsp 012e 5b58e: 4c 89 f2 mov %r14,%rdx 0131 5b591: 48 89 ee mov %rbp,%rsi 0134 5b594: 4c 89 e7 mov %r12,%rdi 0137 5b597: e8 00 00 00 00 call 5b59c 5b598: R_X86_64_PLT32 handle_stack_overflow-0x4 013c 5b59c: 5c pop %rsp vmlinux.o: warning: objtool: sysvec_reboot()+0x6d: unreachable instruction 0000 00000000000033f0 : ... 005d 344d: 4c 89 dc mov %r11,%rsp 0060 3450: e8 00 00 00 00 call 3455 3451: R_X86_64_PLT32 irq_enter_rcu-0x4 0065 3455: 48 89 ef mov %rbp,%rdi 0068 3458: e8 00 00 00 00 call 345d 3459: R_X86_64_PC32 .text+0x47d0c 006d 345d: e8 00 00 00 00 call 3462 345e: R_X86_64_PLT32 irq_exit_rcu-0x4 0072 3462: 5c pop %rsp Both cases are due to a call_on_stack() calling a __noreturn function. Since that's an inline asm, GCC can't do anything about the instructions after the CALL. Therefore put in an explicit ASM_REACHABLE annotation to make sure objtool and gcc are consistently confused about control flow. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Josh Poimboeuf Link: https://lore.kernel.org/r/20220308154319.468805622@infradead.org Signed-off-by: Sasha Levin --- arch/x86/include/asm/irq_stack.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/irq_stack.h b/arch/x86/include/asm/irq_stack.h index ae9d40f6c706..05af249d6bec 100644 --- a/arch/x86/include/asm/irq_stack.h +++ b/arch/x86/include/asm/irq_stack.h @@ -99,7 +99,8 @@ } #define ASM_CALL_ARG0 \ - "call %P[__func] \n" + "call %P[__func] \n" \ + ASM_REACHABLE #define ASM_CALL_ARG1 \ "movq %[arg1], %%rdi \n" \