From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2199F3019BA; Sat, 5 Sep 2026 08:44:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788597842; cv=none; b=tOwZzR3cQtkWEb8n6VeTklt6cpoOvYZ5nuB6orHquLI7wVc/CwZOWYlUkz33R3Cushj9u+464c+0kJhlbO1XXlMLMvxaBVNpjfqoLW++VFur5MXwp4Sih3QMPNYoGP8K0QETLvVpiyBy3AxZQianAk3MEczrrUrPOq8MDLnn/X0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788597842; c=relaxed/simple; bh=HVNpsjgWPfTAAu+WJ2hwLLqU8d9wbqtfNZgvk7cmuFQ=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=Iy+39JF0vwpbF8Ke6cOUn0ba0XPJIsPf3GwzdfWgSSgT+kbQJ1n8B9BcmtwSZpPS31XOETvPH9AYwiKtotSgW4IZ/EMOwav4AKhegP0JOYrtrEwJARl0CsFlVzLaBtumUdcHUbBQ8W/4QiGOqdGUx6tO3v+aOIX6vfsvsE9Ct9c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=n45UFJeb; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="n45UFJeb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0590B1F00A3D; Sat, 5 Sep 2026 08:43:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788597840; bh=TqHxrurdJhNzBV3eFI/kHdibDuBoPuJBWEjFN7cWhls=; h=From:To:Cc:Subject:In-Reply-To:References:Date; b=n45UFJebFtAjpDIOQvQV6ILE4X7MHItuVnpyCO6mUMJT8AXVeHMpqd0snSOdXyDoC zzU9B/7atWIOLzsPiAei1sXp+RPDcxNsLQp3/HNA7p2/qia6Y7iAOodsD0tPVWfiFn Rd364Le1+++FmU/fQ5K1ezV1jAbMWMnpTPnLAIFuVLH2SAoOWE/202b4OzCkDDk03E vnhgebbCWxSLAMCbCL9agEzksRK33yvkS81CY5FaIqId45H6KHo2fh9gxSEmr1Byz9 sGZd7nGrfZYKmt81BTe9QERcbQmkH/TJ6XI34/347HOhyPu9nWX7pcvFFd+CwQuqUL 6PZlcWRna20YQ== From: Thomas Gleixner To: Philip Li Cc: kernel test robot , oe-kbuild-all@lists.linux.dev, linux-kernel@vger.kernel.org, Jinjie Ruan , linux-riscv@lists.infradead.org Subject: [PATCH] entry: Guard syscall_enter_audit() invocation with CONFIG_AUDITSYSCALL In-Reply-To: <875x0k7i9k.ffs@fw13> References: <202609031938.ZvZZaRQy-lkp@intel.com> <87wlt29k5v.ffs@fw13> <875x0k7i9k.ffs@fw13> Date: Sat, 05 Sep 2026 10:43:57 +0200 Message-ID: <87tso45bqq.ffs@fw13> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain A bunch of older cross compilers notably RISCV64 and S390 fail to eliminate the dead code when CONFIG_AUDITSYSCALL=n. The code in question is: if (unlikely(audit_context()) syscall_enter_audit(regs); and in case of CONFIG_AUDITSYSCALL=n: static inline struct audit_context *audit_context(void) { return NULL; } which should make the compiler eliminate the syscall_enter_audit() call. But a RISV64 GCC12 cross compiler translates that into: if (unlikely(audit_context())) 1c34: 00000097 auipc ra,0x0 1c38: 000080e7 jalr ra # 1c34 <.L785> 1c3c: c511 beqz a0,1c48 <.L787> syscall_enter_audit(regs); 1c3e: 8526 mv a0,s1 1c40: 00000097 auipc ra,0x0 1c44: 000080e7 jalr ra # 1c40 <.L785+0xc> and then claims in the failing link: include/asm-generic/preempt.h:54:(.noinstr.text+0x1a20): undefined reference to 'syscall_enter_audit' which is obviously hallucination. Add an explicit IS_ENABLED(CONFIG_AUDITSYSCALL) check into the condition to cure this compiler madness. Fixes: 6f25517010dd ("entry: Rework syscall_audit_enter()") Reported-by: kernel test robot Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Closes: https://lore.kernel.org/oe-kbuild-all/202609031938.ZvZZaRQy-lkp@intel.com/ --- include/linux/entry-common.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -102,7 +102,14 @@ static __always_inline long syscall_trac if (unlikely(work & SYSCALL_WORK_SYSCALL_TRACEPOINT)) trace_syscall_enter(regs); - if (unlikely(audit_context())) + /* + * The config check works around broken compilers which fail to + * eliminate the dead code in case of CONFIG_AUDITSYSCALL=n as they + * insist on creating a always false runtime condition based on + * audit_context() which returns NULL in that case. The explicit + * IS_ENABLED() check makes that madness go away. + */ + if (IS_ENABLED(CONFIG_AUDITSYSCALL) && unlikely(audit_context())) syscall_enter_audit(regs); return true;