From nobody Thu Dec 25 00:26:37 2025 Received: from mail-pf1-f182.google.com (mail-pf1-f182.google.com [209.85.210.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3406D1C68A for ; Fri, 26 Jan 2024 15:29:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706282945; cv=none; b=Go1PmVGkBJOxYzfmydHvfazfxzKXiK7tKDvOcn9pVZxk4CXqXE3cYIQjGnCfT//M+A0Ft/9qdpvN3YH+AJaf7YPHZiM76P2K2uFZ5qnWOSuly3vNcjzKXcZu7G9TRWpPSdJfZQqTQGt8wZeQTh5LRJeDdNJkD2/Fet0HMvKRKuQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706282945; c=relaxed/simple; bh=IDmnKs4KXoXn6lftKlwke8vXRewjXDmMhjWvV+QJ43s=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=iZOyh/ubmQQEHibK/FZjks0XGpjI/6Uo3ZSUhxM0fTLqJjpEOPHDpI8H+TYAEr04UMJDYJNQPMi/OP/+TTMc/0tfDrqI3Lg8DTgL5RksimCUP1/MVkf2Y8/x2X/3ZMMy4QkmoCxpETzFPpaPPwMae9D73pFXY9EECy935vJEuwA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org; spf=pass smtp.mailfrom=chromium.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b=AkwGDV6p; arc=none smtp.client-ip=209.85.210.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=chromium.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="AkwGDV6p" Received: by mail-pf1-f182.google.com with SMTP id d2e1a72fcca58-6d9b37f4804so1288148b3a.1 for ; Fri, 26 Jan 2024 07:29:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1706282943; x=1706887743; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=KDpycj0twAw6yoH+p28gix4mRkksTB474idsqfyTR5s=; b=AkwGDV6pCk1LRoKnWrfbYT0iKc34uG2d66T19JFCa55N9TVRuNf1Ty3lrhPY/jfAm2 ZaWYpzzJ3+AKEYQ2CLVAGoffiTogA4EXH68Yd/+Ut0NTh4TWSiiGKlRL3VyX6/jPzS0C Xsr9ERns2ucePSn1vIDOIUP1nEHRRDd769kSI= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1706282943; x=1706887743; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=KDpycj0twAw6yoH+p28gix4mRkksTB474idsqfyTR5s=; b=TZS6ARlRUR/L/BST+xFLyNDFaXJIcnFiph36PIVda8VT+wSIKsvAdi1IX/ph3bMozZ hX2KJw4R1xguzQCkxt3gdXs9Ela7/Gu3yo5CVgd6LT4dcSwwDao5sGz0yIC61hJdBRMc TezDgfviz4uAGRAkJ3qRdAcEPs84Knbqcgfo2j4x0YmL7bbXPAVJlUvXAEwOjfVfn6bK ywwYGEwQOnt3fJBR0yrKSB2vGOioTbCNE1Mrw9FlCxqJT1rDA5ZLyK1glKrbJSus8gLP e+W06qf9VkE2ol78mLChnBcmUa/2uGQZda+GCF1IkPKGZno2XO+JxmsXogT4cOOOfhD8 bmNQ== X-Gm-Message-State: AOJu0YzdgkIGsFO2XnpXewyDgbBzQY7u+0T8xdmyDEA2NBeqREno6FId 7SA4L814v/sdpOgs0j0pPxheoeFN/zonhjnHakHm8Syn5oUj+BeqjEVLA+oeBg== X-Google-Smtp-Source: AGHT+IG9pu4dsuIMBVO6D7n+zRLG5fIhHfaJd6I9yFebEFRnTlFuxUM1X0By2myfJg9j4+BgP2aNAg== X-Received: by 2002:a05:6a00:c92:b0:6dd:c0a5:3f2e with SMTP id a18-20020a056a000c9200b006ddc0a53f2emr1456979pfv.25.1706282943253; Fri, 26 Jan 2024 07:29:03 -0800 (PST) Received: from dianders.sjc.corp.google.com ([2620:15c:9d:2:8218:45d8:d8fe:f7f2]) by smtp.gmail.com with ESMTPSA id a22-20020a62d416000000b006d9be279432sm1267169pfh.2.2024.01.26.07.29.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 26 Jan 2024 07:29:02 -0800 (PST) From: Douglas Anderson To: Kees Cook Cc: Douglas Anderson , Arnd Bergmann , Greg Kroah-Hartman , linux-kernel@vger.kernel.org Subject: [PATCH] lkdtm/bugs: In lkdtm_HUNG_TASK() use BUG(), not BUG_ON(1) Date: Fri, 26 Jan 2024 07:28:53 -0800 Message-ID: <20240126072852.1.Ib065e528a8620474a72f15baa2feead1f3d89865@changeid> X-Mailer: git-send-email 2.43.0.429.g432eaa2c6b-goog Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" In commit edb6538da3df ("lkdtm/bugs: Adjust lkdtm_HUNG_TASK() to avoid tail call optimization") we marked lkdtm_HUNG_TASK() as __noreturn. The compiler gets unhappy if it thinks a __noreturn function might return, so there's a BUG_ON(1) at the end. Any human can see that the function won't return and the compiler can figure that out too. Except when it can't. The MIPS architecture defines HAVE_ARCH_BUG_ON and defines its own version of BUG_ON(). The MIPS version of BUG_ON() is not a macro but is instead an inline function. Apparently this prevents the compiler from realizing that the condition to BUG_ON() is constant and that the function will never return. Let's change the BUG_ON(1) to just BUG(), which it should have been to begin with. The only reason I used BUG_ON(1) to begin with was because I was used to using WARN_ON(1) when writing test code and WARN() and BUG() are oddly inconsistent in this manner. :-/ Fixes: edb6538da3df ("lkdtm/bugs: Adjust lkdtm_HUNG_TASK() to avoid tail ca= ll optimization") Signed-off-by: Douglas Anderson Reported-by: kernel test robot --- drivers/misc/lkdtm/bugs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c index d1222d3eda2f..b92767d6bdd2 100644 --- a/drivers/misc/lkdtm/bugs.c +++ b/drivers/misc/lkdtm/bugs.c @@ -298,7 +298,7 @@ static void __noreturn lkdtm_HUNG_TASK(void) { set_current_state(TASK_UNINTERRUPTIBLE); schedule(); - BUG_ON(1); + BUG(); } =20 static volatile unsigned int huge =3D INT_MAX - 2; --=20 2.43.0.429.g432eaa2c6b-goog