From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=199.89.1.14 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792432611; b=RB/ye8N/xcQ86pqgp7BTlPAU3jyJN4dcDdA5j6q0z6hrzQujyLSLG//rqkr43VHV0wR4 gBHWLeJvDvfXCVC+VAe/pIO5FFZWxsL6IAqYf0+5Kjh1AYYjV23dNOoRop/jBBK90yP5j VMQlOloFVMaJsE/09mIuQee18+DUfgppnbfSdqB3r7vIQpiYr2v60iE6YgLgeln3Kri7I qQP2zOGV+XV9D+NlTP0G5nwtsIjKq5UjAASx6aJF4curKw2XStNus8cblLozxbcTe5Ge1 D1S5rNv0Y2YeM73R/sFYHexFKUxdbfSwnvaR72+jbqhvowsBQpGyROX58qh6n70clRg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792432611; h=DMARC-Filter:Received:DKIM-Signature:X-Virus-Scanned:Received: Received:From:To:Cc:Subject:Date:Message-ID:X-Mailer:In-Reply-To: References:MIME-Version:Content-Transfer-Encoding; bh=DreDO2AJsALB7qq1060EfMBKCRI8UDLOHh4uejtOw6M=; b=IMeCmnINOOwAA+NLnRIyDIXRaogRi3SHPmUm/t2LBOg7Eo3K7vu9qgLtWIAemTLNdMrS RlBdS4B7/RpR/JOINveJi20SnNrS9C6f1XlSVbWtYEQO7F2BHxlw8UWRaSpiwwyQITFc0 0dCRUARM/a615rIH7uRNj7XhL4668780SZs0D98nQyReEu5eBGb9inqxjLvrBbZX3LK1B QTkmeZcTpcRe4+Q2JZzmU9I2gl2SyVMPi1+McDm8VQsFIKfyjJiSl3Cmp4sT8rMUuf/kb MqjMbshzu6+ofFlwDOwJLJlNL7lSobyXjusv8MIP68u8L2KPnrQzpUK16iFMf7Jx7ug== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=acm.org; spf=pass smtp.mailfrom=acm.org; dkim=pass header.d=acm.org header.i=@acm.org header.a=rsa-sha256 header.s=mr01 header.b=himNnIpc; arc=none smtp.remote-ip=199.89.1.14 Received: from 011.lax.mailroute.net (011.lax.mailroute.net [199.89.1.14]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 18B9A606A31B for ; Mon, 19 Oct 2026 17:56:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 18B9A606A31B Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=acm.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=acm.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=acm.org header.i=@acm.org header.a=rsa-sha256 header.s=mr01 header.b=himNnIpc Received: from localhost (localhost [127.0.0.1]) by 011.lax.mailroute.net (Postfix) with ESMTP id 4j7jsn2vsRz1XM6J9; Mon, 19 Oct 2026 17:56:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=acm.org; h= content-transfer-encoding:mime-version:references:in-reply-to :x-mailer:message-id:date:date:subject:subject:from:from :received:received; s=mr01; t=1792432603; x=1795024604; bh=DreDO 2AJsALB7qq1060EfMBKCRI8UDLOHh4uejtOw6M=; b=himNnIpcBsOlty+xzeA6k 5Qjp/OiPBPmk1yfwffoLXWYkh3KxHuPqPGg79xt3aVZwxb9HsPR80jCMKTBC2uuG jARryjBxfWysGVVSYg45TVZkMkiVpYXnzkF6Nv03jXITT1Ho4JzOY48bQbpJl712 LnWl/gyc+uQl0P+S/zIi71x7MyzulyGzan7zXBshu72fMh8iW5h75eGxuTy7M1XY QU1wouXD/eWzs/dG1BWlB48x0QPZ5qGXKfaN6tl3Vhdu32LlnqCX7xnDciWPUvfq 0CM/IHkuaK5JpEX1JjLTknyzeNlGspwgkarMYXhi+F+wNithQ2dIhszRgyFp5rsg w== X-Virus-Scanned: by MailRoute Received: from 011.lax.mailroute.net ([127.0.0.1]) by localhost (011.lax [127.0.0.1]) (mroute_mailscanner, port 10029) with LMTP id mrZGFsalEs67; Mon, 19 Oct 2026 17:56:43 +0000 (UTC) Received: from bvanassche.c.googlers.com.com (245.199.118.34.bc.googleusercontent.com [34.118.199.245]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bvanassche@acm.org) by 011.lax.mailroute.net (Postfix) with ESMTPSA id 4j7jsk3wZWz1XM30h; Mon, 19 Oct 2026 17:56:42 +0000 (UTC) From: Bart Van Assche To: linux-sparse@vger.kernel.org Cc: Bart Van Assche Subject: [PATCH 03/20] bits: Guard against out-of-bounds bit shifts in bitmask helpers Date: Mon, 19 Oct 2026 10:56:16 -0700 Message-ID: <20261019175633.415493-4-bvanassche@acm.org> X-Mailer: git-send-email 2.56.0.212.g129ede20d9-goog In-Reply-To: <20261019175633.415493-1-bvanassche@acm.org> References: <20261019175633.415493-1-bvanassche@acm.org> X-Mailing-List: linux-sparse@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Clamp bit widths to [0, 64] in bits.h and fix 64-bit shift calculations in bitmap.h to avoid undefined shift behavior on 64-bit integers. Signed-off-by: Bart Van Assche --- bitmap.h | 2 +- bits.h | 12 ++++++++---- 2 files changed, 9 insertions(+), 5 deletions(-) diff --git a/bitmap.h b/bitmap.h index 4d81ffc07538..1f5d2ce48b24 100644 --- a/bitmap.h +++ b/bitmap.h @@ -2,7 +2,7 @@ #define BITMAP_H =20 #define BITS_IN_LONG (sizeof(unsigned long)*8) -#define LONGS(x) ((x + BITS_IN_LONG - 1) & -BITS_IN_LONG) +#define LONGS(x) (((x) + BITS_IN_LONG - 1) / BITS_IN_LONG) =20 /* Every bitmap gets its own type */ #define DECLARE_BITMAP(name, x) unsigned long name[LONGS(x)] diff --git a/bits.h b/bits.h index 9908190d8c2f..23ee8805479c 100644 --- a/bits.h +++ b/bits.h @@ -12,19 +12,23 @@ =20 static inline unsigned long long sign_bit(unsigned size) { + if (!size) + return 0; + if (size > 64) + size =3D 64; return 1ULL << (size - 1); } =20 static inline unsigned long long sign_mask(unsigned size) { unsigned long long sbit =3D sign_bit(size); - return sbit - 1; + return sbit ? sbit - 1 : 0; } =20 static inline unsigned long long bits_mask(unsigned size) { unsigned long long sbit =3D sign_bit(size); - return sbit | (sbit - 1); + return sbit | (sbit ? sbit - 1 : 0); } =20 =20 @@ -58,7 +62,7 @@ static inline long long bits_extend(long long val, unsi= gned size, int is_signed) return val; } =20 -static inline int is_power_of_2(long long val) +static inline int is_power_of_2(unsigned long long val) { return val && !(val & (val - 1)); } @@ -67,7 +71,7 @@ static inline int is_power_of_2(long long val) // log base 2 of an exact power-of-2 static inline int log2_exact(unsigned long long val) { - return 8 * sizeof(val) - __builtin_clzl(val) - 1; + return 8 * sizeof(val) - __builtin_clzll(val) - 1; } =20 #endif